[SERVER-27356] Chunk is not marked as jumbo when it should Created: 09/Dec/16  Updated: 09/Dec/16  Resolved: 09/Dec/16

Status: Closed
Project: Core Server
Component/s: Sharding
Affects Version/s: 3.4.0
Fix Version/s: None

Type: Bug Priority: Major - P3
Reporter: Alexander Komyagin Assignee: Unassigned
Resolution: Duplicate Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Duplicate
duplicates SERVER-26531 jumbo flag in chunk can be cleared wh... Closed
Operating System: ALL
Participants:

 Description   

Sharded cluster with two shards.

Sharded collection 'test.test4' on {my_flag:1}, and then wrote many many docs with the same my_flag value. Then split the range manually to make sure that the big chunk is the lowest. According to the changelog and to the config server logs, the balancer has tried to move the chunk and failed:

3169:2016-12-08T15:01:06.681-0500 I SHARDING [Balancer] Performing a split because migration test.test4: [{ my_flag: MinKey }, { my_flag: 100.0 }), from rs1, to rs2 failed for size reasons :: caused by :: ChunkTooBig: Cannot move chunk: the maximum number of documents for a chunk is 133, the maximum chunk size is 67108864, average document size is 648943. Found 3001 documents in chunk  ns: test.test4 { my_flag: MinKey } -> { my_flag: 100.0 }
3170-2016-12-08T15:01:06.700-0500 I SHARDING [Balancer] Marking chunk ns: test.test4, shard: rs1, lastmod: 1|1||5849b98b0d4c5ace47a95847, min: { my_flag: MinKey }, max: { my_flag: 100.0 } as jumbo.
3171-2016-12-08T15:01:06.728-0500 I SHARDING [Balancer] about to log metadata event into actionlog: { _id: "AD-MAC10G.local-2016-12-08T15:01:06.728-0500-5849bc025079cb49a05d42aa", server: "AD-MAC10G.local", clientAddr: "", time: new Date(1481227266728), what: "balancer.round", ns: "", details: { executionTimeMillis: 296, errorOccured: false, candidateChunks: 1, chunksMoved: 1 } }

However, the chunk is not marked as jumbo as per mongoS:

mongos> db.chunks.find({ns:"test.test4"})
{ "_id" : "test.test4-my_flag_MinKey", "lastmod" : Timestamp(2, 1), "lastmodEpoch" : ObjectId("5849b98b0d4c5ace47a95847"), "ns" : "test.test4", "min" : { "my_flag" : { "$minKey" : 1 } }, "max" : { "my_flag" : 100 }, "shard" : "rs1" }
{ "_id" : "test.test4-my_flag_100.0", "lastmod" : Timestamp(2, 0), "lastmodEpoch" : ObjectId("5849b98b0d4c5ace47a95847"), "ns" : "test.test4", "min" : { "my_flag" : 100 }, "max" : { "my_flag" : 200 }, "shard" : "rs2" }
{ "_id" : "test.test4-my_flag_200.0", "lastmod" : Timestamp(1, 4), "lastmodEpoch" : ObjectId("5849b98b0d4c5ace47a95847"), "ns" : "test.test4", "min" : { "my_flag" : 200 }, "max" : { "my_flag" : { "$maxKey" : 1 } }, "shard" : "rs1" }


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