<!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 1.7.1">
    <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.679f71b6.css" as="style"><link rel="preload" href="/assets/js/app.ee472f44.js" as="script"><link rel="preload" href="/assets/js/3.49f0f20a.js" as="script"><link rel="preload" href="/assets/js/289.8990a52d.js" as="script"><link rel="prefetch" href="/assets/js/10.a9e4399a.js"><link rel="prefetch" href="/assets/js/100.68c72120.js"><link rel="prefetch" href="/assets/js/101.b6fa0a59.js"><link rel="prefetch" href="/assets/js/102.a64e2bb2.js"><link rel="prefetch" href="/assets/js/103.3e232964.js"><link rel="prefetch" href="/assets/js/104.12a0c146.js"><link rel="prefetch" href="/assets/js/105.c82addea.js"><link rel="prefetch" href="/assets/js/106.d95539e1.js"><link rel="prefetch" href="/assets/js/107.3a8e4204.js"><link rel="prefetch" href="/assets/js/108.445910dc.js"><link rel="prefetch" href="/assets/js/109.e592a10a.js"><link rel="prefetch" href="/assets/js/11.1a825151.js"><link rel="prefetch" href="/assets/js/110.f2ff7f26.js"><link rel="prefetch" href="/assets/js/111.ce7b4bb8.js"><link rel="prefetch" href="/assets/js/112.c0fb665c.js"><link rel="prefetch" href="/assets/js/113.27feecaf.js"><link rel="prefetch" href="/assets/js/114.4610bfa2.js"><link rel="prefetch" href="/assets/js/115.0857c1d6.js"><link rel="prefetch" href="/assets/js/116.530d568b.js"><link rel="prefetch" href="/assets/js/117.9deade83.js"><link rel="prefetch" href="/assets/js/118.cbb62265.js"><link rel="prefetch" href="/assets/js/119.8822d43b.js"><link rel="prefetch" href="/assets/js/12.4679de68.js"><link rel="prefetch" href="/assets/js/120.355ddd53.js"><link rel="prefetch" href="/assets/js/121.94505f4a.js"><link rel="prefetch" href="/assets/js/122.6c825584.js"><link rel="prefetch" href="/assets/js/123.d2965d60.js"><link rel="prefetch" href="/assets/js/124.bb17af3e.js"><link rel="prefetch" href="/assets/js/125.a523475b.js"><link rel="prefetch" href="/assets/js/126.309eb2a0.js"><link rel="prefetch" href="/assets/js/127.31f131d5.js"><link rel="prefetch" href="/assets/js/128.d6961094.js"><link rel="prefetch" href="/assets/js/129.9f80c586.js"><link rel="prefetch" href="/assets/js/13.821d2576.js"><link rel="prefetch" href="/assets/js/130.8b3034e2.js"><link rel="prefetch" href="/assets/js/131.5c952a0b.js"><link rel="prefetch" href="/assets/js/132.9b312915.js"><link rel="prefetch" href="/assets/js/133.229545d4.js"><link rel="prefetch" href="/assets/js/134.6ef84d4d.js"><link rel="prefetch" href="/assets/js/135.63dcccc3.js"><link rel="prefetch" href="/assets/js/136.693bbb9e.js"><link rel="prefetch" href="/assets/js/137.065787a2.js"><link rel="prefetch" href="/assets/js/138.199d56aa.js"><link rel="prefetch" href="/assets/js/139.93368911.js"><link rel="prefetch" href="/assets/js/14.f2409887.js"><link rel="prefetch" href="/assets/js/140.cb3339d6.js"><link rel="prefetch" href="/assets/js/141.0ffa040d.js"><link rel="prefetch" href="/assets/js/142.c3e197d4.js"><link rel="prefetch" href="/assets/js/143.9e4dc6ae.js"><link rel="prefetch" href="/assets/js/144.27249482.js"><link rel="prefetch" href="/assets/js/145.f9305e04.js"><link rel="prefetch" href="/assets/js/146.a953796c.js"><link rel="prefetch" href="/assets/js/147.5ffa8a4e.js"><link rel="prefetch" href="/assets/js/148.5f5c0ad8.js"><link rel="prefetch" href="/assets/js/149.6690aae1.js"><link rel="prefetch" href="/assets/js/15.9354febe.js"><link rel="prefetch" href="/assets/js/150.36dae2d3.js"><link rel="prefetch" href="/assets/js/151.2ca29374.js"><link rel="prefetch" href="/assets/js/152.fceb9b61.js"><link rel="prefetch" href="/assets/js/153.93489dbc.js"><link rel="prefetch" href="/assets/js/154.d9c14ff8.js"><link rel="prefetch" href="/assets/js/155.b6eec7f7.js"><link rel="prefetch" href="/assets/js/156.8718f8bc.js"><link rel="prefetch" href="/assets/js/157.8484231e.js"><link rel="prefetch" href="/assets/js/158.d1755131.js"><link rel="prefetch" href="/assets/js/159.8a8be7d5.js"><link rel="prefetch" href="/assets/js/16.590590ab.js"><link rel="prefetch" href="/assets/js/160.67e2efd2.js"><link rel="prefetch" href="/assets/js/161.0e22ffff.js"><link rel="prefetch" href="/assets/js/162.f47c5fdc.js"><link rel="prefetch" href="/assets/js/163.da74b426.js"><link rel="prefetch" href="/assets/js/164.f88f06d5.js"><link rel="prefetch" href="/assets/js/165.9a1b5b41.js"><link rel="prefetch" href="/assets/js/166.8832a7a4.js"><link rel="prefetch" href="/assets/js/167.ff58fb1f.js"><link rel="prefetch" href="/assets/js/168.9a351c30.js"><link rel="prefetch" href="/assets/js/169.23c06c42.js"><link