blob: 2364813240611b2f8132e3e5737c707d3a38ecc8 [file] [log] [blame]
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title> </title>
<meta name="generator" content="VuePress 1.8.2">
<link rel="icon" href="/favicon.ico">
<meta name="description" content=" ">
<meta name="Description" content="Apache IoTDB: Time Series Database for IoT">
<meta name="Keywords" content="TSDB, time series, time series database, IoTDB, IoT database, IoT data management,时序数据库, 时间序列管理, IoTDB, 物联网数据库, 实时数据库, 物联网数据管理, 物联网数据">
<meta name="baidu-site-verification" content="wfKETzB3OT">
<meta name="google-site-verification" content="mZWAoRY0yj_HAr-s47zHCGHzx5Ju-RVm5wDbPnwQYFo">
<link rel="preload" href="/assets/css/0.styles.ccadf850.css" as="style"><link rel="preload" href="/assets/js/app.0ce1fe55.js" as="script"><link rel="preload" href="/assets/js/3.5626571b.js" as="script"><link rel="preload" href="/assets/js/297.9c1e3937.js" as="script"><link rel="prefetch" href="/assets/js/10.77e7d27b.js"><link rel="prefetch" href="/assets/js/100.ed95c785.js"><link rel="prefetch" href="/assets/js/101.a72c7dae.js"><link rel="prefetch" href="/assets/js/102.dfb385f3.js"><link rel="prefetch" href="/assets/js/103.3cb9e1be.js"><link rel="prefetch" href="/assets/js/104.522d3ff0.js"><link rel="prefetch" href="/assets/js/105.5ab143cb.js"><link rel="prefetch" href="/assets/js/106.7410be55.js"><link rel="prefetch" href="/assets/js/107.4b6fc970.js"><link rel="prefetch" href="/assets/js/108.f245629a.js"><link rel="prefetch" href="/assets/js/109.ae58680f.js"><link rel="prefetch" href="/assets/js/11.a080efae.js"><link rel="prefetch" href="/assets/js/110.3bee101b.js"><link rel="prefetch" href="/assets/js/111.03fb1ee4.js"><link rel="prefetch" href="/assets/js/112.0171a2e0.js"><link rel="prefetch" href="/assets/js/113.46505989.js"><link rel="prefetch" href="/assets/js/114.2fa2f181.js"><link rel="prefetch" href="/assets/js/115.fbfba1eb.js"><link rel="prefetch" href="/assets/js/116.afbd129c.js"><link rel="prefetch" href="/assets/js/117.a9624855.js"><link rel="prefetch" href="/assets/js/118.01244d82.js"><link rel="prefetch" href="/assets/js/119.36fd80be.js"><link rel="prefetch" href="/assets/js/12.30292c04.js"><link rel="prefetch" href="/assets/js/120.b489d365.js"><link rel="prefetch" href="/assets/js/121.3bdd405d.js"><link rel="prefetch" href="/assets/js/122.e8ff4d57.js"><link rel="prefetch" href="/assets/js/123.df016054.js"><link rel="prefetch" href="/assets/js/124.824251ee.js"><link rel="prefetch" href="/assets/js/125.68a30edd.js"><link rel="prefetch" href="/assets/js/126.6b0abad7.js"><link rel="prefetch" href="/assets/js/127.4cb256b7.js"><link rel="prefetch" href="/assets/js/128.285188c2.js"><link rel="prefetch" href="/assets/js/129.d5bb81f9.js"><link rel="prefetch" href="/assets/js/13.88849b9d.js"><link rel="prefetch" href="/assets/js/130.866c33c2.js"><link rel="prefetch" href="/assets/js/131.96da42f5.js"><link rel="prefetch" href="/assets/js/132.1ceb9f98.js"><link rel="prefetch" href="/assets/js/133.4c74e215.js"><link rel="prefetch" href="/assets/js/134.70817ed0.js"><link rel="prefetch" href="/assets/js/135.b893c04a.js"><link rel="prefetch" href="/assets/js/136.8dacb951.js"><link rel="prefetch" href="/assets/js/137.88ca76ee.js"><link rel="prefetch" href="/assets/js/138.58faf437.js"><link rel="prefetch" href="/assets/js/139.5ffbc26e.js"><link rel="prefetch" href="/assets/js/14.e275d1c0.js"><link rel="prefetch" href="/assets/js/140.06fd42b3.js"><link rel="prefetch" href="/assets/js/141.d61183b2.js"><link rel="prefetch" href="/assets/js/142.80570522.js"><link rel="prefetch" href="/assets/js/143.c382b0b8.js"><link rel="prefetch" href="/assets/js/144.93007f46.js"><link rel="prefetch" href="/assets/js/145.1c62a4d0.js"><link rel="prefetch" href="/assets/js/146.e48d5d3f.js"><link rel="prefetch" href="/assets/js/147.fdd69e02.js"><link rel="prefetch" href="/assets/js/148.a56545f4.js"><link rel="prefetch" href="/assets/js/149.47acfbaf.js"><link rel="prefetch" href="/assets/js/15.0953eb10.js"><link rel="prefetch" href="/assets/js/150.973f7a4f.js"><link rel="prefetch" href="/assets/js/151.52b9bd4e.js"><link rel="prefetch" href="/assets/js/152.2dba0b31.js"><link rel="prefetch" href="/assets/js/153.16354cc9.js"><link rel="prefetch" href="/assets/js/154.21b3e81c.js"><link rel="prefetch" href="/assets/js/155.d4c854aa.js"><link rel="prefetch" href="/assets/js/156.35418505.js"><link rel="prefetch" href="/assets/js/157.de989c5f.js"><link rel="prefetch" href="/assets/js/158.2d4ad862.js"><link rel="prefetch" href="/assets/js/159.73d92fce.js"><link rel="prefetch" href="/assets/js/16.be3a02b8.js"><link rel="prefetch" href="/assets/js/160.86b5996e.js"><link rel="prefetch" href="/assets/js/161.1115b4c2.js"><link rel="prefetch" href="/assets/js/162.8e8f0b7a.js"><link rel="prefetch" href="/assets/js/163.5b7b3c3b.js"><link rel="prefetch" href="/assets/js/164.62e12d30.js"><link rel="prefetch" href="/assets/js/165.29bdf72b.js"><link rel="prefetch" href="/assets/js/166.6337999d.js"><link rel="prefetch" href="/assets/js/167.24ec612c.js"><link rel="prefetch" href="/assets/js/168.e3979906.js"><link rel="prefetch" href="/assets/js/169.f8620ad1.js"><link rel="prefetch" href="/assets/js/17.9b09b22d.js"><link rel="prefetch" href="/assets/js/170.963a59df.js"><link rel="prefetch" href="/assets/js/171.c66629ae.js"><link rel="prefetch" href="/assets/js/172.f03ac5e4.js"><link rel="prefetch" href="/assets/js/173.290ef6a3.js"><link rel="prefetch" href="/assets/js/174.bb8dd7b0.js"><link rel="prefetch" href="/assets/js/175.1f574749.js"><link rel="prefetch" href="/assets/js/176.483d45ae.js"><link rel="prefetch" href="/assets/js/177.1f8917c5.js"><link rel="prefetch" href="/assets/js/178.ca5b82c4.js"><link rel="prefetch" href="/assets/js/179.23e1b953.js"><link rel="prefetch" href="/assets/js/18.122d5826.js"><link rel="prefetch" href="/assets/js/180.d6609806.js"><link rel="prefetch" href="/assets/js/181.7b6deef5.js"><link rel="prefetch" href="/assets/js/182.b157bcef.js"><link rel="prefetch" href="/assets/js/183.fc45ef1f.js"><link rel="prefetch" href="/assets/js/184.5e948b32.js"><link rel="prefetch" href="/assets/js/185.59a533a9.js"><link rel="prefetch" href="/assets/js/186.0f0c43ae.js"><link rel="prefetch" href="/assets/js/187.6ff8df1b.js"><link rel="prefetch" href="/assets/js/188.25b531d8.js"><link rel="prefetch" href="/assets/js/189.8a164280.js"><link rel="prefetch" href="/assets/js/19.9187dec1.js"><link rel="prefetch" href="/assets/js/190.da803251.js"><link rel="prefetch" href="/assets/js/191.d41b5323.js"><link rel="prefetch" href="/assets/js/192.0bc2dfe6.js"><link rel="prefetch" href="/assets/js/193.cddd3be4.js"><link rel="prefetch" href="/assets/js/194.f7be5759.js"><link rel="prefetch" href="/assets/js/195.8a4d26c7.js"><link rel="prefetch" href="/assets/js/196.69252987.js"><link rel="prefetch" href="/assets/js/197.5ace5f08.js"><link rel="prefetch" href="/assets/js/198.a1dcce0c.js"><link rel="prefetch" href="/assets/js/199.793c8aa6.js"><link rel="prefetch" href="/assets/js/20.cf088c3b.js"><link