MongoDB集群分片管理之哈希分片

原创

那海蓝蓝 2021-04-19 11:33:16 博主文章分类：MongoDB ©著作权

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检查数据库分片

mongos> use config
switched to db config
mongos> db.databases.find()
{ "_id" : "recommend", "primary" : "hdshard1", "partitioned" : true, "version" : { "uuid" : UUID("cb833b8e-cc4f-4c52-83c3-719aa383bac4"), "lastMod" : 1 } }
{ "_id" : "db1", "primary" : "hdshard3", "partitioned" : true, "version" : { "uuid" : UUID("71bb472c-7896-4a31-a77c-e3aaf723be3c"), "lastMod" : 1 } }

可以看到数据库分片已经打开。

查看集合分片情况

mongos> db.rcmd_1_min_tag_mei_rong.getShardDistribution()
Collection recommend.rcmd_1_min_tag_mei_rong is not sharded.

接下来我们对该集合进行分片。

查看索引

mongos> db.rcmd_1_min_tag_mei_rong.getIndexes()
[
	{
		"v" : 2,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "recommend.rcmd_1_min_tag_mei_rong"
	}
]

创建哈希索引

mongos> db.rcmd_1_min_tag_mei_rong.createIndex({_id:'hashed'})
{
	"raw" : {
		"hdshard1/172.16.254.136:40001,172.16.254.137:40001,172.16.254.138:40001" : {
			"createdCollectionAutomatically" : false,
			"numIndexesBefore" : 1,
			"numIndexesAfter" : 2,
			"ok" : 1
		}
	},
	"ok" : 1,
	"operationTime" : Timestamp(1618801258, 1),
	"$clusterTime" : {
		"clusterTime" : Timestamp(1618801258, 1),
		"signature" : {
			"hash" : BinData(0,"Ls7hIrcqTdWwfI49kxXo6NQtAk4="),
			"keyId" : NumberLong("6941260985399246879")
		}
	}
}

检查索引

mongos> db.rcmd_1_min_tag_mei_rong.getIndexes()
[
	{
		"v" : 2,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "recommend.rcmd_1_min_tag_mei_rong"
	},
	{
		"v" : 2,
		"key" : {
			"_id" : "hashed"
		},
		"name" : "_id_hashed",
		"ns" : "recommend.rcmd_1_min_tag_mei_rong"
	}
]

可以看到id字段的哈希索引已经创建。

进行哈希分片

mongos> sh.shardCollection( "recommend.rcmd_1_min_tag_mei_rong", { _id: "hashed" } )
{
	"collectionsharded" : "recommend.rcmd_1_min_tag_mei_rong",
	"collectionUUID" : UUID("ccac34f4-59e4-4048-971b-644b454adc13"),
	"ok" : 1,
	"operationTime" : Timestamp(1618801293, 5),
	"$clusterTime" : {
		"clusterTime" : Timestamp(1618801293, 5),
		"signature" : {
			"hash" : BinData(0,"bs4MPk31IZlYGMw3c2JN6eJ3pSc="),
			"keyId" : NumberLong("6941260985399246879")
		}
	}
}

查看分片情况

mongos> db.rcmd_1_min_tag_mei_rong.getShardDistribution()

Shard hdshard1 at hdshard1/172.16.254.136:40001,172.16.254.137:40001,172.16.254.138:40001
 data : 72.94MiB docs : 166775 chunks : 3
 estimated data per chunk : 24.31MiB
 estimated docs per chunk : 55591

Shard hdshard2 at hdshard2/172.16.254.136:40002,172.16.254.137:40002,172.16.254.138:40002
 data : 96.13MiB docs : 219788 chunks : 3
 estimated data per chunk : 32.04MiB
 estimated docs per chunk : 73262

Shard hdshard3 at hdshard3/172.16.254.136:40003,172.16.254.137:40003,172.16.254.138:40003
 data : 64.11MiB docs : 146526 chunks : 2
 estimated data per chunk : 32.05MiB
 estimated docs per chunk : 73263

Totals
 data : 233.18MiB docs : 533089 chunks : 8
 Shard hdshard1 contains 31.27% data, 31.28% docs in cluster, avg obj size on shard : 458B
 Shard hdshard2 contains 41.22% data, 41.22% docs in cluster, avg obj size on shard : 458B
 Shard hdshard3 contains 27.49% data, 27.48% docs in cluster, avg obj size on shard : 458B

哈希分片已经完成。