rel="prefetch" href="/assets/js/17.4cb5664d.js"><link rel="prefetch" href="/assets/js/170.ea0af6cf.js"><link rel="prefetch" href="/assets/js/171.e11e1bb7.js"><link rel="prefetch" href="/assets/js/172.273f4d56.js"><link rel="prefetch" href="/assets/js/173.fca03089.js"><link rel="prefetch" href="/assets/js/174.434334ff.js"><link rel="prefetch" href="/assets/js/175.a8acb6b2.js"><link rel="prefetch" href="/assets/js/176.a1c55473.js"><link rel="prefetch" href="/assets/js/177.ebb38cec.js"><link rel="prefetch" href="/assets/js/178.79b8a327.js"><link rel="prefetch" href="/assets/js/179.6319af14.js"><link rel="prefetch" href="/assets/js/18.f5fe433e.js"><link rel="prefetch" href="/assets/js/180.28a1d783.js"><link rel="prefetch" href="/assets/js/181.a29f39c5.js"><link rel="prefetch" href="/assets/js/182.9f3d9c76.js"><link rel="prefetch" href="/assets/js/183.338ae9a8.js"><link rel="prefetch" href="/assets/js/184.18c28159.js"><link rel="prefetch" href="/assets/js/185.05381100.js"><link rel="prefetch" href="/assets/js/186.ce9412eb.js"><link rel="prefetch" href="/assets/js/187.30a80942.js"><link rel="prefetch" href="/assets/js/188.5a77f986.js"><link rel="prefetch" href="/assets/js/189.f34dc967.js"><link rel="prefetch" href="/assets/js/19.d02f7224.js"><link rel="prefetch" href="/assets/js/190.d9762047.js"><link rel="prefetch" href="/assets/js/191.8c52689f.js"><link rel="prefetch" href="/assets/js/192.10ae9786.js"><link rel="prefetch" href="/assets/js/193.4a83ff5f.js"><link rel="prefetch" href="/assets/js/194.1d9f888b.js"><link rel="prefetch" href="/assets/js/195.ac95d80c.js"><link rel="prefetch" href="/assets/js/196.305a7cc8.js"><link rel="prefetch" href="/assets/js/197.3950b155.js"><link rel="prefetch" href="/assets/js/198.60367e76.js"><link rel="prefetch" href="/assets/js/199.a5eec1cf.js"><link rel="prefetch" href="/assets/js/20.02900ba2.js"><link rel="prefetch" href="/assets/js/200.7b42f970.js"><link rel="prefetch" href="/assets/js/201.c176b7b8.js"><link rel="prefetch" href="/assets/js/202.eb6989b5.js"><link rel="prefetch" href="/assets/js/203.77522ed7.js"><link rel="prefetch" href="/assets/js/204.d5e4c11b.js"><link rel="prefetch" href="/assets/js/205.b174d51b.js"><link rel="prefetch" href="/assets/js/206.4c489028.js"><link rel="prefetch" href="/assets/js/207.afdf032a.js"><link rel="prefetch" href="/assets/js/208.e5a0bdd5.js"><link rel="prefetch" href="/assets/js/209.67c9cab8.js"><link rel="prefetch" href="/assets/js/21.3b6ef7f6.js"><link rel="prefetch" href="/assets/js/210.99085605.js"><link rel="prefetch" href="/assets/js/211.62045ced.js"><link rel="prefetch" href="/assets/js/212.5d4b9b33.js"><link rel="prefetch" href="/assets/js/213.8d2fc243.js"><link rel="prefetch" href="/assets/js/214.081b8259.js"><link rel="prefetch" href="/assets/js/215.a9c42b7b.js"><link rel="prefetch" href="/assets/js/216.e4177064.js"><link rel="prefetch" href="/assets/js/217.00d389be.js"><link rel="prefetch" href="/assets/js/218.53691557.js"><link rel="prefetch" href="/assets/js/219.fce8476d.js"><link rel="prefetch" href="/assets/js/22.ab7a2af8.js"><link rel="prefetch" href="/assets/js/220.8ca717ad.js"><link rel="prefetch" href="/assets/js/221.b774095e.js"><link rel="prefetch" href="/assets/js/222.abb49f0a.js"><link rel="prefetch" href="/assets/js/223.506eb112.js"><link rel="prefetch" href="/assets/js/224.7e33133f.js"><link rel="prefetch" href="/assets/js/225.4443cf9b.js"><link rel="prefetch" href="/assets/js/226.5d64564f.js"><link rel="prefetch" href="/assets/js/227.e647cf42.js"><link rel="prefetch" href="/assets/js/228.7b8e1561.js"><link rel="prefetch" href="/assets/js/229.c6b936b3.js"><link rel="prefetch" href="/assets/js/23.b428286f.js"><link rel="prefetch" href="/assets/js/230.484dfbbc.js"><link rel="prefetch" href="/assets/js/231.04cb07f3.js"><link rel="prefetch" href="/assets/js/232.cb5f7cf4.js"><link rel="prefetch" href="/assets/js/233.fd5563aa.js"><link rel="prefetch" href="/assets/js/234.bf0c8bd7.js"><link rel="prefetch" href="/assets/js/235.c910d0ff.js"><link rel="prefetch" href="/assets/js/236.2fa96a32.js"><link rel="prefetch" href="/assets/js/237.4d40bac8.js"><link rel="prefetch" href="/assets/js/238.8f8a5f39.js"><link rel="prefetch" href="/assets/js/239.8c8e2f64.js"><link rel="prefetch" href="/assets/js/24.a3749d36.js"><link rel="prefetch" href="/assets/js/240.b662bcd8.js"><link rel="prefetch" href="/assets/js/241.04b9e3ed.js"><link rel="prefetch" href="/assets/js/242.bae1b833.js"><link rel="prefetch" href="/assets/js/243.174da90a.js"><link rel="prefetch" href="/assets/js/244.1ad856fc.js"><link