(window.webpackJsonp=window.webpackJsonp||[]).push([[896],{1465:function(t,_,v){"use strict";v.r(_);var a=v(71),r=Object(a.a)({},(function(){var t=this,_=t.$createElement,v=t._self._c||_;return v("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[v("h1",{attrs:{id:"spark-iotdb-连接器"}},[v("a",{staticClass:"header-anchor",attrs:{href:"#spark-iotdb-连接器"}},[t._v("#")]),t._v(" Spark IOTDB 连接器")]),t._v(" "),v("h2",{attrs:{id:"设计目的"}},[v("a",{staticClass:"header-anchor",attrs:{href:"#设计目的"}},[t._v("#")]),t._v(" 设计目的")]),t._v(" "),v("ul",[v("li",[t._v("使用Spark SQL读取IOTDB的数据，以Spark DataFrame的形式返回给客户端")])]),t._v(" "),v("h2",{attrs:{id:"核心思想"}},[v("a",{staticClass:"header-anchor",attrs:{href:"#核心思想"}},[t._v("#")]),t._v(" 核心思想")]),t._v(" "),v("p",[t._v("由于IOTDB具有解析和执行SQL的能力，故该部分可以直接将SQL转发给IOTDB进程执行，将数据拿到后转换为RDD即可")]),t._v(" "),v("h2",{attrs:{id:"执行流程"}},[v("a",{staticClass:"header-anchor",attrs:{href:"#执行流程"}},[t._v("#")]),t._v(" 执行流程")]),t._v(" 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"),v("p",[t._v("由于Spark懒加载机制，用户遍历RDD时才具体调用RDD的迭代，也就是IOTDB的fetch Result")]),t._v(" "),v("ul",[v("li",[t._v("src/main/scala/org/apache/iotdb/spark/db/IoTDBRDD.scala中的getNext方法")])]),t._v(" "),v("h2",{attrs:{id:"宽窄表结构转换"}},[v("a",{staticClass:"header-anchor",attrs:{href:"#宽窄表结构转换"}},[t._v("#")]),t._v(" 宽窄表结构转换")]),t._v(" "),v("p",[t._v("宽表结构：IOTDB原生路径格式")]),t._v(" "),v("table",[v("thead",[v("tr",[v("th",[t._v("time")]),t._v(" "),v("th",[t._v("root.ln.wf02.wt02.temperature")]),t._v(" "),v("th",[t._v("root.ln.wf02.wt02.status")]),t._v(" "),v("th",[t._v("root.ln.wf02.wt02.hardware")]),t._v(" "),v("th",[t._v("root.ln.wf01.wt01.temperature")]),t._v(" "),v("th",[t._v("root.ln.wf01.wt01.status")]),t._v(" "),v("th",[t._v("root.ln.wf01.wt01.hardware")])])]),t._v(" "),v("tbody",[v("tr",[v("td",[t._v("1")]),t._v(" "),v("td",[t._v("null")]),t._v(" "),v("td",[t._v("true")]),t._v(" "),v("td",[t._v("null")]),t._v(" "),v("td",[t._v("2.2")]),t._v(" "),v("td",[t._v("true")]),t._v(" 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