Optimizer Hints | PingCAP 文档中心

link之家

链接快照平台

输入网页链接，自动生成快照
标签化管理网页链接

相关文章推荐

乐观的芒果 · Sql实现某列的值转为列名-CSDN博客· 1 年前 ·

乐观的红豆 · sql int转date-掘金· 2 年前 ·

苦闷的鞭炮 · 使用Retrofit与Rails API· 2 年前 ·

风流的日记本 · [VSCode] Visual ...· 2 年前 ·

</noscript><noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-TPX49SBK" height="0" width="0" style="display: none; visibility: hidden" aria-hidden="true"/></noscript><div id="___gatsby"><div style="outline:none" tabindex="-1" id="gatsby-focus-wrapper"><style data-emotion="css 1agcunv">.css-1agcunv{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;width:100%;box-sizing:border-box;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;position:fixed;z-index:1100;top:0;left:auto;right:0;background-color:#1976d2;color:#fff;background-color:#f9f9f9;border-bottom:1px solid #e5e5e5;box-shadow:0px 1px 6px rgba(0, 0, 0, 0.08);height:7rem;}@media print{.css-1agcunv{}}</style><style data-emotion="css 1j47oi9">.css-1j47oi9{background-color:#fff;color:rgba(0, 0, 0, 0.87);-webkit-transition:box-shadow 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:box-shadow 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;box-shadow:0px 2px 4px -1px rgba(0,0,0,0.2),0px 4px 5px 0px rgba(0,0,0,0.14),0px 1px 10px 0px rgba(0,0,0,0.12);display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;width:100%;box-sizing:border-box;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;position:fixed;z-index:1100;top:0;left:auto;right:0;background-color:#1976d2;color:#fff;background-color:#f9f9f9;border-bottom:1px solid #e5e5e5;box-shadow:0px 1px 6px rgba(0, 0, 0, 0.08);height:7rem;}@media print{.css-1j47oi9{}}</style><header class="MuiPaper-root MuiPaper-elevation MuiPaper-elevation4 MuiAppBar-root MuiAppBar-colorPrimary MuiAppBar-positionFixed mui-fixed css-1j47oi9"><style data-emotion="css 1032a1q">.css-1032a1q{-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;height:2rem;background-color:#15005B;background-image:url(https://static.pingcap.com/files/2023/11/15190759/20231116-105219.png);-webkit-background-position:bottom left;background-position:bottom left;-webkit-background-size:400px auto;background-size:400px auto;background-repeat:no-repeat;}</style><div class="MuiBox-root css-1032a1q"><style data-emotion="css 1hx48od">.css-1hx48od{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-flex-wrap:nowrap;-webkit-flex-wrap:nowrap;-ms-flex-wrap:nowrap;flex-wrap:nowrap;-webkit-text-decoration:none;text-decoration:none;color:#fff;height:100%;padding-left:16px;padding-right:16px;}.css-1hx48od&gt;:not(style)+:not(style){margin:0;margin-left:16px;}@media (max-width:899.95px){.css-1hx48od{padding-left:8px;padding-right:8px;}}</style><a href="https://asktug.com/t/topic/1019364" target="_blank" class="css-1hx48od"><style data-emotion="css 1abzdwk">.css-1abzdwk{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;}.css-1abzdwk&gt;:not(style)+:not(style){margin:0;margin-left:16px;}</style><div class="css-1abzdwk"><style data-emotion="css 9lngr5">.css-9lngr5{width:1.25rem;height:1.25rem;}</style><img class="MuiBox-root css-9lngr5" alt="TiDB" src="data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTYiIGhlaWdodD0iMTgiIHZpZXdCb3g9IjAgMCAxNiAxOCIgZmlsbD0ibm9uZSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj4KPHBhdGggZD0iTTcuNjE5NDggMEwwIDQuNDk3NThWMTMuNTAyNEw3LjYxOTQ4IDE4TDE1LjIzOSAxMy41MDI0VjQuNDk3NThMNy42MTk0OCAwWk03LjYxOTQ4IDUuOTk2NzhWMTUuMDAxNkw1LjA4NTk1IDEzLjUxMjFWNy40ODYzTDIuNTUyNDMgOC45ODU0OVY1Ljk5Njc4TDcuNjEwMDIgMy4wMDgwNkwxMC4xNDM1IDQuNTA3MjVMNy42MTk0OCA1Ljk5Njc4Wk0xMi43MDU0IDEyLjAwMzJMMTAuMTYyNSAxMy41MDI0VjcuNTA1NjRMMTIuNzA1NCA2LjAwNjQ1VjEyLjAwMzJaIiBmaWxsPSJ3aGl0ZSIvPgo8L3N2Zz4K"/><style data-emotion="css 1sdiwjr">.css-1sdiwjr{margin:0;font-size:0.875rem;line-height:1.25rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;color:inherit;}</style><span class="MuiTypography-root MuiTypography-body2 css-1sdiwjr">2024 TiDB 文档挑战赛</span></div><style data-emotion="css 1hdswbx">.css-1hdswbx{margin:0;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;border-width:0;border-style:solid;border-color:rgba(0, 0, 0, 0.12);border-bottom-width:0;margin-top:8px;margin-bottom:8px;height:auto;border-right-width:thin;-webkit-align-self:stretch;-ms-flex-item-align:stretch;align-self:stretch;display:initial;border-color:#fff;border-right-width:1.5px;height:0.875rem;-webkit-align-self:auto;-ms-flex-item-align:auto;align-self:auto;}@media (max-width:899.95px){.css-1hdswbx{;}}</style><hr class="MuiDivider-root MuiDivider-middle MuiDivider-vertical MuiDivider-flexItem css-1hdswbx"/><style data-emotion="css nwnren">.css-nwnren{margin:0;font-size:0.875rem;line-height:1.25rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;color:inherit;display:initial;}@media (max-width:899.95px){.css-nwnren{;}}</style><span class="MuiTypography-root MuiTypography-body2 css-nwnren">1/9 - 1/12</span><hr class="MuiDivider-root MuiDivider-middle MuiDivider-vertical MuiDivider-flexItem css-1hdswbx"/><span class="MuiTypography-root MuiTypography-body2 css-nwnren">提 PR 或 Issue 来赢取 Bose 耳机、机械键盘等奖品吧！</span></a></div><style data-emotion="css 1xw2ef0">.css-1xw2ef0{position:relative;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:16px;padding-right:16px;min-height:56px;height:100%;}@media (min-width:600px){.css-1xw2ef0{padding-left:24px;padding-right:24px;}}@media (min-width:0px){@media (orientation: landscape){.css-1xw2ef0{min-height:48px;}}}@media (min-width:600px){.css-1xw2ef0{min-height:64px;}}@media (min-width:900px){.css-1xw2ef0{padding-left:2rem;padding-right:2rem;}}</style><div class="MuiToolbar-root MuiToolbar-gutters MuiToolbar-regular css-1xw2ef0"><style data-emotion="css 16bbyrv">.css-16bbyrv{text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;}.css-16bbyrv:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-16bbyrv:hover{background-color:transparent;}}.css-16bbyrv.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}@media (min-width:1200px){.css-16bbyrv{;}}</style><style data-emotion="css iuftj9">.css-iuftj9{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;}.css-iuftj9::-moz-focus-inner{border-style:none;}.css-iuftj9.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-iuftj9{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-iuftj9:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-iuftj9:hover{background-color:transparent;}}.css-iuftj9.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}@media (min-width:1200px){.css-iuftj9{;}}</style><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeMedium css-iuftj9" tabindex="0" type="button" aria-label="menu"><style data-emotion="css vubbuv">.css-vubbuv{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-vubbuv" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="MenuIcon"><path d="M3 18h18v-2H3v2zm0-5h18v-2H3v2zm0-7v2h18V6H3z"/></svg></button><style data-emotion="css a3xyjy">.css-a3xyjy{z-index:1200;}</style><style data-emotion="css 13tqxrv">@media (min-width:0px){.css-13tqxrv{;}}@media (min-width:900px){.css-13tqxrv{display:block;}}</style><div class="MuiBox-root css-13tqxrv"><style data-emotion="css tx8jsd">.css-tx8jsd{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;}</style><a class="MuiTypography-root MuiTypography-body1 css-tx8jsd" target="_blank" href="https://cn.pingcap.com/" style="text-decoration:none"><style data-emotion="css uz5bjn">.css-uz5bjn{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;width:6.75rem;}@media (min-width:0px){.css-uz5bjn{;}}@media (min-width:600px){.css-uz5bjn{display:block;}}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-uz5bjn" focusable="false" aria-hidden="true" viewbox="0 0 769.89 203.08"><g id="Layer_2" data-name="Layer 2"><g id="Layer_1-2" data-name="Layer 1"><path fill="#082265" d="M100.11,47.34l-88-25.1A9.5,9.5,0,0,0,0,31.38v162.2a9.51,9.51,0,0,0,9.48,9.5,9.35,9.35,0,0,0,2.22-.26l88-21h0a9.48,9.48,0,0,0,7.3-9.25V56.48A9.54,9.54,0,0,0,100.11,47.34Z"/><path fill="#00aeef" d="M160.05,41.57a9.55,9.55,0,0,0-6.88-9.11L41.16.37A9.5,9.5,0,0,0,29,9.51V132.59a9.47,9.47,0,0,0,11.72,9.23l112.14-27a9.47,9.47,0,0,0,7.28-9.26Z"/><path fill="#303eab" d="M100.11,47.34,29,27.07V132.59a9.47,9.47,0,0,0,11.72,9.23L107,125.88V56.48A9.54,9.54,0,0,0,100.11,47.34Z"/><path fill="#082265" d="M576.1,126.26h0l-.23.37a40.12,40.12,0,0,1-13.72,13.09,36.62,36.62,0,0,1-18.78,5.43c-10.94,0-20.51-4.36-28.42-13a43.82,43.82,0,0,1-11.37-31,43.09,43.09,0,0,1,11.74-29.38c7.62-8.17,16.81-12.31,27.3-12.31,14.37-.13,25.2,5.8,33.13,18.13L576,78h.22l9.33-5.77a51.65,51.65,0,0,0-15.42-16.39,48.17,48.17,0,0,0-26.73-8.09A46.85,46.85,0,0,0,507.66,63c-9.94,10.23-15,23.28-15,38.77,0,15,5,28.08,14.84,38.9,9.81,10.64,21.69,16,35.33,16h.51c17.92-.37,32.69-9.06,42.11-24.6Z"/><polygon fill="#082265" points="645.84 49.09 633.16 49.09 586.01 154.63 601.05 154.63 615.63 119.55 615.65 119.55 620.8 108.59 620.78 108.59 639.76 64.05 658.36 108.59 631.66 108.59 626.79 119.55 662.69 119.55 677.4 154.63 690.66 154.63 645.84 49.09"/><path