rel="prefetch" href="/assets/js/245.a622849c.js"><link rel="prefetch" href="/assets/js/246.dc04cc61.js"><link rel="prefetch" href="/assets/js/247.d9f48a2f.js"><link rel="prefetch" href="/assets/js/248.85018b5a.js"><link rel="prefetch" href="/assets/js/249.6ba9e6c7.js"><link rel="prefetch" href="/assets/js/25.bc6a97e8.js"><link rel="prefetch" href="/assets/js/250.9ca65c13.js"><link rel="prefetch" href="/assets/js/251.8f4abe5e.js"><link rel="prefetch" href="/assets/js/252.cb8b4901.js"><link rel="prefetch" href="/assets/js/253.e43c464a.js"><link rel="prefetch" href="/assets/js/254.bc5748be.js"><link rel="prefetch" href="/assets/js/255.ad9c3e74.js"><link rel="prefetch" href="/assets/js/256.48bf6b1c.js"><link rel="prefetch" href="/assets/js/257.aae9e4a7.js"><link rel="prefetch" href="/assets/js/258.d27a0224.js"><link rel="prefetch" href="/assets/js/259.8b338cff.js"><link rel="prefetch" href="/assets/js/26.81ae73cb.js"><link rel="prefetch" href="/assets/js/260.9302e533.js"><link rel="prefetch" href="/assets/js/261.ea1ed48a.js"><link rel="prefetch" href="/assets/js/262.08d81cca.js"><link rel="prefetch" href="/assets/js/263.c2598230.js"><link rel="prefetch" href="/assets/js/264.89fadf4b.js"><link rel="prefetch" href="/assets/js/265.9e7e3b87.js"><link rel="prefetch" href="/assets/js/266.63098760.js"><link rel="prefetch" href="/assets/js/267.df285aaf.js"><link rel="prefetch" href="/assets/js/268.56ef99a0.js"><link rel="prefetch" href="/assets/js/269.86c3bd00.js"><link rel="prefetch" href="/assets/js/27.5361988c.js"><link rel="prefetch" href="/assets/js/270.69d8c77d.js"><link rel="prefetch" href="/assets/js/271.49550e05.js"><link rel="prefetch" href="/assets/js/272.bf7fe25a.js"><link rel="prefetch" href="/assets/js/273.bac87430.js"><link rel="prefetch" href="/assets/js/274.1a5b6778.js"><link rel="prefetch" href="/assets/js/275.59d1fe0c.js"><link rel="prefetch" href="/assets/js/276.c21f1bb7.js"><link rel="prefetch" href="/assets/js/277.3416c059.js"><link rel="prefetch" href="/assets/js/278.1e47cbc9.js"><link rel="prefetch" href="/assets/js/279.a285ca6b.js"><link rel="prefetch" href="/assets/js/28.902cf242.js"><link rel="prefetch" href="/assets/js/280.b1cfd58b.js"><link rel="prefetch" href="/assets/js/281.5014dd8c.js"><link rel="prefetch" href="/assets/js/282.f46c3f5f.js"><link rel="prefetch" href="/assets/js/283.c8fa806b.js"><link rel="prefetch" href="/assets/js/284.1bca3237.js"><link rel="prefetch" href="/assets/js/285.ca102a1f.js"><link rel="prefetch" href="/assets/js/286.312b549d.js"><link rel="prefetch" href="/assets/js/287.56daf71d.js"><link rel="prefetch" href="/assets/js/288.4d6ee237.js"><link rel="prefetch" href="/assets/js/29.8878a84b.js"><link rel="prefetch" href="/assets/js/290.79c4d4bb.js"><link rel="prefetch" href="/assets/js/291.e39a8f59.js"><link rel="prefetch" href="/assets/js/292.09b1dbf3.js"><link rel="prefetch" href="/assets/js/293.c11758cc.js"><link rel="prefetch" href="/assets/js/294.efe1c620.js"><link rel="prefetch" href="/assets/js/295.9a4ce682.js"><link rel="prefetch" href="/assets/js/296.5d55e2b4.js"><link rel="prefetch" href="/assets/js/297.0c74b494.js"><link rel="prefetch" href="/assets/js/298.61015025.js"><link rel="prefetch" href="/assets/js/299.95b2a709.js"><link rel="prefetch" href="/assets/js/30.144a5c6c.js"><link rel="prefetch" href="/assets/js/300.1ded6f5a.js"><link rel="prefetch" href="/assets/js/301.0c60ca57.js"><link rel="prefetch" href="/assets/js/302.a4e4ce29.js"><link rel="prefetch" href="/assets/js/303.f51290d8.js"><link rel="prefetch" href="/assets/js/304.5b9d354a.js"><link rel="prefetch" href="/assets/js/305.4fc3fa36.js"><link rel="prefetch" href="/assets/js/306.d2ccf3d8.js"><link rel="prefetch" href="/assets/js/307.137ddc6c.js"><link rel="prefetch" href="/assets/js/308.d093842e.js"><link rel="prefetch" href="/assets/js/309.8d85e9c5.js"><link rel="prefetch" href="/assets/js/31.03034f21.js"><link rel="prefetch" href="/assets/js/310.610cadf2.js"><link rel="prefetch" href="/assets/js/311.3f9bc269.js"><link rel="prefetch" href="/assets/js/312.ac085561.js"><link rel="prefetch" href="/assets/js/313.39e131a4.js"><link rel="prefetch" href="/assets/js/314.62ae7afd.js"><link rel="prefetch" href="/assets/js/315.312dd0ad.js"><link rel="prefetch" href="/assets/js/316.3daa3b97.js"><link rel="prefetch" href="/assets/js/317.385cce00.js"><link rel="prefetch" href="/assets/js/318.6e75f908.js"><link rel="prefetch" href="/assets/js/319.4a8516ae.js"><link rel="prefetch" href="/assets/js/32.bad93e79.js"><link rel="prefetch" href="/assets/js/320.e6ea8799.js"><link rel="prefetch" href="/assets/js/321.c192a35e.js"><link