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Type:
Bug
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Resolution: Duplicate
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Priority:
Critical - P2
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None
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Affects Version/s: 3.2.10, 3.4.2
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Component/s: Sharding
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None
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ALL
System information
PHP 7.0.15-1+deb.sury.org~trusty+1 (cli) (built: Jan 20 2017 09:16:11) ( NTS )
Copyright (c) 1997-2017 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2017 Zend Technologies
with Zend OPcache v7.0.15-1+deb.sury.org~trusty+1, Copyright (c) 1999-2017, by Zend Technologies
pecl mongodb 1.2.5
mongodb 3.4.2
Ubuntu 14.04.5
Linux 3.13.0-100-generic #147-Ubuntu SMP Tue Oct 18 16:48:51 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
We run a cluster with 27 shards and each application uses a local mongos to connect to it. We have the balancer stopped.
We often see Exception for querys to collections which are sharded. Everytime there is a change to shard version of the collection, our PHP clients report an error on a simple find operation. Sofar we have never seen an exception for our non PHP clients.
It seems that this issue was introduced with mongodb version 3.2.x, but we can also reproduce it on 3.4.2 in our dev environment.
To reproduce it in our dev environemnt I started to shard a collection, but I could also move a chunk or split a chunk. I choose this collection because we see problems for querys to this collection in production which runs version 3.2.10 and we hadn't sharded it in our dev environment so far (very small in dev).
There are no errors in router.log
Before we sharded the collection our PHP application showed no errors.
After sharding our PHP client reports:
[data.items] shard version not ok: version epoch mismatch detected for data.items, the collection may have been dropped and recreated ( ns : data.items, received : 0|0||000000000000000000000000, wanted : 1|0||58a46d88be4b4925a7638e2f, send ) /path/to/code/vendor/php/mongodb/Find.php (206) MongoDB\Driver\Server::executeQuery
Stacktrace:
[23] File: /path/to/code/src/model/dfp/connectors/mdb/MdbLineItemConnector.php in line 68 Method: rg\ODM\MongoDB\Cursor->toArray [24] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/rg/ODM/MongoDB/Cursor.php in line 277 Method: Doctrine\MongoDB\Cursor->toArray Parameter: [true] [25] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/Doctrine/MongoDB/Cursor.php in line 629 Method: Doctrine\MongoDB\Cursor->retry Parameter: [Closure, true] [26] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/Doctrine/MongoDB/Cursor.php in line 666 Method: Doctrine\MongoDB\Cursor->Doctrine\MongoDB\{closure} [27] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/Doctrine/MongoDB/Cursor.php in line 628 Parameter: [rg\core\base\objectManagers\mongodb\LoggingCursor] [28] Method: rg\core\base\objectManagers\mongodb\LoggingCursor->rewind [29] File: /path/to/code/src/core/base/objectManagers/mongodb/LoggingCursor.php in line 253 Method: Doctrine\MongoDB\Cursor->rewind [30] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/Doctrine/MongoDB/Cursor.php in line 490 Method: Doctrine\MongoDB\Cursor->retry Parameter: [Closure, false] [31] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/Doctrine/MongoDB/Cursor.php in line 666 Method: Doctrine\MongoDB\Cursor->Doctrine\MongoDB\{closure} [32] File: /path/to/code/vendor/composer/rg/mongodb-odm-light/lib/Doctrine/MongoDB/Cursor.php in line 489 Method: Alcaeus\MongoDbAdapter\AbstractCursor->rewind [33] File: /path/to/code/vendor/composer/alcaeus/mongo-php-adapter/lib/Alcaeus/MongoDbAdapter/AbstractCursor.php in line 190 Method: Alcaeus\MongoDbAdapter\AbstractCursor->ensureIterator [34] File: /path/to/code/vendor/composer/alcaeus/mongo-php-adapter/lib/Alcaeus/MongoDbAdapter/AbstractCursor.php in line 297 Method: MongoCursor->ensureCursor [35] File: /path/to/code/vendor/composer/alcaeus/mongo-php-adapter/lib/Mongo/MongoCursor.php in line 443 Method: MongoCursor->doQuery [36] File: /path/to/code/vendor/composer/alcaeus/mongo-php-adapter/lib/Mongo/MongoCursor.php in line 166 Method: MongoDB\Collection->find Parameter: [MongoDB\Model\BSONDocument: ['o' => MongoDB\Model\BSONDocument: ['$in' => ['0' => 123456, '1' => 275383959000, '2' => 114204279, '3' => 233433999, '4' => 233014719, '5' => 237809079, '6' => 247189479, '7' => 251772159, '8' => 260437839, '9' => 275383959, '10' => 285140199, [10more ...]]], '$comment' => 'cId f8688c0e3b4b6de7b86d0c38569fb290,vId 165...'], ['batchSize' => 0, 'modifiers' => [], 'projection' => [], 'readPreference' => MongoDB\Driver\ReadPreference, 'readConcern' => MongoDB\Driver\ReadConcern, 'typeMap' => ['array' => 'MongoDB\Model\BSONArray', 'document' => 'MongoDB\Model\BSONDocument', 'root' => 'MongoDB\Model\BSONDocument']]] [37] File: /path/to/code/vendor/composer/mongodb/mongodb/src/Collection.php in line 525 Method: MongoDB\Operation\Find->execute Parameter: [MongoDB\Driver\Server: [MongoDB\Driver\Server Object ( [host] => localhost [port] => 27017 [type] => 2 [is_primary] => [is_secondary] => [is_arbiter] => [is_hidden] => [is_passive] => [last_is_master] => Array ( [ismaster] => 1 [msg] => isdbgrid [maxBsonObjectSize] => 16777216 [maxMessageSizeBytes] => 48000000 [maxWriteBatchSize] => 1000 [localTime] => MongoDB\BSON\UTCDateTime Object ( [milliseconds] => 1487171166812 ) [maxWireVersion] => 5 [minWireVersion] => 0 [ok] => 1 ) [round_trip_time] => 0 ) ]] [38] File: /path/to/code/vendor/php/mongodb/Find.php in line 206 Method: MongoDB\Driver\Server->executeQuery Parameter: ['data.items', MongoDB\Driver\Query, MongoDB\Driver\ReadPreference]
To fix the router reporting this exception on a query we found 3 ways:
- restart router
- flushRouterConfig
- do a find query on this collection via mongo shell. (tested with version 3.4.2 only)
Could it be that routers only trigger chunk information updates when a client does an operation on a collection? -> this is broken for php driver only?
Since we can reproduce it in our dev environment with version 3.4.2, we our glad to debug this with your help.
This is a blocker for us in production since even the balancer is off, autosplits also cause this issue.
- duplicates
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- Closed
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- links to