(window.webpackJsonp=window.webpackJsonp||[]).push([[358],{922:function(e,s,t){"use strict";t.r(s);var r=t(68),a=Object(r.a)({},(function(){var e=this,s=e.$createElement,t=e._self._c||s;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("h1",{attrs:{id:"性能追踪工具"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#性能追踪工具"}},[e._v("#")]),e._v(" 性能追踪工具")]),e._v(" "),t("p",[e._v("IoTDB 支持使用 "),t("code",[e._v("TRACING")]),e._v(" 语句来启用/禁用对查询语句的性能追踪，默认处于禁用状态。用户可以使用性能追踪工具来分析某些查询中存在的潜在性能问题。性能分析的日志文件默认存储在 "),t("code",[e._v("./data/tracing")]),e._v(" 目录下。")]),e._v(" "),t("p",[e._v("启用 Tracing：")]),e._v(" "),t("p",[t("code",[e._v("IoTDB> TRACING ON")])]),e._v(" "),t("p",[e._v("禁用 Tracing：")]),e._v(" "),t("p",[t("code",[e._v("IoTDB> TRACING OFF")])]),e._v(" "),t("p",[e._v("由于一个 IoTDB 查询时间主要取决于查询的时间序列数、涉及访问的 Tsfile 文件数、需要扫描的 chunk 总数以及平均每个 chunk 的大小（指该 chunk 中包含的数据点的个数）。因此，目前性能分析包括的内容如下：")]),e._v(" "),t("ul",[t("li",[e._v("Start time")]),e._v(" "),t("li",[e._v("Query statement")]),e._v(" "),t("li",[e._v("Number of series paths")]),e._v(" "),t("li",[e._v("Number of sequence files")]),e._v(" "),t("li",[e._v("Statistics of each sequence file")]),e._v(" "),t("li",[e._v("Number of unSequence files")]),e._v(" "),t("li",[e._v("Statistics of each unSequence file")]),e._v(" "),t("li",[e._v("Number of chunks")]),e._v(" "),t("li",[e._v("Average size of chunks")]),e._v(" "),t("li",[e._v("Total cost time")])]),e._v(" "),t("h2",{attrs:{id:"example"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#example"}},[e._v("#")]),e._v(" Example")]),e._v(" "),t("p",[e._v("例如执行 "),t("code",[e._v("select * from root")]),e._v("，则 tracing 日志文件的内容会包括以下内容：")]),e._v(" "),t("div",{staticClass:"language- line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("Query Id: 2 - Start time: 2020-06-28 10:53:54.727\nQuery Id: 2 - Query Statement: select * from root\nQuery Id: 2 - Number of series paths: 3\nQuery Id: 2 - Number of sequence files: 1\nQuery Id: 2 - SeqFile_1603336100446-1-0.tsfile root.sg.d1[1, 10000]\nQuery Id: 2 - Number of unsequence files: 1\nQuery Id: 2 - UnSeqFile_1603354798303-2-0.tsfile root.sg.d1[9, 1000]\nQuery Id: 2 - Number of chunks: 3\nQuery Id: 2 - Average size of chunks: 4113\nQuery Id: 2 - Total cost time: 11ms\n")])]),e._v(" "),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[e._v("1")]),t("br"),t("span",{staticClass:"line-number"},[e._v("2")]),t("br"),t("span",{staticClass:"line-number"},[e._v("3")]),t("br"),t("span",{staticClass:"line-number"},[e._v("4")]),t("br"),t("span",{staticClass:"line-number"},[e._v("5")]),t("br"),t("span",{staticClass:"line-number"},[e._v("6")]),t("br"),t("span",{staticClass:"line-number"},[e._v("7")]),t("br"),t("span",{staticClass:"line-number"},[e._v("8")]),t("br"),t("span",{staticClass:"line-number"},[e._v("9")]),t("br"),t("span",{staticClass:"line-number"},[e._v("10")]),t("br")])]),t("p",[e._v("为了避免多个查询同时执行导致输出信息乱序，在每条输出信息前均增加了该次查询的 Query Id，用户可以使用 "),t("code",[e._v('grep "Query Id: 2" tracing.txt')]),e._v(" 来提取某次查询的所有追踪信息。")])])}),[],!1,null,null,null);s.default=a.exports}}]);