rel="prefetch" href="/assets/js/322.c675d3fd.js"><link rel="prefetch" href="/assets/js/323.cf867cd9.js"><link rel="prefetch" href="/assets/js/324.38af9dd2.js"><link rel="prefetch" href="/assets/js/325.dd39b2de.js"><link rel="prefetch" href="/assets/js/326.b3197783.js"><link rel="prefetch" href="/assets/js/327.7ab3256f.js"><link rel="prefetch" href="/assets/js/328.a51703c6.js"><link rel="prefetch" href="/assets/js/329.d4f2f214.js"><link rel="prefetch" href="/assets/js/33.00e7d6b5.js"><link rel="prefetch" href="/assets/js/330.1fb7bbad.js"><link rel="prefetch" href="/assets/js/331.52605dbf.js"><link rel="prefetch" href="/assets/js/332.58cff2f4.js"><link rel="prefetch" href="/assets/js/333.fa7136ab.js"><link rel="prefetch" href="/assets/js/334.0de0062b.js"><link rel="prefetch" href="/assets/js/335.a5e18bb9.js"><link rel="prefetch" href="/assets/js/336.448ec9fa.js"><link rel="prefetch" href="/assets/js/337.c877f6df.js"><link rel="prefetch" href="/assets/js/338.e071e415.js"><link rel="prefetch" href="/assets/js/339.194f47f4.js"><link rel="prefetch" href="/assets/js/34.44ac5494.js"><link rel="prefetch" href="/assets/js/340.5755d00b.js"><link rel="prefetch" href="/assets/js/341.070a9aed.js"><link rel="prefetch" href="/assets/js/342.35edcb5e.js"><link rel="prefetch" href="/assets/js/343.a86abe3e.js"><link rel="prefetch" href="/assets/js/344.22456a86.js"><link rel="prefetch" href="/assets/js/345.054131fa.js"><link rel="prefetch" href="/assets/js/346.d850e5ce.js"><link rel="prefetch" href="/assets/js/347.7b8936a1.js"><link rel="prefetch" href="/assets/js/348.5ee2b670.js"><link rel="prefetch" href="/assets/js/349.f37573c7.js"><link rel="prefetch" href="/assets/js/35.7f32ce73.js"><link rel="prefetch" href="/assets/js/350.312ee288.js"><link rel="prefetch" href="/assets/js/351.aabc93dc.js"><link rel="prefetch" href="/assets/js/352.99aa4418.js"><link rel="prefetch" href="/assets/js/353.9c90d422.js"><link rel="prefetch" href="/assets/js/354.8a7c72b5.js"><link rel="prefetch" href="/assets/js/355.1008fd17.js"><link rel="prefetch" href="/assets/js/356.546f7242.js"><link rel="prefetch" href="/assets/js/357.3f84c383.js"><link rel="prefetch" href="/assets/js/358.57ab0f48.js"><link rel="prefetch" href="/assets/js/359.715ee9c0.js"><link rel="prefetch" href="/assets/js/36.d1e9d19f.js"><link rel="prefetch" href="/assets/js/360.92093399.js"><link rel="prefetch" href="/assets/js/361.8e8a2657.js"><link rel="prefetch" href="/assets/js/362.c6796915.js"><link rel="prefetch" href="/assets/js/363.e17af86a.js"><link rel="prefetch" href="/assets/js/364.6274b87c.js"><link rel="prefetch" href="/assets/js/365.211ac0fc.js"><link rel="prefetch" href="/assets/js/366.e5297f1f.js"><link rel="prefetch" href="/assets/js/367.d778a1f0.js"><link rel="prefetch" href="/assets/js/368.d55765fc.js"><link rel="prefetch" href="/assets/js/369.d357817a.js"><link rel="prefetch" href="/assets/js/37.3351af87.js"><link rel="prefetch" href="/assets/js/370.14439cd0.js"><link rel="prefetch" href="/assets/js/371.8f1680c9.js"><link rel="prefetch" href="/assets/js/372.61718293.js"><link rel="prefetch" href="/assets/js/373.4b4647e8.js"><link rel="prefetch" href="/assets/js/374.71d42042.js"><link rel="prefetch" href="/assets/js/375.e4d369f2.js"><link rel="prefetch" href="/assets/js/376.51cd667f.js"><link rel="prefetch" href="/assets/js/377.023da5c6.js"><link rel="prefetch" href="/assets/js/378.726a5f82.js"><link rel="prefetch" href="/assets/js/379.720646dc.js"><link rel="prefetch" href="/assets/js/38.2334aea2.js"><link rel="prefetch" href="/assets/js/380.4d823b98.js"><link rel="prefetch" href="/assets/js/381.bdcccbea.js"><link rel="prefetch" href="/assets/js/382.8cce8942.js"><link rel="prefetch" href="/assets/js/383.cb7d71d3.js"><link rel="prefetch" href="/assets/js/384.bf2af7c5.js"><link rel="prefetch" href="/assets/js/385.1cc639e2.js"><link rel="prefetch" href="/assets/js/386.684b64ab.js"><link rel="prefetch" href="/assets/js/387.e16f4a68.js"><link rel="prefetch" href="/assets/js/388.c9b30f3b.js"><link rel="prefetch" href="/assets/js/389.a8b0f99a.js"><link rel="prefetch" href="/assets/js/39.683bc07a.js"><link rel="prefetch" href="/assets/js/390.b43004ff.js"><link rel="prefetch" href="/assets/js/391.c316049a.js"><link rel="prefetch" href="/assets/js/392.2c559de6.js"><link rel="prefetch" href="/assets/js/393.3055fc0a.js"><link rel="prefetch" href="/assets/js/394.7585ce4c.js"><link rel="prefetch" href="/assets/js/395.6f04bac1.js"><link rel="prefetch" href="/assets/js/396.a6536f32.js"><link rel="prefetch" href="/assets/js/397.e9807e10.js"><link