fill="#082265" d="M759.63,58.75c-7-6.32-15.81-9.52-26.18-9.52H699.3v105.4h12.44V113.34h0V102.25h0V60.59H734a24.73,24.73,0,0,1,16.22,5.63,18.12,18.12,0,0,1,7.37,14c.39,6.62-1.77,11.88-6.61,16.07a23.43,23.43,0,0,1-16.31,6H721.77v11.09h14.91a33.34,33.34,0,0,0,23.23-8.85,29,29,0,0,0,10-21.91C770,72.89,766.58,64.87,759.63,58.75Z"/><rect fill="#082265" x="296.25" y="51.17" width="12.44" height="12.44"/><rect fill="#082265" x="296.25" y="79.04" width="12.44" height="75.74"/><path fill="#082265" d="M483.63,147.21V114.69a38.6,38.6,0,0,0-12.25-29.2c-8.22-8.22-18.1-12.27-29.35-12a39.17,39.17,0,0,0-27.82,12.54,40.08,40.08,0,0,0-11.29,28.49,41,41,0,0,0,12.24,29.59c8.19,8.18,18,12.12,29.22,11.71a38.78,38.78,0,0,0,27.48-12.33v5.17m0,0c0,6.88-2.73,12.89-8.11,17.88a27.1,27.1,0,0,1-19,7.73,27.83,27.83,0,0,1-16.93-5.64,25.92,25.92,0,0,1-9-10.54l-9.52,5.5a36.63,36.63,0,0,0,9.94,12c6.6,5.25,14.75,8.13,24.23,8.54.59,0,1.18,0,1.77,0a40.89,40.89,0,0,0,26-9.25c8.17-6.52,12.32-14.86,12.32-24.8v-2.95m-12-31.74a29.23,29.23,0,0,1-8.41,20.22,25.68,25.68,0,0,1-19.5,8.38,27.3,27.3,0,0,1-20.2-8.39,28.22,28.22,0,0,1-8.66-20.34,28.66,28.66,0,0,1,7.88-20.61,27.21,27.21,0,0,1,19.53-9.45c.51,0,1,0,1.5,0,7.61,0,14,2.85,19.45,8.69A28.51,28.51,0,0,1,471.59,115.47Z"/><path fill="#082265" d="M274.1,58.75c-7-6.32-15.81-9.52-26.19-9.52H213.76v105.4h12.45V113.34h0V102.25h0V60.59h22.24a24.73,24.73,0,0,1,16.23,5.63,18.12,18.12,0,0,1,7.37,14c.39,6.62-1.77,11.88-6.61,16.07a23.43,23.43,0,0,1-16.31,6H236.24v11.09h14.91a33.34,33.34,0,0,0,23.23-8.85,29,29,0,0,0,10-21.91C284.5,72.89,281.05,64.87,274.1,58.75Z"/><path fill="#082265" d="M357.54,74.41c-9.92,0-18.3,3.43-24.94,10.2s-9.91,15.24-9.91,25.33v44.53h12V108.86a21.82,21.82,0,0,1,6.75-16.1A22.08,22.08,0,0,1,357.54,86a21.49,21.49,0,0,1,15.82,6.75,21.86,21.86,0,0,1,6.89,16.1v45.61h12V109.94c0-10.09-3.34-18.61-9.92-25.33A33.47,33.47,0,0,0,357.54,74.41Z"/></g></g></svg></a></div><style data-emotion="css 5qlh60">.css-5qlh60{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;padding-left:2rem;height:100%;}.css-5qlh60&gt;:not(style)+:not(style){margin:0;margin-left:24px;}@media (min-width:0px){.css-5qlh60{;}}@media (min-width:900px){.css-5qlh60{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;}}</style><div class="css-5qlh60"><style data-emotion="css kiou0g">.css-kiou0g{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="MuiBox-root css-kiou0g"><a style="text-decoration:none" hreflang="zh" href="/zh/"><style data-emotion="css 2jgwiy">.css-2jgwiy{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;color:#282a36;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,"IBM Plex Sans",sans-serif,"Apple Color Emoji","Segoe UI Emoji";display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;gap:4px;}</style><div class="MuiTypography-root MuiTypography-body1 css-2jgwiy">文档中心</div></a></div><div class="MuiBox-root css-kiou0g"><a style="text-decoration:none" hreflang="zh" href="/zh/tidb/stable"><div class="MuiTypography-root MuiTypography-body1 css-2jgwiy">TiDB</div></a></div><div class="MuiBox-root css-kiou0g"><a class="MuiTypography-root MuiTypography-body1 css-tx8jsd" target="_blank" href="https://asktug.com/" style="text-decoration:none"><div class="MuiTypography-root MuiTypography-body1 css-2jgwiy">社区</div></a></div><div class="MuiBox-root css-kiou0g"><a class="MuiTypography-root MuiTypography-body1 css-tx8jsd" target="_blank" href="https://cn.pingcap.com/contact/" style="text-decoration:none"><div class="MuiTypography-root MuiTypography-body1 css-2jgwiy">联系我们</div></a></div><div class="MuiBox-root css-kiou0g"><a class="MuiTypography-root MuiTypography-body1 css-tx8jsd" target="_blank" href="https://cn.pingcap.com/product/#SelectProduct" style="text-decoration:none"><div class="MuiTypography-root MuiTypography-body1 css-2jgwiy"><style data-emotion="css xnd31y">.css-xnd31y{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:inherit;padding-top:0.5rem;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-xnd31y" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="DownloadIcon"><path d="M5 20h14v-2H5v2zM19 9h-4V3H9v6H5l7 7 7-7z"/></svg></div></a></div></div><style data-emotion="css 1vn3uc0">.css-1vn3uc0{color:#282a36;}@media (min-width:900px){.css-1vn3uc0{;}}</style><div class="MuiBox-root css-1vn3uc0"><style data-emotion="css btg76o">.css-btg76o{text-transform:none;font-family:-apple-system,"Poppins","Helvetica Neue",sans-serif,"Noto Sans","Fira Code","IBM Plex Sans","sans-serif";font-weight:500;font-size:0.875rem;line-height:1.75;min-width:64px;padding:6px 8px;border-radius:4px;-webkit-transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:inherit;border-color:currentColor;box-shadow:none;}.css-btg76o:hover{-webkit-text-decoration:none;text-decoration:none;background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-btg76o:hover{background-color:transparent;}}.css-btg76o.Mui-disabled{color:rgba(0, 0, 0, 0.26);}.css-btg76o:hover{box-shadow:none;}.css-btg76o.Mui-focusVisible{box-shadow:none;}.css-btg76o:active{box-shadow:none;}.css-btg76o.Mui-disabled{box-shadow:none;}</style><style data-emotion="css 1ei260h">.css-1ei260h{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-transform:none;font-family:-apple-system,"Poppins","Helvetica Neue",sans-serif,"Noto Sans","Fira Code","IBM Plex Sans","sans-serif";font-weight:500;font-size:0.875rem;line-height:1.75;min-width:64px;padding:6px 8px;border-radius:4px;-webkit-transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:inherit;border-color:currentColor;box-shadow:none;}.css-1ei260h::-moz-focus-inner{border-style:none;}.css-1ei260h.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-1ei260h{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-1ei260h:hover{-webkit-text-decoration:none;text-decoration:none;background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-1ei260h:hover{background-color:transparent;}}.css-1ei260h.Mui-disabled{color:rgba(0, 0, 0, 0.26);}.css-1ei260h:hover{box-shadow:none;}.css-1ei260h.Mui-focusVisible{box-shadow:none;}.css-1ei260h:active{box-shadow:none;}.css-1ei260h.Mui-disabled{box-shadow:none;}</style><button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textInherit MuiButton-sizeMedium MuiButton-textSizeMedium MuiButton-colorInherit MuiButton-disableElevation css-1ei260h" tabindex="0" type="button" id="header-nav-items" aria-haspopup="true"><style data-emotion="css 6xugel">.css-6xugel{display:inherit;margin-right:8px;margin-left:-4px;}.css-6xugel&gt;*:nth-of-type(1){font-size:20px;}</style><span class="MuiButton-startIcon MuiButton-iconSizeMedium css-6xugel"><style data-emotion="css 1x9zct">.css-1x9zct{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;width:6.75rem;height:1.5rem;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-1x9zct" focusable="false" aria-hidden="true" viewbox="0 0 769.89 203.08"><g id="Layer_2" data-name="Layer 2"><g id="Layer_1-2" data-name="Layer 1"><path fill="#082265" d="M100.11,47.34l-88-25.1A9.5,9.5,0,0,0,0,31.38v162.2a9.51,9.51,0,0,0,9.48,9.5,9.35,9.35,0,0,0,2.22-.26l88-21h0a9.48,9.48,0,0,0,7.3-9.25V56.48A9.54,9.54,0,0,0,100.11,47.34Z"/><path fill="#00aeef" d="M160.05,41.57a9.55,9.55,0,0,0-6.88-9.11L41.16.37A9.5,9.5,0,0,0,29,9.51V132.59a9.47,9.47,0,0,0,11.72,9.23l112.14-27a9.47,9.47,0,0,0,7.28-9.26Z"/><path fill="#303eab" d="M100.11,47.34,29,27.07V132.59a9.47,9.47,0,0,0,11.72,9.23L107,125.88V56.48A9.54,9.54,0,0,0,100.11,47.34Z"/><path fill="#082265" d="M576.1,126.26h0l-.23.37a40.12,40.12,0,0,1-13.72,13.09,36.62,36.62,0,0,1-18.78,5.43c-10.94,0-20.51-4.36-28.42-13a43.82,43.82,0,0,1-11.37-31,43.09,43.09,0,0,1,11.74-29.38c7.62-8.17,16.81-12.31,27.3-12.31,14.37-.13,25.2,5.8,33.13,18.13L576,78h.22l9.33-5.77a51.65,51.65,0,0,0-15.42-16.39,48.17,48.17,0,0,0-26.73-8.09A46.85,46.85,0,0,0,507.66,63c-9.94,10.23-15,23.28-15,38.77,0,15,5,28.08,14.84,38.9,9.81,10.64,21.69,16,35.33,16h.51c17.92-.37,32.69-9.06,42.11-24.6Z"/><polygon fill="#082265" points="645.84 49.09 633.16 49.09 586.01 154.63 601.05 154.63 615.63 119.55 615.65 119.55 620.8 108.59 620.78 108.59 639.76 64.05 658.36 108.59 631.66 108.59 626.79 119.55 662.69 119.55 677.4 154.63 690.66 154.63 645.84 49.09"/><path fill="#082265" d="M759.63,58.75c-7-6.32-15.81-9.52-26.18-9.52H699.3v105.4h12.44V113.34h0V102.25h0V60.59H734a24.73,24.73,0,0,1,16.22,5.63,18.12,18.12,0,0,1,7.37,14c.39,6.62-1.77,11.88-6.61,16.07a23.43,23.43,0,0,1-16.31,6H721.77v11.09h14.91a33.34,33.34,0,0,0,23.23-8.85,29,29,0,0,0,10-21.91C770,72.89,766.58,64.87,759.63,58.75Z"/><rect fill="#082265" x="296.25" y="51.17" width="12.44" height="12.44"/><rect fill="#082265" x="296.25" y="79.04" width="12.44" height="75.74"/><path fill="#082265" d="M483.63,147.21V114.69a38.6,38.6,0,0,0-12.25-29.2c-8.22-8.22-18.1-12.27-29.35-12a39.17,39.17,0,0,0-27.82,12.54,40.08,40.08,0,0,0-11.29,28.49,41,41,0,0,0,12.24,29.59c8.19,8.18,18,12.12,29.22,11.71a38.78,38.78,0,0,0,27.48-12.33v5.17m0,0c0,6.88-2.73,12.89-8.11,17.88a27.1,27.1,0,0,1-19,7.73,27.83,27.83,0,0,1-16.93-5.64,25.92,25.92,0,0,1-9-10.54l-9.52,5.5a36.63,36.63,0,0,0,9.94,12c6.6,5.25,14.75,8.13,24.23,8.54.59,0,1.18,0,1.77,0a40.89,40.89,0,0,0,26-9.25c8.17-6.52,12.32-14.86,12.32-24.8v-2.95m-12-31.74a29.23,29.23,0,0,1-8.41,20.22,25.68,25.68,0,0,1-19.5,8.38,27.3,27.3,0,0,1-20.2-8.39,28.22,28.22,0,0,1-8.66-20.34,28.66,28.66,0,0,1,7.88-20.61,27.21,27.21,0,0,1,19.53-9.45c.51,0,1,0,1.5,0,7.61,0,14,2.85,19.45,8.69A28.51,28.51,0,0,1,471.59,115.47Z"/><path