rel="prefetch" href="/assets/js/200.ae99c7c2.js"><link rel="prefetch" href="/assets/js/201.48f48797.js"><link rel="prefetch" href="/assets/js/202.d7f7dd0b.js"><link rel="prefetch" href="/assets/js/203.f2d66570.js"><link rel="prefetch" href="/assets/js/204.898ab824.js"><link rel="prefetch" href="/assets/js/205.548b05ec.js"><link rel="prefetch" href="/assets/js/206.22914a2c.js"><link rel="prefetch" href="/assets/js/207.6a13e9ee.js"><link rel="prefetch" href="/assets/js/208.acb612aa.js"><link rel="prefetch" href="/assets/js/209.cdc82615.js"><link rel="prefetch" href="/assets/js/21.acbfa763.js"><link rel="prefetch" href="/assets/js/210.fe9edc74.js"><link rel="prefetch" href="/assets/js/211.15611bfc.js"><link rel="prefetch" href="/assets/js/212.104e35e7.js"><link rel="prefetch" href="/assets/js/213.09979614.js"><link rel="prefetch" href="/assets/js/214.766637ac.js"><link rel="prefetch" href="/assets/js/215.b3ec2479.js"><link rel="prefetch" href="/assets/js/216.6aa72a6d.js"><link rel="prefetch" href="/assets/js/217.bd6d9c4a.js"><link rel="prefetch" href="/assets/js/218.128ec60b.js"><link rel="prefetch" href="/assets/js/219.17f98efb.js"><link rel="prefetch" href="/assets/js/22.1e7200c8.js"><link rel="prefetch" href="/assets/js/220.6ecbd946.js"><link rel="prefetch" href="/assets/js/221.e8946ff5.js"><link rel="prefetch" href="/assets/js/222.a9c9ecd1.js"><link rel="prefetch" href="/assets/js/223.fb011059.js"><link rel="prefetch" href="/assets/js/224.cf6ca794.js"><link rel="prefetch" href="/assets/js/225.ee730a7f.js"><link rel="prefetch" href="/assets/js/226.c094a61b.js"><link rel="prefetch" href="/assets/js/227.0aded7a3.js"><link rel="prefetch" href="/assets/js/228.ac120f0d.js"><link rel="prefetch" href="/assets/js/229.812c8049.js"><link rel="prefetch" href="/assets/js/23.91ba0b88.js"><link rel="prefetch" href="/assets/js/230.501080a7.js"><link rel="prefetch" href="/assets/js/231.cf1146c1.js"><link rel="prefetch" href="/assets/js/232.4f6b6373.js"><link rel="prefetch" href="/assets/js/233.0e95edce.js"><link rel="prefetch" href="/assets/js/234.f84b642d.js"><link rel="prefetch" href="/assets/js/235.3805944b.js"><link rel="prefetch" href="/assets/js/236.b977dbf2.js"><link rel="prefetch" href="/assets/js/237.7630406d.js"><link rel="prefetch" href="/assets/js/238.694d8754.js"><link rel="prefetch" href="/assets/js/239.3fb83483.js"><link rel="prefetch" href="/assets/js/24.ae2f738e.js"><link rel="prefetch" href="/assets/js/240.9b363f24.js"><link rel="prefetch" href="/assets/js/241.a7a523e1.js"><link rel="prefetch" href="/assets/js/242.86e3c344.js"><link rel="prefetch" href="/assets/js/243.7598764a.js"><link rel="prefetch" href="/assets/js/244.3e90e4bc.js"><link rel="prefetch" href="/assets/js/245.a61d71ed.js"><link rel="prefetch" href="/assets/js/246.20d4e857.js"><link rel="prefetch" href="/assets/js/247.78cf01d5.js"><link rel="prefetch" href="/assets/js/248.4741dcd9.js"><link rel="prefetch" href="/assets/js/249.d15adfc9.js"><link rel="prefetch" href="/assets/js/25.a807a864.js"><link rel="prefetch" href="/assets/js/250.f07ef0ee.js"><link rel="prefetch" href="/assets/js/251.9a48a958.js"><link rel="prefetch" href="/assets/js/252.811a7e8c.js"><link rel="prefetch" href="/assets/js/253.b0c50955.js"><link rel="prefetch" href="/assets/js/254.f315a0f9.js"><link rel="prefetch" href="/assets/js/255.f56babf3.js"><link rel="prefetch" href="/assets/js/256.abcbc078.js"><link rel="prefetch" href="/assets/js/257.ea907563.js"><link rel="prefetch" href="/assets/js/258.9431d26e.js"><link rel="prefetch" href="/assets/js/259.c7d62dfa.js"><link rel="prefetch" href="/assets/js/26.2121ac8d.js"><link rel="prefetch" href="/assets/js/260.e9f192d6.js"><link rel="prefetch" href="/assets/js/261.3c8b8c14.js"><link rel="prefetch" href="/assets/js/262.8004896a.js"><link rel="prefetch" href="/assets/js/263.eee29284.js"><link rel="prefetch" href="/assets/js/264.cb79ef91.js"><link rel="prefetch" href="/assets/js/265.9a2f2a85.js"><link rel="prefetch" href="/assets/js/266.ca225af9.js"><link rel="prefetch" href="/assets/js/267.beea5d0a.js"><link rel="prefetch" href="/assets/js/268.f1583bf9.js"><link rel="prefetch" href="/assets/js/269.6e097d45.js"><link rel="prefetch" href="/assets/js/27.353617df.js"><link rel="prefetch" href="/assets/js/270.92f71014.js"><link rel="prefetch" href="/assets/js/271.4e2ab885.js"><link rel="prefetch" href="/assets/js/272.3f6ce0f3.js"><link rel="prefetch" href="/assets/js/273.c1b6e198.js"><link rel="prefetch" href="/assets/js/274.9b163077.js"><link rel="prefetch" href="/assets/js/275.785fd825.js"><link rel="prefetch" href="/assets/js/276.4658b553.js"><link rel="prefetch" href="/assets/js/277.07c63ac9.js"><link rel="prefetch" href="/assets/js/278.8b7117be.js"><link rel="prefetch" href="/assets/js/279.2caa2bbe.js"><link rel="prefetch" href="/assets/js/28.0a801078.js"><link rel="prefetch" href="/assets/js/280.55ec4f01.js"><link rel="prefetch" href="/assets/js/281.abe12294.js"><link rel="prefetch" href="/assets/js/282.1eb0458c.js"><link rel="prefetch" href="/assets/js/283.c3249204.js"><link rel="prefetch" href="/assets/js/284.ac2bf191.js"><link rel="prefetch" href="/assets/js/285.bca6aa40.js"><link rel="prefetch" href="/assets/js/286.6cbe9274.js"><link rel="prefetch" href="/assets/js/287.ec6242a0.js"><link rel="prefetch" href="/assets/js/288.479655dd.js"><link rel="prefetch" href="/assets/js/289.659caaed.js"><link rel="prefetch" href="/assets/js/29.a31435b1.js"><link rel="prefetch" href="/assets/js/290.f024ff5f.js"><link rel="prefetch" href="/assets/js/291.6e1a6c9b.js"><link rel="prefetch" href="/assets/js/292.ace942a5.js"><link rel="prefetch" href="/assets/js/293.60efa2c4.js"><link rel="prefetch" href="/assets/js/294.db318cdf.js"><link rel="prefetch" href="/assets/js/295.7adfdd6a.js"><link rel="prefetch" href="/assets/js/296.084dabd5.js"><link rel="prefetch" href="/assets/js/298.91b1b31c.js"><link rel="prefetch" href="/assets/js/299.348f494c.js"><link rel="prefetch" href="/assets/js/30.2a011d46.js"><link rel="prefetch" href="/assets/js/300.ecae56e5.js"><link rel="prefetch" href="/assets/js/301.7986fcfa.js"><link rel="prefetch" href="/assets/js/302.fbea453a.js"><link rel="prefetch" href="/assets/js/303.90b0c08b.js"><link rel="prefetch" href="/assets/js/304.ae9e278b.js"><link rel="prefetch" href="/assets/js/305.ca97e9f9.js"><link rel="prefetch" href="/assets/js/306.bd049505.js"><link rel="prefetch" href="/assets/js/307.e3d537d7.js"><link rel="prefetch" href="/assets/js/308.3e23d630.js"><link rel="prefetch" href="/assets/js/309.d083bb39.js"><link rel="prefetch" href="/assets/js/31.9af92350.js"><link rel="prefetch" href="/assets/js/310.e410f107.js"><link rel="prefetch" href="/assets/js/311.da17b546.js"><link rel="prefetch" href="/assets/js/312.10873f86.js"><link rel="prefetch" href="/assets/js/313.fc0e389d.js"><link rel="prefetch" href="/assets/js/314.7f57565d.js"><link rel="prefetch" href="/assets/js/315.8130feb6.js"><link rel="prefetch" href="/assets/js/316.e688278e.js"><link rel="prefetch" href="/assets/js/317.0719853c.js"><link