mongodb常用命令整理

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慢查询相关

慢查询

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db.currentOp().inprog.forEach(
  function(op) {
    if(op.secs_running > 5) printjson(op);
  }
)

db.killOp(opid) // kill op

返回参数详解

wiredtiger相关

查看mongodb cache size(bytes)

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db.runCommand( { serverStatus: 1 } ).wiredTiger.cache["bytes currently in the cache"]

查看mongodb内存占用(MB)

mongo shell

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db.runCommand( { serverStatus: 1, workingSet: 1 } ).mem.resident

linux shell(最后一列是实际物理内存占用)

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ps -e -o 'pid,comm,rsz'

查看系统缺页信息

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ps -eo min_flt,maj_flt,pid,%cpu,%mem,pagein,args  --sort=min_flt | grep mongo

数据chunk相关

查看chunk大小

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var ns = "test.test"
var key = {account:1} 

db.getSiblingDB("config").chunks.find({ns : ns}).forEach(function(chunk) {
        var ds = db.getSiblingDB(ns.split(".")[0]).runCommand({datasize:chunk.ns,keyPattern:key,min:chunk.min,max:chunk.max});
        print("Chunk: "+chunk._id +" has a size of "+ds.size+", and includes "+ds.numObjects+" objects (took "+ds.millis+"ms)")
    }
)

查询并切分大chunk

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sh.stopBalancer()

use config
db.chunks.find({"ns": "test.user", jumbo: true})

sh.splitAt("db.collection", { account: "shardkey" })

sh.splitFind("db.collection", { account: "shardkey" })

sh.moveChunk("db.collection", { shardkey:"shardkey所在的块" }, "需要移动的目标分片ID")

sh.startBalancer()

Balancer

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use config
db.settings.update(
  { _id: "balancer" },
  { $set: { activeWindow : { start: "23:00", stop: "6:00" } } },
  { upsert: true }

)

数据库迁移

js + shell

迁移脚本