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Type: Bug
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Resolution: Duplicate
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Priority: Major - P3
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None
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Affects Version/s: None
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Component/s: None
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Catalog and Routing
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ALL
On master, the dropIndexes suppresses writeConcern errors.
Successful execution of the dropIndexes command:
1 { 2 "nIndexesWas" : 2, 3 "ok" : 1, 4 "raw" : { 5 "mongos_noop_writes_wait_for_write_concern-rs0/ip-10-122-1-7:20043,ip-10-122-1-7:20044,ip-10-122-1-7:20045" : { 6 "nIndexesWas" : 2, 7 "ok" : 1 8 } 9 }, 10 "$clusterTime" : { 11 "clusterTime" : Timestamp(1731848532, 1), 12 "signature" : { 13 "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), 14 "keyId" : NumberLong(0) 15 } 16 }, 17 "operationTime" : Timestamp(1731848532, 1) 18 }
Note the writeConcern error in case of a successful execution of createIndexes:
1 { 2 "numIndexesBefore" : 1, 3 "numIndexesAfter" : 2, 4 "createdCollectionAutomatically" : false, 5 "commitQuorum" : "majority", 6 "writeConcernError" : { 7 "code" : 64, 8 "codeName" : "WriteConcernFailed", 9 "errmsg" : "waiting for replication timed out", 10 "errInfo" : { 11 "wtimeout" : true, 12 "writeConcern" : { 13 "w" : 3, 14 "wtimeout" : 1000, 15 "provenance" : "clientSupplied" 16 } 17 } 18 },
In v5.0, on retrying a dropIndexes command (due to some transient error), write concern errors may be suppressed by a write error such as "IndexNotFound", and a user may mistakenly believe that the dropIndexes command was executed successfully on a majority of nodes; when in fact this dropIndexes action can be rolled back.
The response on running a dropIndexes command in v5.0 contains the wCE when the index is first dropped:
1 { 2 "raw" : { 3 "mongos_noop_writes_wait_for_write_concern-rs0/ip-10-122-1-7:20020,ip-10-122-1-7:20021,ip-10-122-1-7:20022" : { 4 "nIndexesWas" : 2, 5 "writeConcernError" : { 6 "code" : 64, 7 "codeName" : "WriteConcernFailed", 8 "errmsg" : "waiting for replication timed out", 9 "errInfo" : { 10 "wtimeout" : true, 11 "writeConcern" : { 12 "w" : 3, 13 "wtimeout" : 1000, 14 "provenance" : "clientSupplied" 15 } 16 } 17 }, 18 "ok" : 1 19 } 20 },
On retrying the dropIndexes command:
1 { 2 "raw" : { 3 "mongos_noop_writes_wait_for_write_concern-rs0/ip-10-122-1-7:20020,ip-10-122-1-7:20021,ip-10-122-1-7:20022" : { 4 "ok" : 0, 5 "errmsg" : "can't find index with key: { a: 1.0 }", 6 "code" : 27, 7 "codeName" : "IndexNotFound" 8 } 9 }, 10 "code" : 27, 11 "codeName" : "IndexNotFound", 12 "ok" : 0, 13 "errmsg" : "can't find index with key: { a: 1.0 }", 14 "$clusterTime" : { 15 "clusterTime" : Timestamp(1731597701, 1), 16 "signature" : { 17 "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), 18 "keyId" : NumberLong(0) 19 } 20 }, 21 "operationTime" : Timestamp(1731597701, 1) 22 }
Response when a createIndexes command (contains the wCE) is retried:
{ 2 "raw" : { 3 "mongos_noop_writes_wait_for_write_concern-rs0/ip-10-122-1-7:20020,ip-10-122-1-7:20021,ip-10-122-1-7:20022" : { 4 "numIndexesBefore" : 2, 5 "numIndexesAfter" : 2, 6 "note" : "all indexes already exist", 7 "writeConcernError" : { 8 "code" : 64, 9 "codeName" : "WriteConcernFailed", 10 "errmsg" : "waiting for replication timed out", 11 "errInfo" : { 12 "wtimeout" : true, 13 "writeConcern" : { 14 "w" : 3, 15 "wtimeout" : 1000, 16 "provenance" : "clientSupplied" 17 } 18 } 19 }, 20 "ok" : 1 21 } 22 }, 23 "writeConcernError" : { 24 "code" : 64, 25 "codeName" : "WriteConcernFailed", 26 "errmsg" : "waiting for replication timed out; Error details: { wtimeout: true, writeConcern: { w: 3, wtimeout: 1000, provenance: \"clientSupplied\" } } at mongos_noop_wri tes_wait_for_write_concern-rs0", 27 "errInfo" : { 28 "wtimeout" : true, 29 "writeConcern" : { 30 "w" : 3, 31 "wtimeout" : 1000, 32 "provenance" : "clientSupplied" 33 } 34 } 35 }, 36 "ok" : 1, 37 "$clusterTime" : { 38 "clusterTime" : Timestamp(1731597700, 6), 39 "signature" : { 40 "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), 41 "keyId" : NumberLong(0) 42 } 43 }, 44 "operationTime" : Timestamp(1731597700, 6) 45 }
- duplicates
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SERVER-97754 User-provided write concern is not honored for DDL operations on sharded clusters (always w:majority)
- Needs Scheduling
- related to
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SERVER-90152 dropIndex() should be idempotent
- Blocked
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SERVER-66811 mongos successfully drops indexes with unsatisfiable write concern
- Closed
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SERVER-80103 Mongos WriteConcernError Behavior Differs from Mongod
- Closed