rel="prefetch" href="/assets/js/318.bee76827.js"><link rel="prefetch" href="/assets/js/319.3734e844.js"><link rel="prefetch" href="/assets/js/32.c5d0178e.js"><link rel="prefetch" href="/assets/js/320.0bdbffa7.js"><link rel="prefetch" href="/assets/js/321.a656f950.js"><link rel="prefetch" href="/assets/js/322.421250b3.js"><link rel="prefetch" href="/assets/js/323.2efb7b59.js"><link rel="prefetch" href="/assets/js/324.5e31b5b7.js"><link rel="prefetch" href="/assets/js/325.017d4ac6.js"><link rel="prefetch" href="/assets/js/326.2aad02c9.js"><link rel="prefetch" href="/assets/js/327.a2797c70.js"><link rel="prefetch" href="/assets/js/328.eab6f5e8.js"><link rel="prefetch" href="/assets/js/329.a8397efb.js"><link rel="prefetch" href="/assets/js/33.71e8ea0b.js"><link rel="prefetch" href="/assets/js/330.4d8e6aea.js"><link rel="prefetch" href="/assets/js/331.bc6db7fb.js"><link rel="prefetch" href="/assets/js/332.c7d955a8.js"><link rel="prefetch" href="/assets/js/333.2f5a4151.js"><link rel="prefetch" href="/assets/js/334.ff533799.js"><link rel="prefetch" href="/assets/js/335.a52d6bb0.js"><link rel="prefetch" href="/assets/js/336.dd48593b.js"><link rel="prefetch" href="/assets/js/337.91b7a655.js"><link rel="prefetch" href="/assets/js/338.e1fb9242.js"><link rel="prefetch" href="/assets/js/339.17770dae.js"><link rel="prefetch" href="/assets/js/34.85849ed4.js"><link rel="prefetch" href="/assets/js/340.4378eed8.js"><link rel="prefetch" href="/assets/js/341.195a8b13.js"><link rel="prefetch" href="/assets/js/342.8058dc21.js"><link rel="prefetch" href="/assets/js/343.b5963f08.js"><link rel="prefetch" href="/assets/js/344.b246b989.js"><link rel="prefetch" href="/assets/js/345.fc088fdc.js"><link rel="prefetch" href="/assets/js/346.b959a237.js"><link rel="prefetch" href="/assets/js/347.bcf05eb4.js"><link rel="prefetch" href="/assets/js/348.031e352c.js"><link rel="prefetch" href="/assets/js/349.b7348c86.js"><link rel="prefetch" href="/assets/js/35.5612ab6a.js"><link rel="prefetch" href="/assets/js/350.40896ba0.js"><link rel="prefetch" href="/assets/js/351.085e1aa5.js"><link rel="prefetch" href="/assets/js/352.5e157563.js"><link rel="prefetch" href="/assets/js/353.cfe4cf8b.js"><link rel="prefetch" href="/assets/js/354.2f911c8d.js"><link rel="prefetch" href="/assets/js/355.c6db4669.js"><link rel="prefetch" href="/assets/js/356.06b3fae5.js"><link rel="prefetch" href="/assets/js/357.eb9c2f7f.js"><link rel="prefetch" href="/assets/js/358.bb431ab1.js"><link rel="prefetch" href="/assets/js/359.91cac463.js"><link rel="prefetch" href="/assets/js/36.5a401e9f.js"><link rel="prefetch" href="/assets/js/360.eafce21a.js"><link rel="prefetch" href="/assets/js/361.38501bb2.js"><link rel="prefetch" href="/assets/js/362.7b397d7f.js"><link rel="prefetch" href="/assets/js/363.2e16cffe.js"><link rel="prefetch" href="/assets/js/364.d17737d3.js"><link rel="prefetch" href="/assets/js/365.19b72317.js"><link rel="prefetch" href="/assets/js/366.46fbd6f7.js"><link rel="prefetch" href="/assets/js/367.ce39afbb.js"><link rel="prefetch" href="/assets/js/368.e46272ab.js"><link rel="prefetch" href="/assets/js/369.b07caead.js"><link rel="prefetch" href="/assets/js/37.15871763.js"><link rel="prefetch" href="/assets/js/370.01c84a7d.js"><link rel="prefetch" href="/assets/js/371.c1d1c747.js"><link rel="prefetch" href="/assets/js/372.205e1d0f.js"><link rel="prefetch" href="/assets/js/373.aa42888a.js"><link rel="prefetch" href="/assets/js/374.7e10d4da.js"><link rel="prefetch" href="/assets/js/375.1c735a6d.js"><link rel="prefetch" href="/assets/js/376.32e78885.js"><link rel="prefetch" href="/assets/js/377.fcf2fadd.js"><link rel="prefetch" href="/assets/js/378.18f444fd.js"><link rel="prefetch" href="/assets/js/379.879738d8.js"><link rel="prefetch" href="/assets/js/38.b02b6af6.js"><link rel="prefetch" href="/assets/js/380.105520b2.js"><link rel="prefetch" href="/assets/js/381.df41b097.js"><link rel="prefetch" href="/assets/js/382.a1239949.js"><link rel="prefetch" href="/assets/js/383.22938fc1.js"><link rel="prefetch" href="/assets/js/384.4e79e5eb.js"><link rel="prefetch" href="/assets/js/385.e7aa33d8.js"><link rel="prefetch" href="/assets/js/386.b037901f.js"><link rel="prefetch" href="/assets/js/387.3b662ff8.js"><link rel="prefetch" href="/assets/js/388.a1ae1ede.js"><link rel="prefetch" href="/assets/js/389.fdbf3ddd.js"><link rel="prefetch" href="/assets/js/39.b5f4c79a.js"><link rel="prefetch" href="/assets/js/390.336a9553.js"><link rel="prefetch" href="/assets/js/391.22842119.js"><link rel="prefetch" href="/assets/js/392.577fed5c.js"><link rel="prefetch" href="/assets/js/393.cf98216d.js"><link rel="prefetch" href="/assets/js/394.a4ab2881.js"><link rel="prefetch" href="/assets/js/395.568f1de1.js"><link rel="prefetch" href="/assets/js/396.eabe4d04.js"><link rel="prefetch" href="/assets/js/397.14a239f0.js"><link rel="prefetch" href="/assets/js/398.ecadeab8.js"><link rel="prefetch" href="/assets/js/399.dea55ac6.js"><link rel="prefetch" href="/assets/js/4.a195f7b6.js"><link rel="prefetch" href="/assets/js/40.0f31bd56.js"><link rel="prefetch" href="/assets/js/400.3e52b52e.js"><link rel="prefetch" href="/assets/js/401.917f34b9.js"><link rel="prefetch" href="/assets/js/402.b9b6b243.js"><link rel="prefetch" href="/assets/js/403.d18ffde3.js"><link rel="prefetch" href="/assets/js/404.ee871365.js"><link rel="prefetch" href="/assets/js/405.57bc9408.js"><link rel="prefetch" href="/assets/js/406.7c793667.js"><link rel="prefetch" href="/assets/js/407.b6d62a2e.js"><link rel="prefetch" href="/assets/js/408.0873bd31.js"><link rel="prefetch" href="/assets/js/409.6cb23d39.js"><link rel="prefetch" href="/assets/js/41.f483212d.js"><link rel="prefetch" href="/assets/js/410.19de2693.js"><link rel="prefetch" href="/assets/js/411.21b2c909.js"><link rel="prefetch" href="/assets/js/412.98ab43f7.js"><link rel="prefetch" href="/assets/js/413.54a50c02.js"><link rel="prefetch" href="/assets/js/414.1f5da68b.js"><link rel="prefetch" href="/assets/js/415.a8a38d22.js"><link rel="prefetch" href="/assets/js/416.8512f96d.js"><link rel="prefetch" href="/assets/js/417.b82389ad.js"><link rel="prefetch" href="/assets/js/418.7f94375e.js"><link rel="prefetch" href="/assets/js/419.81e6d8e2.js"><link rel="prefetch" href="/assets/js/42.ffb032af.js"><link rel="prefetch" href="/assets/js/420.f9c6fd90.js"><link rel="prefetch" href="/assets/js/421.9f59b9c4.js"><link rel="prefetch" href="/assets/js/422.82169579.js"><link rel="prefetch" href="/assets/js/423.3edd713e.js"><link rel="prefetch" href="/assets/js/424.3a36d255.js"><link rel="prefetch" href="/assets/js/425.bf12e1f3.js"><link rel="prefetch" href="/assets/js/426.35170657.js"><link rel="prefetch" href="/assets/js/427.66eb3fe5.js"><link rel="prefetch" href="/assets/js/428.789479d6.js"><link rel="prefetch" href="/assets/js/429.8fd5e3a8.js"><link rel="prefetch" href="/assets/js/43.7406f914.js"><link rel="prefetch" href="/assets/js/430.02d54f8e.js"><link rel="prefetch" href="/assets/js/431.5b6ab928.js"><link rel="prefetch" href="/assets/js/432.6fcad8ff.js"><link rel="prefetch" href="/assets/js/433.44e82676.js"><link