Mesclar grupos em um cluster fragmentado
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Visão geral
O comando mergeChunks permite combinar chunks contínuos no mesmo shard em um único chunk. Este tutorial explica como mesclar chunks vizinhos em um cluster fragmentado.
Procedimento
Observação
Os exemplos deste procedimento usam uma collection members no reconhecimento de data center dados test , usando o campo username como a chave de fragmento.
Identificar intervalos de blocos
Em mongosh, identifique as faixas de chunks com a seguinte operação:
sh.status()
Na saída, os intervalos de parte aparecem após as contagens de parte para cada collection fragmentada, como no exemplo a seguir:
--- Sharding Status --- sharding version: { "_id" : 1, "minCompatibleVersion" : 5, "currentVersion" : 6, "clusterId" : ObjectId("5ebf0bfd3eeb6037ec7cbba9") } shards: { "_id" : "shardA", "host" : "shardA/shardA-m1.example.net:27018,shardA-m2.example.net:27018,shardA-m3.example.net:27018", "state" : 1 } { "_id" : "shardB", "host" : "shardB/shardB-m1.example.net:27018,shardB-m2.example.net:27018,shardB-m3.example.net:27018", "state" : 1 } active mongoses: "4.4.0" : 1 autosplit: Currently enabled: yes balancer: Currently enabled: yes Currently running: no Failed balancer rounds in last 5 attempts: 0 Migration Results for the last 24 hours: 519 : Success databases: { "_id" : "config", "primary" : "config" } config.system.sessions shard key: { "_id" : 1 } unique: false balancing: true chunks: shardA 512 shardB 512 too many chunks to print, use verbose if you want to force print { "_id" : "test", "primary" : "shardA", "version" : { "uuid" : UUID("22c042fc-7e3d-4c6d-992d-f3d714759781"), "lastMod" : 1 } } test.members shard key: { "username" : 1 } unique: false balancing: true chunks: shardA 7 shardB 7 { "username" : { "$minKey" : 1 } } -->> { "username" : "user16643" } on : shardB Timestamp(13, 0) { "username" : "user16643" } -->> { "username" : "user2329" } on : shardB Timestamp(16, 0) { "username" : "user2329" } -->> { "username" : "user29937" } on : shardB Timestamp(17, 0) { "username" : "user29937" } -->> { "username" : "user36583" } on : shardB Timestamp(18, 0) { "username" : "user36583" } -->> { "username" : "user43229" } on : shardB Timestamp(19, 0) { "username" : "user43229" } -->> { "username" : "user49877" } on : shardB Timestamp(20, 0) { "username" : "user49877" } -->> { "username" : "user56522" } on : shardB Timestamp(21, 0) { "username" : "user56522" } -->> { "username" : "user63169" } on : shardA Timestamp(21, 1) { "username" : "user63169" } -->> { "username" : "user69816" } on : shardA Timestamp(10, 1) { "username" : "user69816" } -->> { "username" : "user76462" } on : shardA Timestamp(11, 1) { "username" : "user76462" } -->> { "username" : "user83108" } on : shardA Timestamp(12, 1) { "username" : "user83108" } -->> { "username" : "user89756" } on : shardA Timestamp(14, 1) { "username" : "user89756" } -->> { "username" : "user96401" } on : shardA Timestamp(15, 1) { "username" : "user96401" } -->> { "username" : { "$maxKey" : 1 } } on : shardA Timestamp(15, 2)
Os intervalos de parte aparecem após as contagens de parte para cada collection fragmentada. Por exemplo, a seguir estão as partes para a collection test.members :
{ "username" : { "$minKey" : 1 } } -->> { "username" : "user16643" } on : shardB Timestamp(13, 0) { "username" : "user16643" } -->> { "username" : "user2329" } on : shardB Timestamp(16, 0) { "username" : "user2329" } -->> { "username" : "user29937" } on : shardB Timestamp(17, 0) { "username" : "user29937" } -->> { "username" : "user36583" } on : shardB Timestamp(18, 0) { "username" : "user36583" } -->> { "username" : "user43229" } on : shardB Timestamp(19, 0) { "username" : "user43229" } -->> { "username" : "user49877" } on : shardB Timestamp(20, 0) { "username" : "user49877" } -->> { "username" : "user56522" } on : shardB Timestamp(21, 0) { "username" : "user56522" } -->> { "username" : "user63169" } on : shardA Timestamp(21, 1) { "username" : "user63169" } -->> { "username" : "user69816" } on : shardA Timestamp(10, 1) { "username" : "user69816" } -->> { "username" : "user76462" } on : shardA Timestamp(11, 1) { "username" : "user76462" } -->> { "username" : "user83108" } on : shardA Timestamp(12, 1) { "username" : "user83108" } -->> { "username" : "user89756" } on : shardA Timestamp(14, 1) { "username" : "user89756" } -->> { "username" : "user96401" } on : shardA Timestamp(15, 1) { "username" : "user96401" } -->> { "username" : { "$maxKey" : 1 } } on : shardA Timestamp(15, 2)
Mesclar parte
Mesclar chunks contíguos no mesmo fragmento.