fill="#082265" d="M274.1,58.75c-7-6.32-15.81-9.52-26.19-9.52H213.76v105.4h12.45V113.34h0V102.25h0V60.59h22.24a24.73,24.73,0,0,1,16.23,5.63,18.12,18.12,0,0,1,7.37,14c.39,6.62-1.77,11.88-6.61,16.07a23.43,23.43,0,0,1-16.31,6H236.24v11.09h14.91a33.34,33.34,0,0,0,23.23-8.85,29,29,0,0,0,10-21.91C284.5,72.89,281.05,64.87,274.1,58.75Z"/><path fill="#082265" d="M357.54,74.41c-9.92,0-18.3,3.43-24.94,10.2s-9.91,15.24-9.91,25.33v44.53h12V108.86a21.82,21.82,0,0,1,6.75-16.1A22.08,22.08,0,0,1,357.54,86a21.49,21.49,0,0,1,15.82,6.75,21.86,21.86,0,0,1,6.89,16.1v45.61h12V109.94c0-10.09-3.34-18.61-9.92-25.33A33.47,33.47,0,0,0,357.54,74.41Z"/></g></g></svg></span><style data-emotion="css 1n4a93h">.css-1n4a93h{display:inherit;margin-right:-4px;margin-left:8px;}.css-1n4a93h&gt;*:nth-of-type(1){font-size:20px;}</style><span class="MuiButton-endIcon MuiButton-iconSizeMedium css-1n4a93h"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-vubbuv" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="KeyboardArrowDownIcon"><path d="M7.41 8.59 12 13.17l4.59-4.58L18 10l-6 6-6-6 1.41-1.41z"/></svg></span></button></div><style data-emotion="css jnv64h">.css-jnv64h{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;margin-left:auto;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;}@media (min-width:0px){.css-jnv64h&gt;:not(style)+:not(style){margin:0;margin-left:8px;}}@media (min-width:1200px){.css-jnv64h&gt;:not(style)+:not(style){margin:0;margin-left:24px;}}</style><div class="css-jnv64h"><style data-emotion="css 1qlh2t1">.css-1qlh2t1{color:#282a36;}</style><div class="MuiBox-root css-1qlh2t1"><style data-emotion="css 1mvsusm">.css-1mvsusm{text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:inherit;}.css-1mvsusm:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-1mvsusm:hover{background-color:transparent;}}.css-1mvsusm.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}@media (min-width:1200px){.css-1mvsusm{;}}</style><style data-emotion="css jwr93t">.css-jwr93t{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:inherit;}.css-jwr93t::-moz-focus-inner{border-style:none;}.css-jwr93t.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-jwr93t{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-jwr93t:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-jwr93t:hover{background-color:transparent;}}.css-jwr93t.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}@media (min-width:1200px){.css-jwr93t{;}}</style><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeMedium css-jwr93t" tabindex="0" type="button"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-vubbuv" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="LanguageIcon"><path d="M11.99 2C6.47 2 2 6.48 2 12s4.47 10 9.99 10C17.52 22 22 17.52 22 12S17.52 2 11.99 2zm6.93 6h-2.95c-.32-1.25-.78-2.45-1.38-3.56 1.84.63 3.37 1.91 4.33 3.56zM12 4.04c.83 1.2 1.48 2.53 1.91 3.96h-3.82c.43-1.43 1.08-2.76 1.91-3.96zM4.26 14C4.1 13.36 4 12.69 4 12s.1-1.36.26-2h3.38c-.08.66-.14 1.32-.14 2 0 .68.06 1.34.14 2H4.26zm.82 2h2.95c.32 1.25.78 2.45 1.38 3.56-1.84-.63-3.37-1.9-4.33-3.56zm2.95-8H5.08c.96-1.66 2.49-2.93 4.33-3.56C8.81 5.55 8.35 6.75 8.03 8zM12 19.96c-.83-1.2-1.48-2.53-1.91-3.96h3.82c-.43 1.43-1.08 2.76-1.91 3.96zM14.34 14H9.66c-.09-.66-.16-1.32-.16-2 0-.68.07-1.35.16-2h4.68c.09.65.16 1.32.16 2 0 .68-.07 1.34-.16 2zm.25 5.56c.6-1.11 1.06-2.31 1.38-3.56h2.95c-.96 1.65-2.49 2.93-4.33 3.56zM16.36 14c.08-.66.14-1.32.14-2 0-.68-.06-1.34-.14-2h3.38c.16.64.26 1.31.26 2s-.1 1.36-.26 2h-3.38z"/></svg></button><style data-emotion="css t5gsfy">.css-t5gsfy{text-transform:none;font-family:-apple-system,"Poppins","Helvetica Neue",sans-serif,"Noto Sans","Fira Code","IBM Plex Sans","sans-serif";font-weight:500;font-size:0.875rem;line-height:1.75;min-width:64px;padding:6px 8px;border-radius:4px;-webkit-transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:inherit;border-color:currentColor;box-shadow:none;}.css-t5gsfy:hover{-webkit-text-decoration:none;text-decoration:none;background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-t5gsfy:hover{background-color:transparent;}}.css-t5gsfy.Mui-disabled{color:rgba(0, 0, 0, 0.26);}.css-t5gsfy:hover{box-shadow:none;}.css-t5gsfy.Mui-focusVisible{box-shadow:none;}.css-t5gsfy:active{box-shadow:none;}.css-t5gsfy.Mui-disabled{box-shadow:none;}@media (min-width:0px){.css-t5gsfy{;}}@media (min-width:1200px){.css-t5gsfy{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;}}</style><style data-emotion="css 1csz7wa">.css-1csz7wa{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-transform:none;font-family:-apple-system,"Poppins","Helvetica Neue",sans-serif,"Noto Sans","Fira Code","IBM Plex Sans","sans-serif";font-weight:500;font-size:0.875rem;line-height:1.75;min-width:64px;padding:6px 8px;border-radius:4px;-webkit-transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:inherit;border-color:currentColor;box-shadow:none;}.css-1csz7wa::-moz-focus-inner{border-style:none;}.css-1csz7wa.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-1csz7wa{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-1csz7wa:hover{-webkit-text-decoration:none;text-decoration:none;background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-1csz7wa:hover{background-color:transparent;}}.css-1csz7wa.Mui-disabled{color:rgba(0, 0, 0, 0.26);}.css-1csz7wa:hover{box-shadow:none;}.css-1csz7wa.Mui-focusVisible{box-shadow:none;}.css-1csz7wa:active{box-shadow:none;}.css-1csz7wa.Mui-disabled{box-shadow:none;}@media (min-width:0px){.css-1csz7wa{;}}@media (min-width:1200px){.css-1csz7wa{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;}}</style><button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textInherit MuiButton-sizeMedium MuiButton-textSizeMedium MuiButton-colorInherit MuiButton-disableElevation css-1csz7wa" tabindex="0" type="button" id="header-lang-switch" aria-haspopup="true"><span class="MuiButton-startIcon MuiButton-iconSizeMedium css-6xugel"><style data-emotion="css 1slalk2">.css-1slalk2{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;fill:#282a36;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-1slalk2" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="LanguageIcon"><path d="M11.99 2C6.47 2 2 6.48 2 12s4.47 10 9.99 10C17.52 22 22 17.52 22 12S17.52 2 11.99 2zm6.93 6h-2.95c-.32-1.25-.78-2.45-1.38-3.56 1.84.63 3.37 1.91 4.33 3.56zM12 4.04c.83 1.2 1.48 2.53 1.91 3.96h-3.82c.43-1.43 1.08-2.76 1.91-3.96zM4.26 14C4.1 13.36 4 12.69 4 12s.1-1.36.26-2h3.38c-.08.66-.14 1.32-.14 2 0 .68.06 1.34.14 2H4.26zm.82 2h2.95c.32 1.25.78 2.45 1.38 3.56-1.84-.63-3.37-1.9-4.33-3.56zm2.95-8H5.08c.96-1.66 2.49-2.93 4.33-3.56C8.81 5.55 8.35 6.75 8.03 8zM12 19.96c-.83-1.2-1.48-2.53-1.91-3.96h3.82c-.43 1.43-1.08 2.76-1.91 3.96zM14.34 14H9.66c-.09-.66-.16-1.32-.16-2 0-.68.07-1.35.16-2h4.68c.09.65.16 1.32.16 2 0 .68-.07 1.34-.16 2zm.25 5.56c.6-1.11 1.06-2.31 1.38-3.56h2.95c-.96 1.65-2.49 2.93-4.33 3.56zM16.36 14c.08-.66.14-1.32.14-2 0-.68-.06-1.34-.14-2h3.38c.16.64.26 1.31.26 2s-.1 1.36-.26 2h-3.38z"/></svg></span><style data-emotion="css 15r93eu">.css-15r93eu{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;color:inherit;}</style><span class="MuiTypography-root MuiTypography-body1 css-15r93eu">语言</span><span class="MuiButton-endIcon MuiButton-iconSizeMedium css-1n4a93h"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-1slalk2" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="KeyboardArrowDownIcon"><path d="M7.41 8.59 12 13.17l4.59-4.58L18 10l-6 6-6-6 1.41-1.41z"/></svg></span></button></div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeMedium css-iuftj9" tabindex="0" type="button"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-vubbuv" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="SearchIcon"><path d="M15.5 14h-.79l-.28-.27C15.41 12.59 16 11.11 16 9.5 16 5.91 13.09 3 9.5 3S3 5.91 3 9.5 5.91 16 9.5 16c1.61 0 3.09-.59 4.23-1.57l.27.28v.79l5 4.99L20.49 19l-4.99-5zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"/></svg></button><style data-emotion="css ahtg4s">.css-ahtg4s{max-width:13rem;}@media (min-width:0px){.css-ahtg4s{;}}@media (min-width:1200px){.css-ahtg4s{display:block;}}</style><form class="MuiBox-root css-ahtg4s" novalidate="" autocomplete="off"><style data-emotion="css 24u6h2">.css-24u6h2 .MuiOutlinedInput-root:hover fieldset{border-color:#0ca6f2;border-width:1px;}.css-24u6h2 .MuiOutlinedInput-root.Mui-focused fieldset{border-color:#0ca6f2;border-width:1px;}</style><style data-emotion="css fzbqas">.css-fzbqas .MuiOutlinedInput-root:hover fieldset{border-color:#0ca6f2;border-width:1px;}.css-fzbqas .MuiOutlinedInput-root.Mui-focused fieldset{border-color:#0ca6f2;border-width:1px;}</style><style