rel="prefetch" href="/assets/js/434.abe5ffe2.js"><link rel="prefetch" href="/assets/js/435.f7d1dc69.js"><link rel="prefetch" href="/assets/js/436.edaf4612.js"><link rel="prefetch" href="/assets/js/437.c4e29f95.js"><link rel="prefetch" href="/assets/js/438.db8053bc.js"><link rel="prefetch" href="/assets/js/439.b0661d24.js"><link rel="prefetch" href="/assets/js/44.3bea749e.js"><link rel="prefetch" href="/assets/js/440.eadeab90.js"><link rel="prefetch" href="/assets/js/441.2e885d78.js"><link rel="prefetch" href="/assets/js/442.9d8c820e.js"><link rel="prefetch" href="/assets/js/443.40d31ee9.js"><link rel="prefetch" href="/assets/js/444.4f0d0db9.js"><link rel="prefetch" href="/assets/js/445.5b5deffe.js"><link rel="prefetch" href="/assets/js/446.89603481.js"><link rel="prefetch" href="/assets/js/447.79221ab3.js"><link rel="prefetch" href="/assets/js/448.19cb412f.js"><link rel="prefetch" href="/assets/js/449.1f3f0541.js"><link rel="prefetch" href="/assets/js/45.244b7680.js"><link rel="prefetch" href="/assets/js/450.3eca4d3a.js"><link rel="prefetch" href="/assets/js/451.ae55be40.js"><link rel="prefetch" href="/assets/js/452.9cbb7afe.js"><link rel="prefetch" href="/assets/js/453.f3859daa.js"><link rel="prefetch" href="/assets/js/454.adeb5481.js"><link rel="prefetch" href="/assets/js/455.93f4a8e9.js"><link rel="prefetch" href="/assets/js/456.9f8ad05f.js"><link rel="prefetch" href="/assets/js/457.22496879.js"><link rel="prefetch" href="/assets/js/458.e9503d84.js"><link rel="prefetch" href="/assets/js/459.370e44e7.js"><link rel="prefetch" href="/assets/js/46.539f062d.js"><link rel="prefetch" href="/assets/js/460.1abdd421.js"><link rel="prefetch" href="/assets/js/461.3b85e094.js"><link rel="prefetch" href="/assets/js/462.882326da.js"><link rel="prefetch" href="/assets/js/463.822487eb.js"><link rel="prefetch" href="/assets/js/464.5aa364f7.js"><link rel="prefetch" href="/assets/js/465.7422742d.js"><link rel="prefetch" href="/assets/js/466.c07cb7a4.js"><link rel="prefetch" href="/assets/js/467.47ef006b.js"><link rel="prefetch" href="/assets/js/468.89ef96ad.js"><link rel="prefetch" href="/assets/js/469.bfffaee9.js"><link rel="prefetch" href="/assets/js/47.13872d6f.js"><link rel="prefetch" href="/assets/js/470.b3ff2f13.js"><link rel="prefetch" href="/assets/js/471.05120819.js"><link rel="prefetch" href="/assets/js/472.3892f52c.js"><link rel="prefetch" href="/assets/js/473.aa6bd5ba.js"><link rel="prefetch" href="/assets/js/474.f1ac334b.js"><link rel="prefetch" href="/assets/js/475.4bbf0340.js"><link rel="prefetch" href="/assets/js/476.43ad6812.js"><link rel="prefetch" href="/assets/js/477.8ebfc8cd.js"><link rel="prefetch" href="/assets/js/478.f467a198.js"><link rel="prefetch" href="/assets/js/479.5fb38387.js"><link rel="prefetch" href="/assets/js/48.bec9faeb.js"><link rel="prefetch" href="/assets/js/480.065bc2f4.js"><link rel="prefetch" href="/assets/js/481.8e611064.js"><link rel="prefetch" href="/assets/js/482.deef708e.js"><link rel="prefetch" href="/assets/js/483.5a48543e.js"><link rel="prefetch" href="/assets/js/484.a7cb9e3e.js"><link rel="prefetch" href="/assets/js/485.39787d81.js"><link rel="prefetch" href="/assets/js/486.6fb72e6b.js"><link rel="prefetch" href="/assets/js/487.24cebed1.js"><link rel="prefetch" href="/assets/js/488.182ede16.js"><link rel="prefetch" href="/assets/js/489.00c3a33c.js"><link rel="prefetch" href="/assets/js/49.f271ac34.js"><link rel="prefetch" href="/assets/js/490.645a33e0.js"><link rel="prefetch" href="/assets/js/491.9fe59950.js"><link rel="prefetch" href="/assets/js/492.f29c2ae4.js"><link rel="prefetch" href="/assets/js/493.68095940.js"><link rel="prefetch" href="/assets/js/494.59430cc4.js"><link rel="prefetch" href="/assets/js/495.8a78704b.js"><link rel="prefetch" href="/assets/js/496.0d962a47.js"><link rel="prefetch" href="/assets/js/497.945b4bd3.js"><link rel="prefetch" href="/assets/js/498.90de0ef4.js"><link rel="prefetch" href="/assets/js/499.8e450b6e.js"><link rel="prefetch" href="/assets/js/5.2a4451ec.js"><link rel="prefetch" href="/assets/js/50.abf20f4e.js"><link rel="prefetch" href="/assets/js/500.aad8b0da.js"><link rel="prefetch" href="/assets/js/501.413d2da6.js"><link rel="prefetch" href="/assets/js/502.ddc19143.js"><link rel="prefetch" href="/assets/js/503.a19eff50.js"><link rel="prefetch" href="/assets/js/504.bb10c7b2.js"><link rel="prefetch" href="/assets/js/505.2fc64d4f.js"><link rel="prefetch" href="/assets/js/506.f933b9bf.js"><link rel="prefetch" href="/assets/js/507.ee0941f8.js"><link rel="prefetch" href="/assets/js/508.92e82e3e.js"><link rel="prefetch" href="/assets/js/509.57a208b7.js"><link rel="prefetch" href="/assets/js/51.65fecf2d.js"><link rel="prefetch" href="/assets/js/510.e67b123c.js"><link rel="prefetch" href="/assets/js/511.dd751df9.js"><link rel="prefetch" href="/assets/js/512.4a1b0e80.js"><link rel="prefetch" href="/assets/js/513.a093308f.js"><link rel="prefetch" href="/assets/js/514.dcd0f360.js"><link rel="prefetch" href="/assets/js/515.90705846.js"><link rel="prefetch" href="/assets/js/516.52b65bc6.js"><link rel="prefetch" href="/assets/js/517.bd0c91a6.js"><link rel="prefetch" href="/assets/js/518.aba293cf.js"><link rel="prefetch" href="/assets/js/519.9b2dd560.js"><link rel="prefetch" href="/assets/js/52.c17bb00d.js"><link rel="prefetch" href="/assets/js/520.8da09b22.js"><link rel="prefetch" href="/assets/js/521.b5667789.js"><link rel="prefetch" href="/assets/js/522.834a72cf.js"><link rel="prefetch" href="/assets/js/523.7968f7a9.js"><link rel="prefetch" href="/assets/js/524.c76179ea.js"><link rel="prefetch" href="/assets/js/525.7350bc28.js"><link rel="prefetch" href="/assets/js/526.2a0914f9.js"><link rel="prefetch" href="/assets/js/527.d1f03b8e.js"><link rel="prefetch" href="/assets/js/528.fee6a480.js"><link rel="prefetch" href="/assets/js/53.f1d91ca6.js"><link rel="prefetch" href="/assets/js/54.29e4a381.js"><link rel="prefetch" href="/assets/js/55.38876710.js"><link rel="prefetch" href="/assets/js/56.3a0eb98d.js"><link rel="prefetch" href="/assets/js/57.2f75fd9a.js"><link rel="prefetch" href="/assets/js/58.75b64521.js"><link rel="prefetch" href="/assets/js/59.7ac3776c.js"><link rel="prefetch" href="/assets/js/6.3450075a.js"><link rel="prefetch" href="/assets/js/60.53b7d88b.js"><link rel="prefetch" href="/assets/js/61.b70ccd57.js"><link rel="prefetch" href="/assets/js/62.eef65e9b.js"><link rel="prefetch" href="/assets/js/63.3a66528e.js"><link rel="prefetch" href="/assets/js/64.ca5c6060.js"><link rel="prefetch" href="/assets/js/65.5832f0ec.js"><link rel="prefetch" href="/assets/js/66.d486a91a.js"><link rel="prefetch" href="/assets/js/67.94140127.js"><link rel="prefetch" href="/assets/js/68.38ac76fc.js"><link rel="prefetch" href="/assets/js/69.1e5556d6.js"><link rel="prefetch" href="/assets/js/7.c5c54fb4.js"><link rel="prefetch" href="/assets/js/70.ce653ae5.js"><link rel="prefetch" href="/assets/js/71.dbdc4216.js"><link rel="prefetch" href="/assets/js/72.8010c02a.js"><link rel="prefetch" href="/assets/js/73.0478a06c.js"><link