rel="prefetch" href="/assets/js/398.b89dcc8a.js"><link rel="prefetch" href="/assets/js/399.da459f94.js"><link rel="prefetch" href="/assets/js/4.47196852.js"><link rel="prefetch" href="/assets/js/40.f2d861cf.js"><link rel="prefetch" href="/assets/js/400.d8b3b5fd.js"><link rel="prefetch" href="/assets/js/401.4a5b409e.js"><link rel="prefetch" href="/assets/js/402.f2c8802d.js"><link rel="prefetch" href="/assets/js/403.bd98e777.js"><link rel="prefetch" href="/assets/js/404.d2dab4f7.js"><link rel="prefetch" href="/assets/js/405.f83ce379.js"><link rel="prefetch" href="/assets/js/406.69a91345.js"><link rel="prefetch" href="/assets/js/407.3bc1a860.js"><link rel="prefetch" href="/assets/js/408.8b88a93c.js"><link rel="prefetch" href="/assets/js/409.269ef2c9.js"><link rel="prefetch" href="/assets/js/41.79fbb067.js"><link rel="prefetch" href="/assets/js/410.40dc1b76.js"><link rel="prefetch" href="/assets/js/411.6679eea2.js"><link rel="prefetch" href="/assets/js/412.2cdd21ea.js"><link rel="prefetch" href="/assets/js/413.f5418356.js"><link rel="prefetch" href="/assets/js/414.ed9da9ad.js"><link rel="prefetch" href="/assets/js/415.4cd14246.js"><link rel="prefetch" href="/assets/js/416.cd80178b.js"><link rel="prefetch" href="/assets/js/417.d650a560.js"><link rel="prefetch" href="/assets/js/418.ad71cbc7.js"><link rel="prefetch" href="/assets/js/419.8e6c87c0.js"><link rel="prefetch" href="/assets/js/42.101ecd13.js"><link rel="prefetch" href="/assets/js/420.71ec69ad.js"><link rel="prefetch" href="/assets/js/421.91d6b7be.js"><link rel="prefetch" href="/assets/js/422.353f77c5.js"><link rel="prefetch" href="/assets/js/423.60ef06c0.js"><link rel="prefetch" href="/assets/js/424.2e57687c.js"><link rel="prefetch" href="/assets/js/425.9413632b.js"><link rel="prefetch" href="/assets/js/426.e1b29e8b.js"><link rel="prefetch" href="/assets/js/427.ed640a0c.js"><link rel="prefetch" href="/assets/js/428.90a9eecd.js"><link rel="prefetch" href="/assets/js/429.bcc51151.js"><link rel="prefetch" href="/assets/js/43.cf663bf1.js"><link rel="prefetch" href="/assets/js/430.d7a129bf.js"><link rel="prefetch" href="/assets/js/431.6f0b95f4.js"><link rel="prefetch" href="/assets/js/432.c9964a14.js"><link rel="prefetch" href="/assets/js/433.fb0bc3bb.js"><link rel="prefetch" href="/assets/js/434.cbb78303.js"><link rel="prefetch" href="/assets/js/435.7633d592.js"><link rel="prefetch" href="/assets/js/436.dd3d00e6.js"><link rel="prefetch" href="/assets/js/437.40a87461.js"><link rel="prefetch" href="/assets/js/438.640ceed6.js"><link rel="prefetch" href="/assets/js/439.4bc626d3.js"><link rel="prefetch" href="/assets/js/44.0e34047e.js"><link rel="prefetch" href="/assets/js/440.840fff96.js"><link rel="prefetch" href="/assets/js/441.e8e14977.js"><link rel="prefetch" href="/assets/js/442.0f0a17b6.js"><link rel="prefetch" href="/assets/js/443.44c2279e.js"><link rel="prefetch" href="/assets/js/444.6d775f58.js"><link rel="prefetch" href="/assets/js/445.dfec1767.js"><link rel="prefetch" href="/assets/js/446.8282b220.js"><link rel="prefetch" href="/assets/js/447.4b8f1a4c.js"><link rel="prefetch" href="/assets/js/448.03b53f95.js"><link rel="prefetch" href="/assets/js/449.39dea464.js"><link rel="prefetch" href="/assets/js/45.fa02a8c0.js"><link rel="prefetch" href="/assets/js/450.948c5957.js"><link rel="prefetch" href="/assets/js/451.b4e00223.js"><link rel="prefetch" href="/assets/js/452.634de921.js"><link rel="prefetch" href="/assets/js/453.957a3638.js"><link rel="prefetch" href="/assets/js/454.d410cf71.js"><link rel="prefetch" href="/assets/js/455.8c5a2163.js"><link rel="prefetch" href="/assets/js/456.877d611f.js"><link rel="prefetch" href="/assets/js/457.8b24b950.js"><link rel="prefetch" href="/assets/js/458.591d759d.js"><link rel="prefetch" href="/assets/js/459.e114c85b.js"><link rel="prefetch" href="/assets/js/46.3a265755.js"><link rel="prefetch" href="/assets/js/460.1a928144.js"><link rel="prefetch" href="/assets/js/461.2a0384d2.js"><link rel="prefetch" href="/assets/js/462.5c3649e2.js"><link rel="prefetch" href="/assets/js/463.4221227c.js"><link rel="prefetch" href="/assets/js/464.866ac902.js"><link rel="prefetch" href="/assets/js/465.05a96c32.js"><link rel="prefetch" href="/assets/js/466.3efed881.js"><link rel="prefetch" href="/assets/js/467.ddd524e5.js"><link rel="prefetch" href="/assets/js/468.9eebe3d9.js"><link rel="prefetch" href="/assets/js/469.281b53ec.js"><link rel="prefetch" href="/assets/js/47.2d120101.js"><link rel="prefetch" href="/assets/js/470.decda882.js"><link rel="prefetch" href="/assets/js/471.242be672.js"><link