data-emotion="css bj7gct">.css-bj7gct{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;position:relative;min-width:0;padding:0;margin:0;border:0;vertical-align:top;width:100%;}.css-bj7gct .MuiOutlinedInput-root:hover fieldset{border-color:#0ca6f2;border-width:1px;}.css-bj7gct .MuiOutlinedInput-root.Mui-focused fieldset{border-color:#0ca6f2;border-width:1px;}</style><div class="MuiFormControl-root MuiFormControl-fullWidth MuiTextField-root css-bj7gct"><style data-emotion="css-global 1prfaxn">@-webkit-keyframes mui-auto-fill{from{display:block;}}@keyframes mui-auto-fill{from{display:block;}}@-webkit-keyframes mui-auto-fill-cancel{from{display:block;}}@keyframes mui-auto-fill-cancel{from{display:block;}}</style><style data-emotion="css sv5gtw">.css-sv5gtw{font-size:1rem;line-height:1.4375em;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:rgba(0, 0, 0, 0.87);box-sizing:border-box;position:relative;cursor:text;display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;width:100%;position:relative;border-radius:4px;padding-left:14px;background:#fff;}.css-sv5gtw.Mui-disabled{color:rgba(0, 0, 0, 0.38);cursor:default;}.css-sv5gtw:hover .MuiOutlinedInput-notchedOutline{border-color:rgba(0, 0, 0, 0.87);}@media (hover: none){.css-sv5gtw:hover .MuiOutlinedInput-notchedOutline{border-color:rgba(0, 0, 0, 0.23);}}.css-sv5gtw.Mui-focused .MuiOutlinedInput-notchedOutline{border-color:#1976d2;border-width:2px;}.css-sv5gtw.Mui-error .MuiOutlinedInput-notchedOutline{border-color:#d32f2f;}.css-sv5gtw.Mui-disabled .MuiOutlinedInput-notchedOutline{border-color:rgba(0, 0, 0, 0.26);}</style><div class="MuiInputBase-root MuiOutlinedInput-root MuiInputBase-colorPrimary MuiInputBase-fullWidth MuiInputBase-formControl MuiInputBase-sizeSmall MuiInputBase-adornedStart css-sv5gtw"><style data-emotion="css 1a6giau">.css-1a6giau{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;height:0.01em;max-height:2em;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;white-space:nowrap;color:rgba(0, 0, 0, 0.54);margin-right:8px;}</style><div class="MuiInputAdornment-root MuiInputAdornment-positionStart MuiInputAdornment-outlined MuiInputAdornment-sizeSmall css-1a6giau"><span class="notranslate"></span><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-vubbuv" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="SearchIcon"><path d="M15.5 14h-.79l-.28-.27C15.41 12.59 16 11.11 16 9.5 16 5.91 13.09 3 9.5 3S3 5.91 3 9.5 5.91 16 9.5 16c1.61 0 3.09-.59 4.23-1.57l.27.28v.79l5 4.99L20.49 19l-4.99-5zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"/></svg></div><style data-emotion="css f2zrvi">.css-f2zrvi{font:inherit;letter-spacing:inherit;color:currentColor;padding:4px 0 5px;border:0;box-sizing:content-box;background:none;height:1.4375em;margin:0;-webkit-tap-highlight-color:transparent;display:block;min-width:0;width:100%;-webkit-animation-name:mui-auto-fill-cancel;animation-name:mui-auto-fill-cancel;-webkit-animation-duration:10ms;animation-duration:10ms;padding-top:1px;-moz-appearance:textfield;padding:8.5px 14px;padding-left:0;}.css-f2zrvi::-webkit-input-placeholder{color:currentColor;opacity:0.42;-webkit-transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;}.css-f2zrvi::-moz-placeholder{color:currentColor;opacity:0.42;-webkit-transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;}.css-f2zrvi:-ms-input-placeholder{color:currentColor;opacity:0.42;-webkit-transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;}.css-f2zrvi::-ms-input-placeholder{color:currentColor;opacity:0.42;-webkit-transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:opacity 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;}.css-f2zrvi:focus{outline:0;}.css-f2zrvi:invalid{box-shadow:none;}.css-f2zrvi::-webkit-search-decoration{-webkit-appearance:none;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi::-webkit-input-placeholder{opacity:0!important;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi::-moz-placeholder{opacity:0!important;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi:-ms-input-placeholder{opacity:0!important;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi::-ms-input-placeholder{opacity:0!important;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi:focus::-webkit-input-placeholder{opacity:0.42;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi:focus::-moz-placeholder{opacity:0.42;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi:focus:-ms-input-placeholder{opacity:0.42;}label[data-shrink=false]+.MuiInputBase-formControl .css-f2zrvi:focus::-ms-input-placeholder{opacity:0.42;}.css-f2zrvi.Mui-disabled{opacity:1;-webkit-text-fill-color:rgba(0, 0, 0, 0.38);}.css-f2zrvi:-webkit-autofill{-webkit-animation-duration:5000s;animation-duration:5000s;-webkit-animation-name:mui-auto-fill;animation-name:mui-auto-fill;}.css-f2zrvi:-webkit-autofill{border-radius:inherit;}</style><input type="search" aria-invalid="false" id="doc-search" placeholder="搜索文档" value="" class="MuiInputBase-input MuiOutlinedInput-input MuiInputBase-inputTypeSearch MuiInputBase-inputSizeSmall MuiInputBase-inputAdornedStart css-f2zrvi"/><style data-emotion="css 19w1uun">.css-19w1uun{border-color:rgba(0, 0, 0, 0.23);}</style><style data-emotion="css igs3ac">.css-igs3ac{text-align:left;bottom:0;right:0;top:-5px;left:0;margin:0;padding:0 8px;pointer-events:none;border-radius:inherit;border-style:solid;border-width:1px;overflow:hidden;min-width:0%;border-color:rgba(0, 0, 0, 0.23);}</style><fieldset aria-hidden="true" class="MuiOutlinedInput-notchedOutline css-igs3ac"><style data-emotion="css hdw1oc">.css-hdw1oc{float:unset;overflow:hidden;padding:0;line-height:11px;-webkit-transition:width 150ms cubic-bezier(0.0, 0, 0.2, 1) 0ms;transition:width 150ms cubic-bezier(0.0, 0, 0.2, 1) 0ms;}</style><legend class="css-hdw1oc"><span class="notranslate"></span></legend></fieldset></div></div></form></div></div></header><style data-emotion="css o1nacy">.css-o1nacy{margin-top:7rem;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;}</style><div class="PingCAP-Doc MuiBox-root css-o1nacy"><style data-emotion="css hboir5">.css-hboir5{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;width:100%;}</style><div class="MuiBox-root css-hboir5"><style data-emotion="css 2tzg8">.css-2tzg8{width:18.75rem;border-right:1px solid #E5E4E4;}@media (min-width:0px){.css-2tzg8{;}}@media (min-width:1200px){.css-2tzg8{display:block;}}</style><aside class="MuiBox-root css-2tzg8"><style data-emotion="css 1eohm8p">.css-1eohm8p{position:-webkit-sticky;position:sticky;top:5rem;height:100%;max-height:calc(100vh - 7rem);overflow-y:auto;padding:1rem;}</style><div class="MuiBox-root css-1eohm8p"><style data-emotion="css fmyu0n">.css-fmyu0n{text-transform:none;font-family:-apple-system,"Poppins","Helvetica Neue",sans-serif,"Noto Sans","Fira Code","IBM Plex Sans","sans-serif";font-weight:500;font-size:0.875rem;line-height:1.75;min-width:64px;padding:6px 8px;border-radius:4px;-webkit-transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:#1976d2;width:100%;height:2rem;-webkit-box-pack:justify;-webkit-justify-content:space-between;justify-content:space-between;border-style:solid;border-width:1px;border-color:#e5e5e5;margin-bottom:1rem;}.css-fmyu0n:hover{-webkit-text-decoration:none;text-decoration:none;background-color:rgba(25, 118, 210, 0.04);}@media (hover: none){.css-fmyu0n:hover{background-color:transparent;}}.css-fmyu0n.Mui-disabled{color:rgba(0, 0, 0, 0.26);}</style><style data-emotion="css 1rq233s">.css-1rq233s{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-transform:none;font-family:-apple-system,"Poppins","Helvetica Neue",sans-serif,"Noto Sans","Fira Code","IBM Plex Sans","sans-serif";font-weight:500;font-size:0.875rem;line-height:1.75;min-width:64px;padding:6px 8px;border-radius:4px;-webkit-transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,box-shadow 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,border-color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms,color 250ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;color:#1976d2;width:100%;height:2rem;-webkit-box-pack:justify;-webkit-justify-content:space-between;justify-content:space-between;border-style:solid;border-width:1px;border-color:#e5e5e5;margin-bottom:1rem;}.css-1rq233s::-moz-focus-inner{border-style:none;}.css-1rq233s.