rel="prefetch" href="/assets/js/74.ba37e8e5.js"><link rel="prefetch" href="/assets/js/75.9e20de13.js"><link rel="prefetch" href="/assets/js/76.d444ceae.js"><link rel="prefetch" href="/assets/js/77.f0d86173.js"><link rel="prefetch" href="/assets/js/78.1f320f90.js"><link rel="prefetch" href="/assets/js/79.036924ec.js"><link rel="prefetch" href="/assets/js/8.536033df.js"><link rel="prefetch" href="/assets/js/80.293948a6.js"><link rel="prefetch" href="/assets/js/81.fcfc5c23.js"><link rel="prefetch" href="/assets/js/82.362d02a9.js"><link rel="prefetch" href="/assets/js/83.40c0f17c.js"><link rel="prefetch" href="/assets/js/84.e4ab62ab.js"><link rel="prefetch" href="/assets/js/85.a51ccec4.js"><link rel="prefetch" href="/assets/js/86.47e65cb0.js"><link rel="prefetch" href="/assets/js/87.afc9310c.js"><link rel="prefetch" href="/assets/js/88.e6fe60dc.js"><link rel="prefetch" href="/assets/js/89.572d5413.js"><link rel="prefetch" href="/assets/js/9.2e3ff783.js"><link rel="prefetch" href="/assets/js/90.b9f22784.js"><link rel="prefetch" href="/assets/js/91.fbe69360.js"><link rel="prefetch" href="/assets/js/92.295618c2.js"><link rel="prefetch" href="/assets/js/93.6c148bcd.js"><link rel="prefetch" href="/assets/js/94.df22e216.js"><link rel="prefetch" href="/assets/js/95.b136c253.js"><link rel="prefetch" href="/assets/js/96.2a84236c.js"><link rel="prefetch" href="/assets/js/97.6767cf86.js"><link rel="prefetch" href="/assets/js/98.77656225.js"><link rel="prefetch" href="/assets/js/99.902cfc13.js"><link rel="prefetch" href="/assets/js/vendors~docsearch.eff714eb.js">
<link rel="stylesheet" href="/assets/css/0.styles.ccadf850.css">
</head>
<body>
<div id="app" data-server-rendered="true"><div class="theme-container"><header class="navbar"><div class="sidebar-button"><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" role="img" viewBox="0 0 448 512" class="icon"><path fill="currentColor" d="M436 124H12c-6.627 0-12-5.373-12-12V80c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12z"></path></svg></div> <a href="/zh/" class="home-link router-link-active"><img src="/img/logo.png" alt=" " class="logo"></a> <div class="links"><div class="search-box"><input aria-label="Search" autocomplete="off" spellcheck="false" value=""> <!----></div> <nav class="nav-links can-hide"><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">文档</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/UserGuide/Master/Get Started/QuickStart.html" class="nav-link">In progress</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.11.x/Get Started/QuickStart.html" class="nav-link">V0.11.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.10.x/Get Started/QuickStart.html" class="nav-link">V0.10.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.9.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.9.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.8.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.8.x</a></li></ul></div></div><div class="nav-item"><a href="/zh/SystemDesign/Architecture/Architecture.html" class="nav-link">系统设计</a></div><div class="nav-item"><a href="/zh/Download/" class="nav-link">下载</a></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">社区</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="https://cwiki.apache.org/confluence/display/iotdb" class="nav-link external">
Wiki
<!----></a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Project Committers.html" class="nav-link">开发人员</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Powered By.html" class="nav-link">技术支持</a></li><li class="dropdown-item"><!----> <a href="/Community/Materials.html" class="nav-link">活动与报告</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Feedback.html" class="nav-link">交流与反馈</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">开发</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/Development/VoteRelease.html" class="nav-link">如何投票</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/HowToCommit.html" class="nav-link">如何提交代码</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/Committer.html" class="nav-link">成为Committer</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/ContributeGuide.html" class="nav-link">项目开发指南</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/format-changelist.html" class="nav-link">TsFile的更改列表</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/rpc-changelist.html" class="nav-link">RPC变更清单</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">ASF</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="http://www.apache.org/" class="nav-link external">
基金会
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/licenses/" class="nav-link external">
许可证
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/security/" class="nav-link external">
安全
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/sponsorship.html" class="nav-link external">
赞助
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/thanks.html" class="nav-link external">
致谢
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/events/current-event" class="nav-link external">
活动
<!----></a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">语言</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/SystemDesign/DataQuery/SeriesReader.html" class="nav-link">English</a></li><li class="dropdown-item"><!----> <a href="/zh/SystemDesign/DataQuery/SeriesReader.html" aria-current="page" class="nav-link router-link-exact-active router-link-active">简体中文</a></li></ul></div></div> <a href="https://github.com/apache/iotdb.git" target="_blank" rel="noopener noreferrer" class="repo-link">
gitHub
<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav></div></header> <div class="sidebar-mask"></div> <aside class="sidebar"><nav class="nav-links"><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">文档</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/UserGuide/Master/Get Started/QuickStart.html" class="nav-link">In progress</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.11.x/Get Started/QuickStart.html" class="nav-link">V0.11.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.10.x/Get Started/QuickStart.html" class="nav-link">V0.10.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.9.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.9.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.8.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.8.x</a></li></ul></div></div><div class="nav-item"><a href="/zh/SystemDesign/Architecture/Architecture.html" class="nav-link">系统设计</a></div><div class="nav-item"><a href="/zh/Download/" class="nav-link">下载</a></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">社区</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="https://cwiki.apache.org/confluence/display/iotdb" class="nav-link external">
Wiki