rel="prefetch" href="/assets/js/472.da4abae1.js"><link rel="prefetch" href="/assets/js/473.9d64ea3e.js"><link rel="prefetch" href="/assets/js/474.5362ec5b.js"><link rel="prefetch" href="/assets/js/475.6904e585.js"><link rel="prefetch" href="/assets/js/476.c460d90a.js"><link rel="prefetch" href="/assets/js/477.474813fa.js"><link rel="prefetch" href="/assets/js/478.d51e07b1.js"><link rel="prefetch" href="/assets/js/479.f0fa0689.js"><link rel="prefetch" href="/assets/js/48.57af7d42.js"><link rel="prefetch" href="/assets/js/480.8b194bbe.js"><link rel="prefetch" href="/assets/js/481.f2f1aeeb.js"><link rel="prefetch" href="/assets/js/482.6903e11b.js"><link rel="prefetch" href="/assets/js/483.65d04ad9.js"><link rel="prefetch" href="/assets/js/484.51e94629.js"><link rel="prefetch" href="/assets/js/485.415550f4.js"><link rel="prefetch" href="/assets/js/486.d24d0355.js"><link rel="prefetch" href="/assets/js/487.9eea1be6.js"><link rel="prefetch" href="/assets/js/488.eb3d4584.js"><link rel="prefetch" href="/assets/js/489.6f97c453.js"><link rel="prefetch" href="/assets/js/49.3de3d3a7.js"><link rel="prefetch" href="/assets/js/490.e83cd7f7.js"><link rel="prefetch" href="/assets/js/491.4a6acdf2.js"><link rel="prefetch" href="/assets/js/492.e0548c45.js"><link rel="prefetch" href="/assets/js/493.29b0d0b2.js"><link rel="prefetch" href="/assets/js/494.9f66922c.js"><link rel="prefetch" href="/assets/js/495.31a136ac.js"><link rel="prefetch" href="/assets/js/496.4c1f303f.js"><link rel="prefetch" href="/assets/js/497.b03e6c3f.js"><link rel="prefetch" href="/assets/js/498.a8178b3e.js"><link rel="prefetch" href="/assets/js/499.9f38526a.js"><link rel="prefetch" href="/assets/js/5.33db7f08.js"><link rel="prefetch" href="/assets/js/50.27055b53.js"><link rel="prefetch" href="/assets/js/500.262b9103.js"><link rel="prefetch" href="/assets/js/501.c97f4e75.js"><link rel="prefetch" href="/assets/js/502.5d5c5edd.js"><link rel="prefetch" href="/assets/js/503.62a2a01d.js"><link rel="prefetch" href="/assets/js/504.855415b5.js"><link rel="prefetch" href="/assets/js/505.79d4fddb.js"><link rel="prefetch" href="/assets/js/506.f2675378.js"><link rel="prefetch" href="/assets/js/507.7d811dcb.js"><link rel="prefetch" href="/assets/js/508.6c63d710.js"><link rel="prefetch" href="/assets/js/509.a6dbe871.js"><link rel="prefetch" href="/assets/js/51.82e12c0c.js"><link rel="prefetch" href="/assets/js/510.6ba536a4.js"><link rel="prefetch" href="/assets/js/511.47fcc7dd.js"><link rel="prefetch" href="/assets/js/512.f5b2b05c.js"><link rel="prefetch" href="/assets/js/513.d1a9a405.js"><link rel="prefetch" href="/assets/js/514.4768319a.js"><link rel="prefetch" href="/assets/js/515.4a7312b1.js"><link rel="prefetch" href="/assets/js/516.2a75898b.js"><link rel="prefetch" href="/assets/js/517.0734d077.js"><link rel="prefetch" href="/assets/js/518.a0affa56.js"><link rel="prefetch" href="/assets/js/519.3b143230.js"><link rel="prefetch" href="/assets/js/52.08471186.js"><link rel="prefetch" href="/assets/js/520.98088423.js"><link rel="prefetch" href="/assets/js/521.09d6f9e3.js"><link rel="prefetch" href="/assets/js/522.0a7f1cfd.js"><link rel="prefetch" href="/assets/js/523.460a682d.js"><link rel="prefetch" href="/assets/js/53.81c949e4.js"><link rel="prefetch" href="/assets/js/54.23834020.js"><link rel="prefetch" href="/assets/js/55.98bddbab.js"><link rel="prefetch" href="/assets/js/56.f33c89be.js"><link rel="prefetch" href="/assets/js/57.974b4102.js"><link rel="prefetch" href="/assets/js/58.e357e1b7.js"><link rel="prefetch" href="/assets/js/59.1cf2f460.js"><link rel="prefetch" href="/assets/js/6.d37d398a.js"><link rel="prefetch" href="/assets/js/60.bccde908.js"><link rel="prefetch" href="/assets/js/61.33679650.js"><link rel="prefetch" href="/assets/js/62.fe42a718.js"><link rel="prefetch" href="/assets/js/63.910cc28d.js"><link rel="prefetch" href="/assets/js/64.3a046b10.js"><link rel="prefetch" href="/assets/js/65.6bc58366.js"><link rel="prefetch" href="/assets/js/66.29ed3089.js"><link rel="prefetch" href="/assets/js/67.3a4a22d1.js"><link rel="prefetch" href="/assets/js/68.05fa411c.js"><link rel="prefetch" href="/assets/js/69.44dfc2db.js"><link rel="prefetch" href="/assets/js/7.8c733af6.js"><link rel="prefetch" href="/assets/js/70.059cdd51.js"><link rel="prefetch" href="/assets/js/71.d58561d2.js"><link rel="prefetch" href="/assets/js/72.056ba678.js"><link rel="prefetch" href="/assets/js/73.25916778.js"><link rel="prefetch" href="/assets/js/74.1f1823dc.js"><link rel="prefetch" href="/assets/js/75.2f5b0b73.js"><link rel="prefetch" href="/assets/js/76.06e76fe6.js"><link