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-1rq233s{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-1rq233s:hover{-webkit-text-decoration:none;text-decoration:none;background-color:rgba(25, 118, 210, 0.04);}@media (hover: none){.css-1rq233s:hover{background-color:transparent;}}.css-1rq233s.Mui-disabled{color:rgba(0, 0, 0, 0.26);}</style><button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeMedium MuiButton-textSizeMedium css-1rq233s" tabindex="0" type="button" id="version-select-button" aria-haspopup="true"><style data-emotion="css 3cb5vr">.css-3cb5vr{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;padding:0 0.25rem;font-size:0.875rem;line-height:1.25rem;}</style><div class="MuiTypography-root MuiTypography-body1 css-3cb5vr">v5.3</div><style data-emotion="css 1n4a93h">.css-1n4a93h{display:inherit;margin-right:-4px;margin-left:8px;}.css-1n4a93h&gt;*:nth-of-type(1){font-size:20px;}</style><span class="MuiButton-endIcon MuiButton-iconSizeMedium css-1n4a93h"><style data-emotion="css b5l66">.css-b5l66{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;-webkit-transform:rotate(0deg);-moz-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg);height:1.5rem;width:1.5rem;fill:#999999;margin-right:0.25rem;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium css-b5l66" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></span></button><style data-emotion="css 1c58svf">.css-1c58svf .MuiPaper-root{border-radius:6px;margin-top:8px;min-width:268px;color:rgb(55, 65, 81);box-shadow:rgb(255, 255, 255) 0px 0px 0px 0px,rgba(0, 0, 0, 0.05) 0px 0px 0px 1px,rgba(0, 0, 0, 0.1) 0px 10px 15px -3px,rgba(0, 0, 0, 0.05) 0px 4px 6px -2px;}.css-1c58svf .MuiPaper-root .MuiMenu-list{padding:4px 0;}.css-1c58svf .MuiPaper-root .MuiMenuItem-root .MuiSvgIcon-root{font-size:18px;color:rgba(0, 0, 0, 0.6);margin-right:12px;}.css-1c58svf .MuiPaper-root .MuiMenuItem-root:active{background-color:rgba(25, 118, 210, 0.08);}</style><style data-emotion="css yvxbj">.css-yvxbj .MuiPaper-root{border-radius:6px;margin-top:8px;min-width:268px;color:rgb(55, 65, 81);box-shadow:rgb(255, 255, 255) 0px 0px 0px 0px,rgba(0, 0, 0, 0.05) 0px 0px 0px 1px,rgba(0, 0, 0, 0.1) 0px 10px 15px -3px,rgba(0, 0, 0, 0.05) 0px 4px 6px -2px;}.css-yvxbj .MuiPaper-root .MuiMenu-list{padding:4px 0;}.css-yvxbj .MuiPaper-root .MuiMenuItem-root .MuiSvgIcon-root{font-size:18px;color:rgba(0, 0, 0, 0.6);margin-right:12px;}.css-yvxbj .MuiPaper-root .MuiMenuItem-root:active{background-color:rgba(25, 118, 210, 0.08);}</style><style data-emotion="css oe3wem">.css-oe3wem .MuiPaper-root{border-radius:6px;margin-top:8px;min-width:268px;color:rgb(55, 65, 81);box-shadow:rgb(255, 255, 255) 0px 0px 0px 0px,rgba(0, 0, 0, 0.05) 0px 0px 0px 1px,rgba(0, 0, 0, 0.1) 0px 10px 15px -3px,rgba(0, 0, 0, 0.05) 0px 4px 6px -2px;}.css-oe3wem .MuiPaper-root .MuiMenu-list{padding:4px 0;}.css-oe3wem .MuiPaper-root .MuiMenuItem-root .MuiSvgIcon-root{font-size:18px;color:rgba(0, 0, 0, 0.6);margin-right:12px;}.css-oe3wem .MuiPaper-root .MuiMenuItem-root:active{background-color:rgba(25, 118, 210, 0.08);}</style><style data-emotion="css 12mehxg">.css-12mehxg{padding:0;margin:0;list-style:none;outline:0;}</style><ul role="tree" id="left-nav-treeview" aria-multiselectable="false" class="MuiTreeView-root css-12mehxg" tabindex="0" aria-label="left navigation"><style data-emotion="css 1gesgke">.css-1gesgke .MuiTreeItem-content{color:#282a36;border-radius:4px;}.css-1gesgke .MuiTreeItem-content:hover{background-color:#f9f9f9;}.css-1gesgke .MuiTreeItem-content.Mui-selected,.css-1gesgke .MuiTreeItem-content.Mui-selected.Mui-focused{background-color:var(--tree-view-bg-color, #EAF6FB);color:var(--tree-view-color, #0A85C2);}.css-1gesgke .MuiTreeItem-content.Mui-selected svg.MuiTreeItem-ChevronRightIcon,.css-1gesgke .MuiTreeItem-content.Mui-selected.Mui-focused svg.MuiTreeItem-ChevronRightIcon{fill:var(--tree-view-color, #0A85C2);}.css-1gesgke .MuiTreeItem-content.Mui-focused{background-color:#f9f9f9;}.css-1gesgke .MuiTreeItem-content .MuiTreeItem-label{font-weight:inherit;color:inherit;}.css-1gesgke .MuiTreeItem-content .MuiTreeItem-iconContainer{;}.css-1gesgke .MuiTreeItem-group{margin-left:0;}.css-1gesgke .MuiTreeItem-group .MuiTreeItem-content{padding-left:16px;}</style><style data-emotion="css 1oy5rnm">.css-1oy5rnm{list-style:none;margin:0;padding:0;outline:0;}.css-1oy5rnm .MuiTreeItem-content{color:#282a36;border-radius:4px;}.css-1oy5rnm .MuiTreeItem-content:hover{background-color:#f9f9f9;}.css-1oy5rnm .MuiTreeItem-content.Mui-selected,.css-1oy5rnm .MuiTreeItem-content.Mui-selected.Mui-focused{background-color:var(--tree-view-bg-color, #EAF6FB);color:var(--tree-view-color, #0A85C2);}.css-1oy5rnm .MuiTreeItem-content.Mui-selected svg.MuiTreeItem-ChevronRightIcon,.css-1oy5rnm .MuiTreeItem-content.Mui-selected.Mui-focused svg.MuiTreeItem-ChevronRightIcon{fill:var(--tree-view-color, #0A85C2);}.css-1oy5rnm .MuiTreeItem-content.Mui-focused{background-color:#f9f9f9;}.css-1oy5rnm .MuiTreeItem-content .MuiTreeItem-label{font-weight:inherit;color:inherit;}.css-1oy5rnm .MuiTreeItem-content .MuiTreeItem-iconContainer{;}.css-1oy5rnm .MuiTreeItem-group{margin-left:0;}.css-1oy5rnm .MuiTreeItem-group .MuiTreeItem-content{padding-left:16px;}</style><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-0" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><style data-emotion="css khel7y">.css-khel7y{padding:0 8px;width:100%;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;cursor:pointer;-webkit-tap-highlight-color:transparent;}.css-khel7y:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-khel7y:hover{background-color:transparent;}}.css-khel7y.Mui-disabled{opacity:0.38;background-color:transparent;}.css-khel7y.Mui-focused{background-color:rgba(0, 0, 0, 0.12);}.css-khel7y.Mui-selected{background-color:rgba(25, 118, 210, 0.08);}.css-khel7y.Mui-selected:hover{background-color:rgba(25, 118, 210, 0.12);}@media (hover: none){.css-khel7y.Mui-selected:hover{background-color:rgba(25, 118, 210, 0.08);}}.css-khel7y.Mui-selected.Mui-focused{background-color:rgba(25, 118, 210, 0.2);}.css-khel7y .MuiTreeItem-iconContainer{margin-right:4px;width:15px;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;}.css-khel7y .MuiTreeItem-iconContainer svg{font-size:18px;}.css-khel7y .MuiTreeItem-label{width:100%;min-width:0;padding-left:4px;position:relative;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;}</style><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><style data-emotion="css znl8a3">.css-znl8a3{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;min-height:1.75rem;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:0rem;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="css-znl8a3"><style data-emotion="css tx8jsd">.css-tx8jsd{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;}</style><a class="MuiTypography-root MuiTypography-body1 css-tx8jsd" target="_blank" href="https://docs.pingcap.com/zh" style="text-decoration:none;width:100%;color:inherit"><style data-emotion="css 8atqhb">.css-8atqhb{width:100%;}</style><div class="MuiBox-root css-8atqhb"><style data-emotion="css 1hwyipb">.css-1hwyipb{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;color:inherit;font-size:0.875rem;line-height:1.25rem;}</style><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">文档中心</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">关于 TiDB</div></div><style data-emotion="css xjq79n">.css-xjq79n{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;fill:#999999;height:1rem;width:1rem;margin-left:auto;-webkit-transform:none;-moz-transform:none;-ms-transform:none;transform:none;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div><style data-emotion="css 1jozaee">.css-1jozaee{margin:0;padding:0;margin-left:17px;}</style></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">快速上手</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-3" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">部署标准集群</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-4" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">数据迁移</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-5" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">运维操作</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-6" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">监控与告警</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-7" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">故障诊断</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="true" id="left-nav-treeview-0-8" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content Mui-expanded" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">性能调优</div></div><style data-emotion="css 171pefp">.css-171pefp{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;fill:#999999;height:1rem;width:1rem;margin-left:auto;-webkit-transform:rotate(90deg);-moz-transform:rotate(90deg);-ms-transform:rotate(90deg);transform:rotate(90deg);}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-171pefp" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div><style data-emotion="css 1xxsnna">.css-1xxsnna{height:auto;overflow:visible;-webkit-transition:height 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:height 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;margin:0;padding:0;margin-left:17px;}</style><ul class="MuiCollapse-root MuiCollapse-vertical MuiTreeItem-group MuiCollapse-entered css-1xxsnna" style="min-height:0px" role="group"><div class="MuiCollapse-wrapper MuiCollapse-vertical css-hboir5"><div class="MuiCollapse-wrapperInner MuiCollapse-vertical css-8atqhb"><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-8-0" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><style