<!----></a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Project Committers.html" class="nav-link">开发人员</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Powered By.html" class="nav-link">技术支持</a></li><li class="dropdown-item"><!----> <a href="/Community/Materials.html" class="nav-link">活动与报告</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Feedback.html" class="nav-link">交流与反馈</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">开发</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/Development/VoteRelease.html" class="nav-link">如何投票</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/HowToCommit.html" class="nav-link">如何提交代码</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/Committer.html" class="nav-link">成为Committer</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/ContributeGuide.html" class="nav-link">项目开发指南</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/format-changelist.html" class="nav-link">TsFile的更改列表</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/rpc-changelist.html" class="nav-link">RPC变更清单</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">ASF</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="http://www.apache.org/" class="nav-link external">
基金会
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/licenses/" class="nav-link external">
许可证
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/security/" class="nav-link external">
安全
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/sponsorship.html" class="nav-link external">
赞助
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/thanks.html" class="nav-link external">
致谢
<!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/events/current-event" class="nav-link external">
活动
<!----></a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">语言</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/SystemDesign/DataQuery/SeriesReader.html" class="nav-link">English</a></li><li class="dropdown-item"><!----> <a href="/zh/SystemDesign/DataQuery/SeriesReader.html" aria-current="page" class="nav-link router-link-exact-active router-link-active">简体中文</a></li></ul></div></div> <a href="https://github.com/apache/iotdb.git" target="_blank" rel="noopener noreferrer" class="repo-link">
gitHub
<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav> <ul class="sidebar-links"><li><section class="sidebar-group depth-0"><p class="sidebar-heading"><span>系统设计</span> <!----></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>应用概览</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>TsFile</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>查询引擎</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>元数据管理</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>存储引擎</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading open"><span>数据查询</span> <span class="arrow down"></span></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/zh/SystemDesign/DataQuery/DataQuery.html" class="sidebar-link">数据查询</a></li><li><a href="/zh/SystemDesign/DataQuery/QueryFundamentals.html" class="sidebar-link">查询基础介绍</a></li><li><a href="/zh/SystemDesign/DataQuery/SeriesReader.html" aria-current="page" class="active sidebar-link">查询基础组件</a></li><li><a href="/zh/SystemDesign/DataQuery/RawDataQuery.html" class="sidebar-link">原始数据查询</a></li><li><a href="/zh/SystemDesign/DataQuery/AggregationQuery.html" class="sidebar-link">聚合查询</a></li><li><a href="/zh/SystemDesign/DataQuery/GroupByQuery.html" class="sidebar-link">降采样查询</a></li><li><a href="/zh/SystemDesign/DataQuery/LastQuery.html" class="sidebar-link">最近时间戳 Last 查询</a></li><li><a href="/zh/SystemDesign/DataQuery/AlignByDeviceQuery.html" class="sidebar-link">按设备对齐查询</a></li><li><a href="/zh/SystemDesign/DataQuery/FillFunction.html" class="sidebar-link">空值填充</a></li><li><a href="/zh/SystemDesign/DataQuery/GroupByFillQuery.html" class="sidebar-link">降采样补空值查询</a></li><li><a href="/zh/SystemDesign/DataQuery/OrderByTimeQuery.html" class="sidebar-link">按时间倒序查询</a></li></ul></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>工具</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>连接器</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>客户端</span> <span class="arrow right"></span></p> <!----></section></li></ul> </aside> <main class="page"> <div class="content content__default"><h1 id="查询基础组件"><a href="#查询基础组件" class="header-anchor">#</a> 查询基础组件</h1> <h2 id="设计原理"><a href="#设计原理" class="header-anchor">#</a> 设计原理</h2> <p>IoTDB server 模块共提供 3 种不同形式的针对单个时间序列的读取接口,以支持不同形式的查询。</p> <ul><li>原始数据查询接口,返回 BatchData,可带时间过滤条件或值过滤条件,两种过滤不可同时存在。</li> <li>聚合查询接口 (主要用于聚合查询和降采样查询)</li> <li>按递增时间戳查询对应值的接口(主要用于带值过滤的查询)</li></ul> <h2 id="相关接口"><a href="#相关接口" class="header-anchor">#</a> 相关接口</h2> <p>以上三种读取单个时间序列数据的方式对应代码里的三个接口</p> <h3 id="org-apache-iotdb-tsfile-read-reader-ibatchreader"><a href="#org-apache-iotdb-tsfile-read-reader-ibatchreader" class="header-anchor">#</a> org.apache.iotdb.tsfile.read.reader.IBatchReader</h3> <h4 id="主要方法"><a href="#主要方法" class="header-anchor">#</a> 主要方法</h4> <div class="language- line-numbers-mode"><pre class="language-text"><code>// 判断是否还有 BatchData
boolean hasNextBatch() throws IOException;
// 获得下一个 BatchData,并把游标后移
BatchData nextBatch() throws IOException;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><h4 id="使用流程"><a href="#使用流程" class="header-anchor">#</a> 使用流程</h4> <div class="language- line-numbers-mode"><pre class="language-text"><code>while (batchReader.hasNextBatch()) {
BatchData batchData = batchReader.nextBatch();
// use batchData to do some work
...
}
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br></div></div><h3 id="org-apache-iotdb-db-query-reader-series-iaggregatereader"><a href="#org-apache-iotdb-db-query-reader-series-iaggregatereader" class="header-anchor">#</a> org.apache.iotdb.db.query.reader.series.IAggregateReader</h3> <h4 id="主要方法-2"><a href="#主要方法-2" class="header-anchor">#</a> 主要方法</h4> <div class="language- line-numbers-mode"><pre class="language-text"><code>// 判断是否还有 Chunk
boolean hasNextChunk() throws IOException;
// 判断是否能够使用当前 Chunk 的统计信息
boolean canUseCurrentChunkStatistics();
// 获得当前 Chunk 的统计信息
Statistics currentChunkStatistics();
// 跳过当前 Chunk
void skipCurrentChunk();
// 判断当前Chunk是否还有下一个 Page
boolean hasNextPage() throws IOException;
// 判断能否使用当前 Page 的统计信息
boolean canUseCurrentPageStatistics() throws IOException;
// 获得当前 Page 的统计信息
Statistics currentPageStatistics() throws IOException;
// 跳过当前的 Page
void skipCurrentPage();
// 获得当前 Page 的数据
BatchData nextPage() throws IOException;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><h4 id="一般使用流程"><a href="#一般使用流程" class="header-anchor">#</a> 一般使用流程</h4> <div class="language- line-numbers-mode"><pre class="language-text"><code>while (aggregateReader.hasNextChunk()) {
if (aggregateReader.canUseCurrentChunkStatistics()) {
Statistics chunkStatistics = aggregateReader.currentChunkStatistics();
// 用 chunk 层的统计信息计算
...
aggregateReader.skipCurrentChunk();
continue;
}
// 把当前 chunk 中的 page 消耗完
while (aggregateReader.hasNextPage()) {
if (aggregateReader.canUseCurrentPageStatistics()) {
// 可以用统计信息
Statistics pageStatistic = aggregateReader.currentPageStatistics();
// 用 page 层的统计信息计算
...
aggregateReader.skipCurrentPage();
continue;
} else {
// 不能用统计信息,需要用数据计算
BatchData batchData = aggregateReader.nextOverlappedPage();
// 用 batchData 计算
...