rel="prefetch" href="/assets/js/77.206d48bf.js"><link rel="prefetch" href="/assets/js/78.2f07e42d.js"><link rel="prefetch" href="/assets/js/79.994c527d.js"><link rel="prefetch" href="/assets/js/8.e8c4adeb.js"><link rel="prefetch" href="/assets/js/80.82c6c4f9.js"><link rel="prefetch" href="/assets/js/81.83bd28d9.js"><link rel="prefetch" href="/assets/js/82.7fbb77e1.js"><link rel="prefetch" href="/assets/js/83.e5773686.js"><link rel="prefetch" href="/assets/js/84.13db35cf.js"><link rel="prefetch" href="/assets/js/85.e6a2aa9d.js"><link rel="prefetch" href="/assets/js/86.715ac425.js"><link rel="prefetch" href="/assets/js/87.10b54644.js"><link rel="prefetch" href="/assets/js/88.477faa20.js"><link rel="prefetch" href="/assets/js/89.a562feda.js"><link rel="prefetch" href="/assets/js/9.635384b9.js"><link rel="prefetch" href="/assets/js/90.c7874d64.js"><link rel="prefetch" href="/assets/js/91.e61cbe07.js"><link rel="prefetch" href="/assets/js/92.45b11d5e.js"><link rel="prefetch" href="/assets/js/93.f587deb4.js"><link rel="prefetch" href="/assets/js/94.19940b43.js"><link rel="prefetch" href="/assets/js/95.d9763768.js"><link rel="prefetch" href="/assets/js/96.3ed0322b.js"><link rel="prefetch" href="/assets/js/97.d368e630.js"><link rel="prefetch" href="/assets/js/98.8b86b8af.js"><link rel="prefetch" href="/assets/js/99.53eb946a.js"><link rel="prefetch" href="/assets/js/vendors~docsearch.262891fb.js">
    <link rel="stylesheet" href="/assets/css/0.styles.679f71b6.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="/zh/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/GroupByFillQuery.html" class="nav-link">English</a></li><li class="dropdown-item"><!----> <a href="/zh/SystemDesign/DataQuery/GroupByFillQuery.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="/zh/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/GroupByFillQuery.html" class="nav-link">English</a></li><li class="dropdown-item"><!----> <a href="/zh/SystemDesign/DataQuery/GroupByFillQuery.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" class="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" aria-current="page" class="active 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="降采样补空值查询"><a href="#降采样补空值查询" class="header-anchor">#</a> 降采样补空值查询</h1> <p>GroupByFill 查询的主要逻辑在 <code>GroupByFillDataSet</code></p> <ul><li><code>org.apache.iotdb.db.query.dataset.groupby.GroupByFillDataSet</code></li></ul> <p>GroupByFill是对原降采样结果进行填充，目前仅支持使用前值填充的方式。</p> <ul><li>在Group By Fill中，Group by子句不支持滑动步长，否则抛异常</li> <li>Fill子句中仅能使用Previous和PREVIOUSUNTILLAST这两种插值方式，Linear不支持</li> <li>Previous和PREVIOUSUNTILLAST对fill的时间不做限制</li> <li>填充只针对last_value这一聚合函数，其他的函数不支持，如果其他函数的聚合值查询结果为null，依旧为null，不进行填充</li></ul> <h2 id="previousuntillast与previous填充的区别"><a href="#previousuntillast与previous填充的区别" class="header-anchor">#</a> PREVIOUSUNTILLAST与PREVIOUS填充的区别</h2> <p>Previous填充方式的语意没有变，只要前面有值，就可以拿过来填充；
PREVIOUSUNTILLAST考虑到在某些业务场景下，所填充的值的时间不能大于该时间序列last的时间戳（从业务角度考虑，取历史数据不能取未来历史数据）
看下面的例子，或许更容易理解</p> <p>A点时间戳为1，B为5，C为20，D为30，N为8，M为38</p> <p>原始数据为<img src="https://user-images.githubusercontent.com/16079446/78784824-9f41ae00-79d8-11ea-9920-0825e081cae0.png" style="width:100%;max-width:800px;max-height:600px;margin-left:auto;margin-right:auto;display:block;"></p> <p><code>select temperature FROM root.ln.wf01.wt01 where time &gt;= 1 and time &lt;= 38</code></p> <table><thead><tr><th>Time</th> <th>root.ln.wf01.wt01.temperature</th></tr></thead> <tbody><tr><td>1</td> <td>21</td></tr> <tr><td>3</td> <td>23</td></tr> <tr><td>5</td> <td>25</td></tr> <tr><td>20</td> <td>26</td></tr> <tr><td>27</td> <td>29</td></tr> <tr><td>28</td> <td>30</td></tr> <tr><td>30</td> <td>40</td></tr></tbody></table> <p>当我们使用Previous插值方式时，即使D到M这一段是未来的数据，我们也会用D点的数据进行填充</p> <p><code>SELECT last_value(temperature) as last_temperature FROM root.ln.wf01.wt01 GROUP BY([8, 39), 5m) FILL (int32[previous])</code></p> <table><thead><tr><th>Time</th> <th>last_temperature</th></tr></thead> <tbody><tr><td>8</td> <td>25</td></tr> <tr><td>13</td> <td>25</td></tr> <tr><td>18</td> <td>26</td></tr> <tr><td>23</td> <td>29</td></tr> <tr><td>28</td> <td>40</td></tr> <tr><td>33</td> <td>40</td></tr> <tr><td>38</td> <td>40</td></tr></tbody></table> <p>当我们使用NONLASTPREVIOUS插值方式时，因为D到M这一段是未来的数据，我们不会进行插值，还是返回null</p> <p><code>SELECT last_value(temperature) as last_temperature FROM root.ln.wf01.wt01 GROUP BY([8, 39), 5m) FILL (int32[PREVIOUSUNTILLAST])</code></p> <table><thead><tr><th>Time</th> <th>last_temperature</th></tr></thead> <tbody><tr><td>8</td> <td>25</td></tr> <tr><td>13</td> <td>25</td></tr> <tr><td>18</td> <td>26</td></tr> <tr><td>23</td> <td>29</td></tr> <tr><td>28</td> <td>40</td></tr> <tr><td>33</td> <td>null</td></tr> <tr><td>38</td> <td>null</td></tr></tbody></table> <h2 id="核心查询逻辑"><a href="#核心查询逻辑" class="header-anchor">#</a> 核心查询逻辑</h2> <p>在<code>GroupByFillDataSet</code>中维护了两个主要变量</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>// the first value for each time series
