Write tickets during runtime are > 128

Description

This advisor warns if the number of write transactions (tickets) into the WiredTiger storage during runtime is more than 128.

This is relevant because the performance can drop if the number of write tickets is too high.

Ideally, the number of tickets should be based on the number of CPU available. The default number of write tickets is 128. You can adjust it for both your mongod and mongos nodes.

See wiredTigerConcurrentWriteTransactions in the MongoDB documentation.

This parameter also needs to be set at the configuration file.

Rule

db.adminCommand( { setParameter: 1, "wiredTigerConcurrentWriteTransactions": "128"  } ) 

Resolution

Adjust the number of write tickets allowed into the WiredTiger storage engine.

• Using the setParameter shell helper:

mongo> db.adminCommand( { setParameter: 1, "wiredTigerConcurrentWriteTransactions": "128"  } )

• Editing the configuration file

setParameter:     
   wiredTigerConcurrentWriteTransactions: 128

Note that the changes in the configuration file will take effect only after the server restart.

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