}
}
}
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br></div></div><h3 id="org-apache-iotdb-db-query-reader-ireaderbytimestamp"><a href="#org-apache-iotdb-db-query-reader-ireaderbytimestamp" class="header-anchor">#</a> org.apache.iotdb.db.query.reader.IReaderByTimestamp</h3> <h4 id="主要方法-3"><a href="#主要方法-3" class="header-anchor">#</a> 主要方法</h4> <div class="language- line-numbers-mode"><pre class="language-text"><code>// 得到给定时间戳的值,如果不存在返回 null(要求传入的 timestamp 是递增的)
Object getValueInTimestamp(long timestamp) throws IOException;
// 给定一批递增时间戳的值,返回一批结果(减少方法调用次数)
Object[] getValuesInTimestamps(long[] timestamps) throws IOException;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><h4 id="一般使用流程-2"><a href="#一般使用流程-2" class="header-anchor">#</a> 一般使用流程</h4> <p>该接口在带值过滤的查询中被使用,TimeGenerator生成时间戳后,使用该接口获得该时间戳对应的value</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>Object value = readerByTimestamp.getValueInTimestamp(timestamp);
or
Object[] values = readerByTimestamp.getValueInTimestamp(timestamps);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><h2 id="具体实现类"><a href="#具体实现类" class="header-anchor">#</a> 具体实现类</h2> <p>上述三个接口都有其对应的实现类,由于以上三种查询有共性,我们设计了一个基础的 SeriesReader 工具类,封装了对于一个时间序列读取操作的基本方法,帮助实现以上三种接口。下面首先介绍 SeriesReader 的设计原理,然后再依次介绍三个接口的具体实现。</p> <h3 id="org-apache-iotdb-db-query-reader-series-seriesreader"><a href="#org-apache-iotdb-db-query-reader-series-seriesreader" class="header-anchor">#</a> org.apache.iotdb.db.query.reader.series.SeriesReader</h3> <h4 id="设计思想"><a href="#设计思想" class="header-anchor">#</a> 设计思想</h4> <p>背景知识:TsFile 文件(TsFileResource)解开后可以得到 ChunkMetadata,ChunkMetadata 解开后可以得到一堆 PageReader,PageReader 可以直接返回 BatchData 数据点。</p> <p>为了支持以上三种接口</p> <p>数据按照粒度从大到小分成四种:文件,Chunk,Page,相交数据点。在原始数据查询中,最大的数据块返回粒度是一个 page,如果一个 page 和其他 page 由于乱序写入相互覆盖了,就解开成数据点做合并。聚合查询中优先使用 Chunk 的统计信息,其次是 Page 的统计信息,最后是相交数据点。</p> <p>设计原则是能用粒度大的就不用粒度小的。</p> <p>首先介绍一下SeriesReader里的几个重要字段</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>
/*
* 文件层
*/
private final List&lt;TsFileResource&gt; seqFileResource;
顺序文件列表,因为顺序文件本身就保证有序,且时间戳互不重叠,只需使用List进行存储
private final PriorityQueue&lt;TsFileResource&gt; unseqFileResource;
乱序文件列表,因为乱序文件互相之间不保证顺序性,且可能有重叠,为了保证顺序,使用优先队列进行存储
/*
* chunk 层
*
* 三个字段之间数据永远不重复,first 永远是第一个(开始时间最小)
*/
private ChunkMetaData firstChunkMetaData;
填充 chunk 层时优先填充此字段,保证这个 chunk 具有当前最小开始时间
private final List&lt;ChunkMetaData&gt; seqChunkMetadatas;
顺序文件解开后得到的 ChunkMetaData 存放在此,本身有序且互不重叠,所以使用 List 存储
private final PriorityQueue&lt;ChunkMetaData&gt; unseqChunkMetadatas;
乱序文件解开后得到的 ChunkMetaData 存放在此,互相之间可能有重叠,为了保证顺序,使用优先队列进行存储
/*
* page 层
*
* 两个字段之间数据永远不重复,first 永远是第一个(开始时间最小)
*/
private VersionPageReader firstPageReader;
开始时间最小的 page reader
private PriorityQueue&lt;VersionPageReader&gt; cachedPageReaders;
当前获得的所有 page reader,按照每个 page 的起始时间进行排序
/*
* 相交数据点层
*/
private PriorityMergeReader mergeReader;
本质上是多个带优先级的 page,按时间戳从低到高输出数据点,时间戳相同时,保留优先级高的
/*
* 相交数据点产出结果的缓存
*/
private boolean hasCachedNextOverlappedPage;
是否缓存了下一个batch
private BatchData cachedBatchData;
缓存的下一个batch的引用
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br></div></div><p>下面介绍一下SeriesReader里的重要方法</p> <h4 id="hasnextchunk"><a href="#hasnextchunk" class="header-anchor">#</a> hasNextChunk()</h4> <ul><li><p>主要功能:判断该时间序列还有没有下一个chunk。</p></li> <li><p>约束:在调用这个方法前,需要保证 <code>SeriesReader</code> 内已经没有 page 和 数据点 层级的数据了,也就是之前解开的 chunk 都消耗完了。</p></li> <li><p>实现:如果 <code>firstChunkMetaData</code> 不为空,则代表当前已经缓存了第一个 <code>ChunkMetaData</code>,且未被使用,直接返回<code>true</code></p> <p>尝试去解开第一个顺序文件和第一个乱序文件,填充 chunk 层。并解开与 <code>firstChunkMetadata</code> 相重合的所有文件。</p></li></ul> <h4 id="ischunkoverlapped"><a href="#ischunkoverlapped" class="header-anchor">#</a> isChunkOverlapped()</h4> <ul><li><p>主要功能:判断当前的 chunk 有没有与其他 Chunk 有重叠</p></li> <li><p>约束:在调用这个方法前,需要保证 chunk 层已经缓存了 <code>firstChunkMetadata</code>,也就是调用了 hasNextChunk() 并且为 true。</p></li> <li><p>实现:直接把 <code>firstChunkMetadata</code><code>seqChunkMetadatas</code><code>unseqChunkMetadatas</code> 相比较。因为此前已经保证所有和 <code>firstChunkMetadata</code> 相交的文件都被解开了。</p></li></ul> <h4 id="currentchunkstatistics"><a href="#currentchunkstatistics" class="header-anchor">#</a> currentChunkStatistics()</h4> <p>返回 <code>firstChunkMetaData</code> 的统计信息。</p> <h4 id="skipcurrentchunk"><a href="#skipcurrentchunk" class="header-anchor">#</a> skipCurrentChunk()</h4> <p>跳过当前 chunk。只需要将<code>firstChunkMetaData</code>置为<code>null</code></p> <h4 id="hasnextpage"><a href="#hasnextpage" class="header-anchor">#</a> hasNextPage()</h4> <ul><li><p>主要功能:判断 SeriesReader 中还有没有已经解开的 page,如果有相交的 page,就构造 <code>cachedBatchData</code> 并缓存,否则缓存 <code>firstPageReader</code></p></li> <li><p>实现:如果已经缓存了 <code>cachedBatchData</code> 就直接返回。如果有相交数据点,就构造 <code>cachedBatchData</code>。如果已经缓存了 <code>firstPageReader</code>,就直接返回。</p> <p>如果当前的 <code>firstChunkMetadata</code> 还没有解开,就解开与之重叠的所有 ChunkMetadata,构造 firstPageReader。</p> <p>判断,如果 <code>firstPageReader</code><code>cachedPageReaders</code> 相交,则构造 <code>cachedBatchData</code>,否则直接返回。</p></li></ul> <h4 id="ispageoverlapped"><a href="#ispageoverlapped" class="header-anchor">#</a> isPageOverlapped()</h4> <ul><li><p>主要功能:判断当前的 page 有没有与其他 page 有重叠</p></li> <li><p>约束:在调用这个方法前,需要保证调用了 hasNextPage() 并且为 true。也就是,有可能缓存了一个相交的 <code>cachedBatchData</code>,或者缓存了不相交的 <code>firstPageReader</code></p></li> <li><p>实现:先判断有没有 <code>cachedBatchData</code>,如果没有,就说明当前 page 不相交,则 <code>mergeReader</code> 里没数据。再判断 <code>firstPageReader</code> 是否与 <code>cachedPageReaders</code> 中的 page 相交。</p></li></ul> <h4 id="currentpagestatistics"><a href="#currentpagestatistics" class="header-anchor">#</a> currentPageStatistics()</h4> <p>返回 <code>firstPageReader</code> 的统计信息。</p> <h4 id="skipcurrentpage"><a href="#skipcurrentpage" class="header-anchor">#</a> skipCurrentPage()</h4> <p>跳过当前Page。只需要将 <code>firstPageReader</code> 置为 null。