private Object[] previousValue;
// last timestamp for each time series
private long[] lastTimeArray;
</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></div></div><h3 id="previousvalue"><a href="#previousvalue" class="header-anchor">#</a> <code>previousValue</code></h3> <p><code>previousValue</code>这个变量维护了当前时间窗口的前一个降采样值，在<code>GroupByFillDataSet</code>构造函数中调用了<code>initPreviousParis</code>方法对其进行初始化。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>  private void initPreviousParis(QueryContext context, GroupByFillPlan groupByFillPlan)
          throws StorageEngineException, IOException, QueryProcessException {
    previousValue = new Object[paths.size()];
    for (int i = 0; i &lt; paths.size(); i++) {
      Path path = paths.get(i);
      TSDataType dataType = dataTypes.get(i);
      IFill fill = new PreviousFill(dataType, groupByEngineDataSet.getStartTime(), -1L);
      fill.constructReaders(path, groupByFillPlan.getAllMeasurementsInDevice(path.getDevice()), context);

      TimeValuePair timeValuePair = fill.getFillResult();
      if (timeValuePair == null || timeValuePair.getValue() == null) {
        previousValue[i] = null;
      } else {
        previousValue[i] = timeValuePair.getValue().getValue();
      }
    }
  }
</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></div></div><p><code>initPreviousParis</code>方法主要为每个时间序列构造了一个单点补空值查询，<code>queryTime</code>设置为降采样时间窗口的起始值，<code>beforeRange</code>不作限制。</p> <h3 id="lasttimearray"><a href="#lasttimearray" class="header-anchor">#</a> <code>lastTimeArray</code></h3> <p><code>lastTimeArray</code>这个变量维护了每个时间序列的最近时间戳值，主要用于<code>PREVIOUSUNTILLAST</code>这一填充方式，在<code>GroupByFillDataSet</code>构造函数中调用了<code>initLastTimeArray</code>方法对其进行初始化。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>  private void initLastTimeArray(QueryContext context)
      throws IOException, StorageEngineException, QueryProcessException {
    lastTimeArray = new long[paths.size()];
    Arrays.fill(lastTimeArray, Long.MAX_VALUE);
    for (int i = 0; i &lt; paths.size(); i++) {
      TimeValuePair lastTimeValuePair =
          LastQueryExecutor.calculateLastPairForOneSeries(paths.get(i), dataTypes.get(i), context);
      if (lastTimeValuePair.getValue() != null) {
        lastTimeArray[i] = lastTimeValuePair.getTimestamp();
      }
    }
  }
</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></div></div><p><code>initPreviousParis</code>方法主要为每个时间序列构造了一个最近时间戳 Last 查询</p> <h3 id="填充过程"><a href="#填充过程" class="header-anchor">#</a> 填充过程</h3> <p>填充过程在<code>nextWithoutConstraint</code>方法中完成，主要逻辑如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>protected RowRecord nextWithoutConstraint() throws IOException {

    // 首先通过groupByEngineDataSet，获得原始的降采样查询结果行
    RowRecord rowRecord = groupByEngineDataSet.nextWithoutConstraint();

    // 接下来对每个时间序列判断需不需要填充
    for (int i = 0; i &lt; paths.size(); i++) {
      Field field = rowRecord.getFields().get(i);
      // 当前值为null，需要进行填充
      if (field.getDataType() == null) {
        // 当前一个值不为null 并且 (填充方式不是PREVIOUSUNTILLAST 或者 当前时间小于改时间序列的最近时间戳)
        if (previousValue[i] != null
            &amp;&amp; (!((PreviousFill) fillTypes.get(dataTypes.get(i))).isUntilLast()
            || rowRecord.getTimestamp() &lt;= lastTimeArray[i])) {
          rowRecord.getFields().set(i, Field.getField(previousValue[i], dataTypes.get(i)));
        }
      } else {
        // 当前值不为null，不需要填充，用当前值更新previousValue数组
        previousValue[i] = field.getObjectValue(field.getDataType());
      }
    }
    return rowRecord;
  }
</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></div> <div class="page-nav"><p class="inner"><span class="prev">
        ←
        <a href="/zh/SystemDesign/DataQuery/FillFunction.html" class="prev">
          空值填充
        </a></span> <span class="next"><a href="/zh/SystemDesign/DataQuery/OrderByTimeQuery.html">
          按时间倒序查询
        </a>
        →
      </span></p></div> <p style="text-align: center;">Copyright © 2020 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.ee472f44.js" defer></script><script src="/assets/js/3.49f0f20a.js" defer></script><script src="/assets/js/289.8990a52d.js" defer></script>
  </body>
</html>