data-emotion="css kb2j4b">.css-kb2j4b{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;min-height:1.75rem;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:0.5rem;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">系统调优</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-8-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">软件调优</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="true" id="left-nav-treeview-0-8-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content Mui-expanded" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">SQL 性能调优</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-171pefp" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div><ul class="MuiCollapse-root MuiCollapse-vertical MuiTreeItem-group MuiCollapse-entered css-1xxsnna" style="min-height:0px" role="group"><div class="MuiCollapse-wrapper MuiCollapse-vertical css-hboir5"><div class="MuiCollapse-wrapperInner MuiCollapse-vertical css-8atqhb"><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-8-2-0" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><style data-emotion="css snygwd">.css-snygwd{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;min-height:1.75rem;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:1rem;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="css-snygwd"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/v5.3/sql-tuning-overview"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">SQL 性能调优概览</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-8-2-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">理解 TiDB 执行计划</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-8-2-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">SQL 优化流程</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="true" id="left-nav-treeview-0-8-2-3" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content Mui-expanded" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">控制执行计划</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-171pefp" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div><ul class="MuiCollapse-root MuiCollapse-vertical MuiTreeItem-group MuiCollapse-entered css-1xxsnna" style="min-height:0px" role="group"><div class="MuiCollapse-wrapper MuiCollapse-vertical css-hboir5"><div class="MuiCollapse-wrapperInner MuiCollapse-vertical css-8atqhb"><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-8-2-3-0" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><style data-emotion="css 5fc025">.css-5fc025{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;min-height:1.75rem;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:1.5rem;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="css-5fc025"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/v5.3/control-execution-plan"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">控制执行计划概览</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-8-2-3-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content Mui-expanded" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-5fc025"><a aria-current="page" style="text-decoration:none;width:100%;color:inherit" class="" href="/zh/tidb/v5.3/optimizer-hints"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">Optimizer Hints</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-8-2-3-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-5fc025"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/v5.3/sql-plan-management"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">执行计划管理</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-8-2-3-3" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-5fc025"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/v5.3/blocklist-control-plan"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">优化规则及表达式下推的黑名单</div></div></a></div></div></div></li></div></div></ul></li></div></div></ul></li></div></div></ul></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-9" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">教程</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-10" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">TiDB 工具</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-11" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">参考指南</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-12" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">常见问题解答 (FAQ)</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">版本发布历史</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-14" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/v5.3/glossary"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">术语表</div></div></a></div></div></div></li></ul></div></aside><style data-emotion="css sb2sd0">.css-sb2sd0{width:100%;}@media (min-width:1200px){.css-sb2sd0{max-width:calc(100% - 18.75rem);}}</style><main class="MuiBox-root css-sb2sd0"><style data-emotion="css 1rnnmjb">.css-1rnnmjb{max-width:1340px;width:100%;margin-left:auto;margin-right:auto;display:block;box-sizing:border-box;}</style><div class="MuiBox-root css-1rnnmjb"><style data-emotion="css 90fn5w">.css-90fn5w{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;}@media (min-width:0px){.css-90fn5w{-webkit-flex-direction:column-reverse;-ms-flex-direction:column-reverse;flex-direction:column-reverse;}}@media (min-width:600px){.css-90fn5w{-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;}}</style><div class="css-90fn5w"><style data-emotion="css vofosd">.css-vofosd{padding:1.5rem 0;}@media (min-width:0px){.css-vofosd{width:100%;}}@media (min-width:600px){.css-vofosd{width:calc(100% - 17.5rem);}}</style><div class="MuiBox-root css-vofosd"><style data-emotion="css 1ekb41w">.css-1ekb41w{width:100%;margin-left:auto;box-sizing:border-box;margin-right:auto;display:block;padding-left:16px;padding-right:16px;}@media (min-width:600px){.css-1ekb41w{padding-left:24px;padding-right:24px;}}@media (min-width:1536px){.css-1ekb41w{max-width:1536px;}}</style><div class="MuiContainer-root MuiContainer-maxWidthXl doc-content css-1ekb41w"><div class="markdown-body MuiBox-root css-0"><style data-emotion="css 1weqspv">.css-1weqspv{padding-top:0.5rem;padding-bottom:0.5rem;}.css-1weqspv .MuiAlert-message p{margin-bottom:0px;margin-top:0px;}</style><div class="MuiBox-root css-1weqspv"><style data-emotion="css 17zlexa">.css-17zlexa{font-size:0.875rem;line-height:1.25rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:rgb(1, 67, 97);background-color:rgb(229, 246, 253);display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;padding:6px 16px;}.css-17zlexa .MuiAlert-icon{color:#03a9f4;}</style><style data-emotion="css 152gid5">.css-152gid5{background-color:#fff;color:rgba(0, 0, 0, 0.87);-webkit-transition:box-shadow 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:box-shadow 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;border-radius:4px;box-shadow:none;font-size:0.875rem;line-height:1.25rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:rgb(1, 67, 97);background-color:rgb(229, 246, 253);display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;padding:6px 16px;}.css-152gid5 .MuiAlert-icon{color:#03a9f4;}</style><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><style data-emotion="css 1l54tgj">.css-1l54tgj{margin-right:12px;padding:7px 0;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;font-size:22px;opacity:0.9;}</style><div class="MuiAlert-icon css-1l54tgj"><style data-emotion="css 1cw4hi4">.css-1cw4hi4{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:inherit;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><style data-emotion="css 1xsto0d">.css-1xsto0d{padding:8px 0;min-width:0;overflow:auto;}</style><div class="MuiAlert-message css-1xsto0d"><style data-emotion="css 1h2y6o4">.css-1h2y6o4{font-weight:500;margin-top:-2px;}</style><style data-emotion="css 17ioyuk">.css-17ioyuk{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;margin-bottom:0.35em;font-weight:500;margin-top:-2px;}</style><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">重要</div><p class="MuiTypography-root MuiTypography-body1 css-tx8jsd">你正在查看 TiDB 数据库的较旧版本 (TiDB v5.3) 的文档。如无特殊需求，建议使用 TiDB 数据库的<a hreflang="zh" href="/zh/tidb/stable/optimizer-hints">最新 LTS 版本</a>。</p></div></div></div><h1 id="optimizer-hints" style="position:relative"><a href="#optimizer-hints" aria-label="optimizer hints permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Optimizer Hints</h1><p>TiDB 支持 Optimizer Hints 语法，它基于 MySQL 5.7 中介绍的类似 comment 的语法，例如 <code>/*+ HINT_NAME(t1, t2) */</code>。当 TiDB 优化器选择的不是最优查询计划时，建议使用 Optimizer Hints。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>MySQL 命令行客户端在 5.7.7 版本之前默认清除了 Optimizer Hints。如果需要在这些早期版本的客户端中使用 <code>Hint</code> 语法，需要在启动客户端时加上 <code>--comments</code> 选项，例如 <code>mysql -h 127.0.0.1 -P 4000 -uroot --comments</code>。</p></div></div></div><h2 id="语法" style="position:relative"><a href="#%E8%AF%AD%E6%B3%95" aria-label="语法 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>语法</h2><p>Optimizer Hints 不区分大小写，通过 <code>/*+ ... */</code> 注释的形式跟在 <code>SELECT</code>、<code>UPDATE</code> 或 <code>DELETE</code> 关键字的后面。<code>INSERT</code> 关键字后不支持 Optimizer Hints。</p><p>多个不同的 Hint 之间需用逗号隔开，例如：</p><pre><code class="hljs language-sql"><style data-emotion="css 1qhimia">.css-1qhimia{margin-right:3rem;overflow:auto;}</style><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ USE_INDEX(t1, idx1), HASH_AGG(), HASH_JOIN(t1) */</span> <span class="hljs-built_in">count</span>(<span class="hljs-operator">*</span>) <span class="hljs-keyword">FROM</span> t t1, t t2 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-operator">=</span> t2.b; </div><style data-emotion="css ux9q70">.css-ux9q70{text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:2.4rem;background:transparent;border:unset;}.css-ux9q70:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-ux9q70:hover{background-color:transparent;}}.css-ux9q70.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><style data-emotion="css 1rmx1rm">.css-1rmx1rm{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:2.4rem;background:transparent;border:unset;}.css-1rmx1rm::-moz-focus-inner{border-style:none;}.css-1rmx1rm.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-1rmx1rm{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-1rmx1rm:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-1rmx1rm:hover{background-color:transparent;}}.css-1rmx1rm.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><style data-emotion="css 1e2dcm1">.css-1e2dcm1{z-index:1500;pointer-events:none;}</style><style data-emotion="css okvapm">.css-okvapm{z-index:1500;pointer-events:none;}</style><style data-emotion="css rnn29l">.css-rnn29l{text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:0.625rem;background:transparent;border:unset;}.css-rnn29l:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-rnn29l:hover{background-color:transparent;}}.css-rnn29l.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><style data-emotion="css fxo539">.css-fxo539{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:0.625rem;background:transparent;border:unset;}.css-fxo539::-moz-focus-inner{border-style:none;}.css-fxo539.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-fxo539{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-fxo539:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-fxo539:hover{background-color:transparent;}}.css-fxo539.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>可以通过 <a href="/zh/tidb/v5.3/sql-statement-explain"><code>Explain</code></a>/<a href="/zh/tidb/v5.3/sql-statement-explain-analyze"><code>Explain Analyze</code></a> 语句的输出，来查看 Optimizer Hints 对查询执行计划的影响。</p><p>如果 Optimizer Hints 包含语法错误或不完整，查询语句不会报错，而是按照没有 Optimizer Hints 的情况执行。如果 Hint 不适用于当前语句，TiDB 会返回 Warning，用户可以在查询结束后通过 <code>Show Warnings</code> 命令查看具体信息。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>如果注释不是跟在指定的关键字后，会被当作是普通的 MySQL comment，注释不会生效，且不会上报 warning。</p></div></div></div><p>TiDB 目前支持的 Optimizer Hints 根据生效范围的不同可以划分为两类：第一类是在查询块范围生效的 Hint，例如 <a href="#hash_agg"><code>/*+ HASH_AGG() */</code></a>；第二类是在整个查询范围生效的 Hint，例如 <a href="#memory_quotan"><code>/*+ MEMORY_QUOTA(1024 MB)*/</code></a>。</p><p>每条语句中每一个查询和子查询都对应着一个不同的查询块，每个查询块有自己对应的名字。以下面这条语句为例：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> (<span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t) t1, (<span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t) t2; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>该查询语句有 3 个查询块，最外面一层 <code>SELECT</code> 所在的查询块的名字为 <code>sel_1</code>，两个 <code>SELECT</code> 子查询的名字依次为 <code>sel_2</code> 和 <code>sel_3</code>。其中数字序号根据 <code>SELECT</code> 出现的位置从左到右计数。如果分别用 <code>DELETE</code> 和 <code>UPDATE</code> 查询替代第一个 <code>SELECT</code> 查询，则对应的查询块名字分别为 <code>del_1</code> 和 <code>upd_1</code>。</p><h2 id="查询块范围生效的-hint" style="position:relative"><a href="#%E6%9F%A5%E8%AF%A2%E5%9D%97%E8%8C%83%E5%9B%B4%E7%94%9F%E6%95%88%E7%9A%84-hint" aria-label="查询块范围生效的 hint permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>查询块范围生效的 Hint</h2><p>这类 Hint 可以跟在查询语句中<strong>任意</strong> <code>SELECT</code>、<code>UPDATE</code> 或 <code>DELETE</code> 关键字的后面。通过在 Hint 中使用查询块名字可以控制 Hint 的生效范围，以及准确标识查询中的每一个表（有可能表的名字或者别名相同），方便明确 Hint 的参数指向。若不显式地在 Hint 中指定查询块，Hint 默认作用于当前查询块。以如下查询为例：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ HASH_JOIN(@sel_1 t1@sel_1, t3) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> (<span class="hljs-keyword">SELECT</span> t1.a, t1.b <span class="hljs-keyword">FROM</span> t t1, t t2 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-operator">=</span> t2.a) t1, t t3 <span class="hljs-keyword">WHERE</span> t1.b <span class="hljs-operator">=</span> t3.b; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>该 Hint 在 <code>sel_1</code> 这个查询块中生效，参数分别为 <code>sel_1</code> 中的 <code>t1</code> 表（<code>sel_2</code> 中也有一个 <code>t1</code> 表）和 <code>t3</code> 表。</p><p>如上例所述，在 Hint 中使用查询块名字的方式有两种：第一种是作为 Hint 的第一个参数，与其他参数用空格隔开。除 <code>QB_NAME</code> 外，本节所列的所有 Hint 除自身明确列出的参数外都有一个隐藏的可选参数 <code>@QB_NAME</code>，通过使用这个参数可以指定该 Hint 的生效范围；第二种在 Hint 中使用查询块名字的方式是在参数中的某一个表名后面加 <code>@QB_NAME</code>，用以明确指出该参数是哪个查询块中的表。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>Hint 声明的位置必须在指定生效的查询块之中或之前，不能是在之后的查询块中，否则无法生效。</p></div></div></div><h3 id="qb_name" style="position:relative"><a href="#qb_name" aria-label="qb_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>QB_NAME</h3><p>当查询语句是包含多层嵌套子查询的复杂语句时，识别某个查询块的序号和名字很可能会出错，Hint <code>QB_NAME</code> 可以方便我们使用查询块。<code>QB_NAME</code> 是 Query Block Name 的缩写，用于为某个查询块指定新的名字，同时查询块原本默认的名字依然有效。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ QB_NAME(QB1) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> (<span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t) t1, (<span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t) t2; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>这条 Hint 将最外层 <code>SELECT</code> 查询块的命名为 <code>QB1</code>，此时 <code>QB1</code> 和默认名称 <code>sel_1</code> 对于这个查询块来说都是有效的。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>上述例子中，如果指定的 <code>QB_NAME</code> 为 <code>sel_2</code>，并且不给原本 <code>sel_2</code> 对应的第二个查询块指定新的 <code>QB_NAME</code>，则第二个查询块的默认名字 <code>sel_2</code> 会失效。</p></div></div></div><h3 id="merge_joint1_name--tl_name-" style="position:relative"><a href="#merge_joint1_name--tl_name-" aria-label="merge_joint1_name tl_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>MERGE_JOIN(t1_name [, tl_name ...])</h3><p><code>MERGE_JOIN(t1_name [, tl_name ...])</code> 提示优化器对指定表使用 Sort Merge Join 算法。这个算法通常会占用更少的内存，但执行时间会更久。当数据量太大，或系统内存不足时，建议尝试使用。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ MERGE_JOIN(t1, t2) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t1，t2 <span class="hljs-keyword">WHERE</span> t1.id <span class="hljs-operator">=</span> t2.id; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p><code>MERGE_JOIN</code> 的别名是 <code>TIDB_SMJ</code>，在 3.0.x 及之前版本仅支持使用该别名；之后的版本同时支持使用这两种名称，但推荐使用 <code>MERGE_JOIN</code>。</p></div></div></div><h3 id="inl_joint1_name--tl_name-" style="position:relative"><a href="#inl_joint1_name--tl_name-" aria-label="inl_joint1_name tl_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>INL_JOIN(t1_name [, tl_name ...])</h3><p><code>INL_JOIN(t1_name [, tl_name ...])</code> 提示优化器对指定表使用 Index Nested Loop Join 算法。这个算法可能会在某些场景更快，消耗更少系统资源，有的场景会更慢，消耗更多系统资源。对于外表经过 WHERE 条件过滤后结果集较小（小于 1 万行）的场景，可以尝试使用。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ INL_JOIN(t1, t2) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t1，t2 <span class="hljs-keyword">WHERE</span> t1.id <span class="hljs-operator">=</span> t2.id; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p><code>INL_JOIN()</code> 中的参数是建立查询计划时内表的候选表，比如 <code>INL_JOIN(t1)</code> 只会考虑使用 t1 作为内表构建查询计划。表如果指定了别名，就只能使用表的别名作为 <code>INL_JOIN()</code> 的参数；如果没有指定别名，则用表的本名作为其参数。比如在 <code>SELECT /*+ INL_JOIN(t1) */ * FROM t t1, t t2 WHERE t1.a = t2.b;</code> 中，<code>INL_JOIN()</code> 的参数只能使用 t 的别名 t1 或 t2，不能用 t。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p><code>INL_JOIN</code> 的别名是 <code>TIDB_INLJ</code>，在 3.0.x 及之前版本仅支持使用该别名；之后的版本同时支持使用这两种名称，但推荐使用 <code>INL_JOIN</code>。</p></div></div></div><h3 id="inl_hash_join" style="position:relative"><a href="#inl_hash_join" aria-label="inl_hash_join permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>INL_HASH_JOIN</h3><p><code>INL_HASH_JOIN(t1_name [, tl_name])</code> 提示优化器使用 Index Nested Loop Hash Join 算法。该算法与 Index Nested Loop Join 使用条件完全一样，两者的区别是 <code>INL_JOIN</code> 会在连接的内表上建哈希表，而 <code>INL_HASH_JOIN</code> 会在连接的外表上建哈希表，后者对于内存的使用是有固定上限的，而前者使用的内存使用取决于内表匹配到的行数。</p><h3 id="hash_joint1_name--tl_name-" style="position:relative"><a href="#hash_joint1_name--tl_name-" aria-label="hash_joint1_name tl_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>HASH_JOIN(t1_name [, tl_name ...])</h3><p><code>HASH_JOIN(t1_name [, tl_name ...])</code> 提示优化器对指定表使用 Hash Join 算法。这个算法多线程并发执行，执行速度较快，但会消耗较多内存。