</p> <h4 id="nextpage"><a href="#nextpage" class="header-anchor">#</a> nextPage()</h4> <ul><li><p>主要功能:返回下一个相交或不相交的 page</p></li> <li><p>约束:在调用这个方法前,需要保证调用了 hasNextPage() 并且为 true。也就是,有可能缓存了一个相交的 <code>cachedBatchData</code>,或者缓存了不相交的 <code>firstPageReader</code></p></li> <li><p>实现:如果 <code>hasCachedNextOverlappedPage</code> 为 true,说明缓存了一个相交的 page,直接返回 <code>cachedBatchData</code>。否则当前 page 不相交,直接从 firstPageReader 里拿当前 page 的数据。</p></li></ul> <h4 id="hasnextoverlappedpage"><a href="#hasnextoverlappedpage" class="header-anchor">#</a> hasNextOverlappedPage()</h4> <ul><li><p>主要功能:内部方法,用来判断当前有没有重叠的数据,并且构造相交的 page 并缓存。</p></li> <li><p>实现:如果 <code>hasCachedNextOverlappedPage</code><code>true</code>,直接返回 <code>true</code></p> <p>否则,先调用 <code>tryToPutAllDirectlyOverlappedPageReadersIntoMergeReader()</code> 方法,将 <code>cachedPageReaders</code> 中所有与 <code>firstPageReader</code> 有重叠的放进 <code>mergeReader</code> 里。<code>mergeReader</code> 里维护了一个 <code>currentLargestEndTime</code> 变量,每次添加进新的 Reader 时被更新,用以记录当前添加进 <code>mergeReader</code> 的 page 的最大结束时间。
然后先从<code>mergeReader</code>里取出当前最大的结束时间,作为第一批数据的结束时间,记为<code>currentPageEndTime</code>。接着去遍历<code>mergeReader</code>,直到当前的时间戳大于<code>currentPageEndTime</code></p> <p>每从 mergeReader 移出一个点前,我们先要判断是否有与当前时间戳重叠的file或者chunk或者page(这里之所以还要再做一次判断,是因为,比如当前page是1-30,和他直接相交的page是20-50,还有一个page是40-60,每取一个点判断一次是想把40-60解开),如果有,解开相应的file或者chunk或者page,并将其放入<code>mergeReader</code>。完成重叠的判断后,从<code>mergeReader</code>中取出相应数据。</p> <p>完成迭代后将获得数据缓存在 <code>cachedBatchData</code> 中,并将 <code>hasCachedNextOverlappedPage</code> 置为 <code>true</code></p></li></ul> <h4 id="nextoverlappedpage"><a href="#nextoverlappedpage" class="header-anchor">#</a> nextOverlappedPage()</h4> <p>将缓存的<code>cachedBatchData</code>返回,并将<code>hasCachedNextOverlappedPage</code>置为<code>false</code></p> <h3 id="org-apache-iotdb-db-query-reader-series-seriesrawdatabatchreader"><a href="#org-apache-iotdb-db-query-reader-series-seriesrawdatabatchreader" class="header-anchor">#</a> org.apache.iotdb.db.query.reader.series.SeriesRawDataBatchReader</h3> <p><code>SeriesRawDataBatchReader</code>实现了<code>IBatchReader</code></p> <p>其方法<code>hasNextBatch()</code>的核心判断流程是</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>// 有缓存了 batch,直接返回
if (hasCachedBatchData) {
return true;
}
/*
* 如果 SeriesReader 里还有 page,返回 page
*/
if (readPageData()) {
hasCachedBatchData = true;
return true;
}
/*
* 如果有 chunk,并且有 page,返回 page
*/
while (seriesReader.hasNextChunk()) {
if (readPageData()) {
hasCachedBatchData = true;
return true;
}
}
return hasCachedBatchData;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h3 id="org-apache-iotdb-db-query-reader-series-seriesreaderbytimestamp"><a href="#org-apache-iotdb-db-query-reader-series-seriesreaderbytimestamp" class="header-anchor">#</a> org.apache.iotdb.db.query.reader.series.SeriesReaderByTimestamp</h3> <p><code>SeriesReaderByTimestamp</code> 实现了 <code>IReaderByTimestamp</code></p> <p>设计思想:当给一个时间戳要查询值时,这个时间戳可以转化为一个 time &gt;= x 的过滤条件。不断更新这个过滤条件,并且跳过不满足的文件,chunk 和 page。</p> <p>实现方式:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>/*
* 优先判断下一个 page 有没有当前所查时间,能跳过就跳过
*/
if (readPageData(timestamp)) {
return true;
}
/*
* 判断下一个 chunk 有没有当前所查时间,能跳过就跳过
*/
while (seriesReader.hasNextChunk()) {
Statistics statistics = seriesReader.currentChunkStatistics();
if (!satisfyTimeFilter(statistics)) {
seriesReader.skipCurrentChunk();
continue;
}
/*
* chunk 不能跳过,继续到 chunk 里检查 page
*/
if (readPageData(timestamp)) {
return true;
}
}
return false;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h3 id="org-apache-iotdb-db-query-reader-series-seriesaggregatereader"><a href="#org-apache-iotdb-db-query-reader-series-seriesaggregatereader" class="header-anchor">#</a> org.apache.iotdb.db.query.reader.series.SeriesAggregateReader</h3> <p><code>SeriesAggregateReader</code> 实现了 <code>IAggregateReader</code></p> <p><code>IAggregateReader</code>的大部分接口方法都在<code>SeriesReader</code>有对应实现,除了<code>canUseCurrentChunkStatistics()</code><code>canUseCurrentPageStatistics()</code>两个方法。</p> <h4 id="canusecurrentchunkstatistics"><a href="#canusecurrentchunkstatistics" class="header-anchor">#</a> canUseCurrentChunkStatistics()</h4> <p>设计思想:可以用统计信息的条件是当前 chunk 不重叠,并且满足过滤条件。</p> <p>先调用<code>SeriesReader</code><code>currentChunkStatistics()</code>方法,获得当前chunk的统计信息,再调用<code>SeriesReader</code><code>isChunkOverlapped()</code>方法判断当前chunk是否重叠,如果当前chunk不重叠,且其统计信息满足过滤条件,则返回<code>true</code>,否则返回<code>false</code></p> <h4 id="canusecurrentpagestatistics"><a href="#canusecurrentpagestatistics" class="header-anchor">#</a> canUseCurrentPageStatistics()</h4> <p>设计思想:可以用统计信息的条件是当前 page 不重叠,并且满足过滤条件。</p> <p>先调用<code>SeriesReader</code><code>currentPageStatistics()</code> 方法,获得当前page的统计信息,再调用<code>SeriesReader</code><code>isPageOverlapped()</code> 方法判断当前 page 是否重叠,如果当前page不重叠,且其统计信息满足过滤条件,则返回<code>true</code>,否则返回<code>false</code></p></div> <div class="page-nav"><p class="inner"><span class="prev">
<a href="/zh/SystemDesign/DataQuery/QueryFundamentals.html" class="prev">
查询基础介绍
</a></span> <span class="next"><a href="/zh/SystemDesign/DataQuery/RawDataQuery.html">
原始数据查询
</a>
</span></p></div> <p style="text-align: center;">Copyright © 2021 The Apache Software Foundation.<br>
Apache and the Apache feather logo are trademarks of The Apache Software Foundation</p> <p style="text-align: center; margin-top: 10px; color: #444">
Contact us: Join QQ Group 659990460 | Add friend <i>tietouqiao</i> and be invited to Wechat Group<br>
see <a href="https://github.com/apache/iotdb/issues/1995">Join the community</a> for more</p></main></div><div class="global-ui"></div></div>
<script src="/assets/js/app.0ce1fe55.js" defer></script><script src="/assets/js/3.5626571b.js" defer></script><script src="/assets/js/297.9c1e3937.js" defer></script>
</body>
</html>