Por exemplo, considere os seguintes intervalos de chunks no shardA :
Observação
As partes a serem mescladas estão em destaque.
{ "username" : "user56522" } -->> { "username" : "user63169" } on : shardA Timestamp(21, 1) { "username" : "user63169" } -->> { "username" : "user69816" } on : shardA Timestamp(10, 1) { "username" : "user69816" } -->> { "username" : "user76462" } on : shardA Timestamp(11, 1) { "username" : "user76462" } -->> { "username" : "user83108" } on : shardA Timestamp(12, 1) { "username" : "user83108" } -->> { "username" : "user89756" } on : shardA Timestamp(14, 1) { "username" : "user89756" } -->> { "username" : "user96401" } on : shardA Timestamp(15, 1) { "username" : "user96401" } -->> { "username" : { "$maxKey" : 1 } } on : shardA Timestamp(15, 2)
Para mesclar a parte contígua destacada, emita o comando { mergeChunks admin no reconhecimento de data center :
db.adminCommand( { mergeChunks: "test.members", bounds: [ { "username" : "user69816" }, { "username" : "user96401" } ] } )
Em caso de sucesso, mergeChunks produz o seguinte resultado:
{ "ok" : 1, "operationTime" : Timestamp(1589580356, 14), "$clusterTime" : { "clusterTime" : Timestamp(1589580356, 14), "signature" : { "hash" : BinData(0,"up5VKd49G/uPCq1iger2nOtfIHw="), "keyId" : NumberLong("6827188741371592725") } } }
Em qualquer condição de falha, o mergeChunks retorna um documento onde o valor do campo ok é 0 .
Visualizar intervalos de parte mesclados
Após mesclar as partes identificadas, confirme a nova parte da seguinte maneira:
sh.status()
A saída de sh.status() deve ser semelhante:
--- Sharding Status --- sharding version: { "_id" : 1, "minCompatibleVersion" : 5, "currentVersion" : 6, "clusterId" : ObjectId("5ebef5447fa151d4bd79dd72") } shards: { "_id" : "shardA", "host" : "shardA/shardA-m1.example.net:27018,shardA-m2.example.net:27018,shardA-m3.example.net:27018", "state" : 1 } { "_id" : "shardB", "host" : "shardB/shardB-m1.example.net:27018,shardB-m2.example.net:27018,shardB-m3.example.net:27018", "state" : 1 } active mongoses: "4.4.0" : 1 autosplit: Currently enabled: yes balancer: Currently enabled: yes Currently running: no Failed balancer rounds in last 5 attempts: 0 Migration Results for the last 24 hours: 519 : Success databases: { "_id" : "config", "primary" : "config" } config.system.sessions shard key: { "_id" : 1 } unique: false balancing: true chunks: shardA 512 shardB 512 too many chunks to print, use verbose if you want to force print { "_id" : "test", "primary" : "shardA", "version" : { "uuid" : UUID("22c042fc-7e3d-4c6d-992d-f3d714759781"), "lastMod" : 1 } } test.members shard key: { "username" : 1 } unique: false balancing: true chunks: shardA 5 shardB 6 { "username" : { "$minKey" : 1 } } -->> { "username" : "user16643" } on : shardA Timestamp(22, 0) { "username" : "user16643" } -->> { "username" : "user2329" } on : shardB Timestamp(22, 1) { "username" : "user2329" } -->> { "username" : "user29937" } on : shardB Timestamp(17, 0) { "username" : "user29937" } -->> { "username" : "user36583" } on : shardB Timestamp(18, 0) { "username" : "user36583" } -->> { "username" : "user43229" } on : shardB Timestamp(19, 0) { "username" : "user43229" } -->> { "username" : "user49877" } on : shardB Timestamp(20, 0) { "username" : "user49877" } -->> { "username" : "user56522" } on : shardB Timestamp(21, 0) { "username" : "user56522" } -->> { "username" : "user63169" } on : shardA Timestamp(21, 1) { "username" : "user63169" } -->> { "username" : "user69816" } on : shardA Timestamp(10, 1) { "username" : "user69816" } -->> { "username" : "user96401" } on : shardA Timestamp(21, 2) { "username" : "user96401" } -->> { "username" : { "$maxKey" : 1 } } on : shardA Timestamp(15, 2)
Após a mesclagem, o balanceador pode migrar blocos entre fragmentos para garantir uma distribuição mais uniforme de blocos.