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ HASH_JOIN(t1, t2) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t1，t2 <span class="hljs-keyword">WHERE</span> t1.id <span class="hljs-operator">=</span> t2.id; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p><code>HASH_JOIN</code> 的别名是 <code>TIDB_HJ</code>，在 3.0.x 及之前版本仅支持使用该别名；之后的版本同时支持使用这两种名称，推荐使用 <code>HASH_JOIN</code>。</p></div></div></div><h3 id="hash_agg" style="position:relative"><a href="#hash_agg" aria-label="hash_agg permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>HASH_AGG()</h3><p><code>HASH_AGG()</code> 提示优化器对指定查询块中所有聚合函数使用 Hash Aggregation 算法。这个算法多线程并发执行，执行速度较快，但会消耗较多内存。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ HASH_AGG() */</span> <span class="hljs-built_in">count</span>(<span class="hljs-operator">*</span>) <span class="hljs-keyword">FROM</span> t1，t2 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-operator">&gt;</span> <span class="hljs-number">10</span> <span class="hljs-keyword">GROUP</span> <span class="hljs-keyword">BY</span> t1.id; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="stream_agg" style="position:relative"><a href="#stream_agg" aria-label="stream_agg permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>STREAM_AGG()</h3><p><code>STREAM_AGG()</code> 提示优化器对指定查询块中所有聚合函数使用 Stream Aggregation 算法。这个算法通常会占用更少的内存，但执行时间会更久。数据量太大，或系统内存不足时，建议尝试使用。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ STREAM_AGG() */</span> <span class="hljs-built_in">count</span>(<span class="hljs-operator">*</span>) <span class="hljs-keyword">FROM</span> t1，t2 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-operator">&gt;</span> <span class="hljs-number">10</span> <span class="hljs-keyword">GROUP</span> <span class="hljs-keyword">BY</span> t1.id; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="use_indext1_name-idx1_name--idx2_name-" style="position:relative"><a href="#use_indext1_name-idx1_name--idx2_name-" aria-label="use_indext1_name idx1_name idx2_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>USE_INDEX(t1_name, idx1_name [, idx2_name ...])</h3><p><code>USE_INDEX(t1_name, idx1_name [, idx2_name ...])</code> 提示优化器对指定表仅使用给出的索引。</p><p>下面例子的效果等价于 <code>SELECT * FROM t t1 use index(idx1, idx2);</code>：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ USE_INDEX(t1, idx1, idx2) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t1; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>当该 Hint 中只指定表名，不指定索引名时，表示不考虑使用任何索引，而是选择全表扫。</p></div></div></div><h3 id="ignore_indext1_name-idx1_name--idx2_name-" style="position:relative"><a href="#ignore_indext1_name-idx1_name--idx2_name-" aria-label="ignore_indext1_name idx1_name idx2_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>IGNORE_INDEX(t1_name, idx1_name [, idx2_name ...])</h3><p><code>IGNORE_INDEX(t1_name, idx1_name [, idx2_name ...])</code> 提示优化器对指定表忽略给出的索引。</p><p>下面例子的效果等价于 <code>SELECT * FROM t t1 ignore index(idx1, idx2);</code>：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ IGNORE_INDEX(t1, idx1, idx2) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t t1; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="agg_to_cop" style="position:relative"><a href="#agg_to_cop" aria-label="agg_to_cop permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>AGG_TO_COP()</h3><p><code>AGG_TO_COP()</code> 提示优化器将指定查询块中的聚合函数下推到 coprocessor。如果优化器没有下推某些适合下推的聚合函数，建议尝试使用。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ AGG_TO_COP() */</span> <span class="hljs-built_in">sum</span>(t1.a) <span class="hljs-keyword">FROM</span> t t1; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="limit_to_cop" style="position:relative"><a href="#limit_to_cop" aria-label="limit_to_cop permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>LIMIT_TO_COP()</h3><p><code>LIMIT_TO_COP()</code> 提示优化器将指定查询块中的 <code>Limit</code> 和 <code>TopN</code> 算子下推到 coprocessor。优化器没有下推 <code>Limit</code> 或者 <code>TopN</code> 算子时建议尝试使用该提示。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ LIMIT_TO_COP() */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t <span class="hljs-keyword">WHERE</span> a <span class="hljs-operator">=</span> <span class="hljs-number">1</span> <span class="hljs-keyword">AND</span> b <span class="hljs-operator">&gt;</span> <span class="hljs-number">10</span> <span class="hljs-keyword">ORDER</span> <span class="hljs-keyword">BY</span> c LIMIT <span class="hljs-number">1</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="read_from_storagetiflasht1_name--tl_name--tikvt2_name--tl_name-" style="position:relative"><a href="#read_from_storagetiflasht1_name--tl_name--tikvt2_name--tl_name-" aria-label="read_from_storagetiflasht1_name tl_name tikvt2_name tl_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>READ_FROM_STORAGE(TIFLASH[t1_name [, tl_name ...]], TIKV[t2_name [, tl_name ...]])</h3><p><code>READ_FROM_STORAGE(TIFLASH[t1_name [, tl_name ...]], TIKV[t2_name [, tl_name ...]])</code> 提示优化器从指定的存储引擎来读取指定的表，目前支持的存储引擎参数有 <code>TIKV</code> 和 <code>TIFLASH</code>。如果为表指定了别名，就只能使用表的别名作为 <code>READ_FROM_STORAGE()</code> 的参数；如果没有指定别名，则用表的本名作为其参数。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ READ_FROM_STORAGE(TIFLASH[t1], TIKV[t2]) */</span> t1.a <span class="hljs-keyword">FROM</span> t t1, t t2 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-operator">=</span> t2.a; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>如果需要提示优化器使用的表不在同一个数据库内，需要显式指定数据库名。例如 <code>SELECT /*+ READ_FROM_STORAGE(TIFLASH[test1.t1,test2.t2]) */ t1.a FROM test1.t t1, test2.t t2 WHERE t1.a = t2.a;</code>。</p></div></div></div><h3 id="use_index_merget1_name-idx1_name--idx2_name-" style="position:relative"><a href="#use_index_merget1_name-idx1_name--idx2_name-" aria-label="use_index_merget1_name idx1_name idx2_name permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>USE_INDEX_MERGE(t1_name, idx1_name [, idx2_name ...])</h3><p><code>USE_INDEX_MERGE(t1_name, idx1_name [, idx2_name ...])</code> 提示优化器通过 index merge 的方式来访问指定的表，其中索引列表为可选参数。若显式地指出索引列表，会尝试在索引列表中选取索引来构建 index merge。若不给出索引列表，会尝试在所有可用的索引中选取索引来构建 index merge。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ USE_INDEX_MERGE(t1, idx_a, idx_b, idx_c) */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t1 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-operator">&gt;</span> <span class="hljs-number">10</span> <span class="hljs-keyword">OR</span> t1.b <span class="hljs-operator">&gt;</span> <span class="hljs-number">10</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>当对同一张表有多个 <code>USE_INDEX_MERGE</code> Hint 时，优化器会从这些 Hint 指定的索引列表的并集中尝试选取索引。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p><code>USE_INDEX_MERGE</code> 的参数是索引名，而不是列名。对于主键索引，索引名为 <code>primary</code>。</p></div></div></div><p>目前该 Hint 生效的条件较为苛刻，包括：</p><ul><li>如果查询有除了全表扫以外的单索引扫描方式可以选择，优化器不会选择 index merge；</li><li>如果查询在显式事务里，且该条查询之前的语句已经涉及写入，优化器不会选择 index merge；</li></ul><h2 id="查询范围生效的-hint" style="position:relative"><a href="#%E6%9F%A5%E8%AF%A2%E8%8C%83%E5%9B%B4%E7%94%9F%E6%95%88%E7%9A%84-hint" aria-label="查询范围生效的 hint permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>查询范围生效的 Hint</h2><p>这类 Hint 只能跟在语句中<strong>第一个</strong> <code>SELECT</code>、<code>UPDATE</code> 或 <code>DELETE</code> 关键字的后面，等同于在当前这条查询运行时对指定的系统变量进行修改，其优先级高于现有系统变量的值。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>这类 Hint 虽然也有隐藏的可选变量 <code>@QB_NAME</code>，但就算指定了该值，Hint 还是会在整个查询范围生效。</p></div></div></div><h3 id="no_index_merge" style="position:relative"><a href="#no_index_merge" aria-label="no_index_merge permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>NO_INDEX_MERGE()</h3><p><code>NO_INDEX_MERGE()</code> 会关闭优化器的 index merge 功能。</p><p>下面的例子不会使用 index merge：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ NO_INDEX_MERGE() */</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> t <span class="hljs-keyword">WHERE</span> t.a <span class="hljs-operator">&gt;</span> <span class="hljs-number">0</span> <span class="hljs-keyword">or</span> t.b <span class="hljs-operator">&gt;</span> <span class="hljs-number">0</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>除了 Hint 外，系统变量 <code>tidb_enable_index_merge</code> 也能决定是否开启该功能。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p><code>NO_INDEX_MERGE</code> 优先级高于 <code>USE_INDEX_MERGE</code>，当这两类 Hint 同时存在时，<code>USE_INDEX_MERGE</code> 不会生效。</p></div></div></div><h3 id="use_tojaboolean_value" style="position:relative"><a href="#use_tojaboolean_value" aria-label="use_tojaboolean_value permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>USE_TOJA(boolean_value)</h3><p>参数 <code>boolean_value</code> 可以是 <code>TRUE</code> 或者 <code>FALSE</code>。<code>USE_TOJA(TRUE)</code> 会开启优化器尝试将 in (subquery) 条件转换为 join 和 aggregation 的功能。相对地，<code>USE_TOJA(FALSE)</code> 会关闭该功能。</p><p>下面的例子会将 <code>in (SELECT t2.a FROM t2) subq</code> 转换为等价的 join 和 aggregation：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-comment">/*+ USE_TOJA(TRUE) */</span> t1.a, t1.b <span class="hljs-keyword">FROM</span> t1 <span class="hljs-keyword">WHERE</span> t1.a <span class="hljs-keyword">in</span> (<span class="hljs-keyword">SELECT</span> t2.a <span class="hljs-keyword">FROM</span> t2) subq;