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  1. Core Server
  2. SERVER-8059

After movePrimary, db.getCollectionNames() excludes previously existing one-chunk collections

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      1. Create a sharded cluster (eg. two shards: A and B).
      2. Create a shardable database (eg. test).
      3. Create a sharded one-chunk, collection (eg. test.counter).
      4. Change the primary shard for the database (eg. A => B).
      5. db.getCollectionNames() should not include "test.counter".

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      1. Create a sharded cluster (eg. two shards: A and B). 2. Create a shardable database (eg. test). 3. Create a sharded one-chunk, collection (eg. test.counter). 4. Change the primary shard for the database (eg. A => B). 5. db.getCollectionNames() should not include "test.counter".

      db.getCollectionNames() on mongos essentially reflects db.getCollectionNames() output from the mongod of the database's primary shard. If small, one-chunk collections are created prior to a movePrimary, db.getCollectionNames() query the newly changed primary shard which doesn't report the existence of those small, one-chunk collections.

      mongos> sh.status()
--- Sharding Status --- 
  sharding version: { "_id" : 1, "version" : 3 }
  shards:
	{  "_id" : "s1",  "host" : "s1/localhost:10000,localhost:10001,localhost:10002",  "tags" : [ 	"a" ] }
	{  "_id" : "s2",  "host" : "s2/localhost:20000,localhost:20001,localhost:20002",  "tags" : [ 	"b" ] }
  databases:
	{  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
	{  "_id" : "test",  "partitioned" : true,  "primary" : "s2" }

mongos> db.counter.insert({a:1})
mongos> db.counter.ensureIndex({a:1})
mongos> sh.shardCollection("test.counter",{a:1})
{ "collectionsharded" : "test.counter", "ok" : 1 }
mongos> sh.status()
--- Sharding Status --- 
  sharding version: { "_id" : 1, "version" : 3 }
  shards:
	{  "_id" : "s1",  "host" : "s1/localhost:10000,localhost:10001,localhost:10002",  "tags" : [ 	"a" ] }
	{  "_id" : "s2",  "host" : "s2/localhost:20000,localhost:20001,localhost:20002",  "tags" : [ 	"b" ] }
  databases:
	{  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
	{  "_id" : "test",  "partitioned" : true,  "primary" : "s2" }
		test.counter chunks:
				s2	1
			{ "a" : { $minKey : 1 } } -->> { "a" : { $maxKey : 1 } } on : s2 Timestamp(1000, 0) 

mongos> db.getCollectionNames()
[ "counter", "system.indexes" ]
mongos> db.adminCommand({movePrimary:"test",to:"s1"})
{
	"primary " : "s1:s1/localhost:10000,localhost:10001,localhost:10002",
	"ok" : 1
}
mongos> db.getCollectionNames()
[ "system.indexes" ]
mongos> db.adminCommand({movePrimary:"test",to:"s2"})
{
	"primary " : "s2:s2/localhost:20000,localhost:20001,localhost:20002",
	"ok" : 1
}
mongos> db.getCollectionNames()
[ "counter", "system.indexes" ]

        1. move_primary.js
          3 kB

            Assignee:
            esha.maharishi@mongodb.com Esha Maharishi (Inactive)
            Reporter:
            stephen.lee Stephen Lee
            Votes:
            7 Vote for this issue
            Watchers:
            15 Start watching this issue

              Created:
              Updated:
              Resolved: