MongoDB read ticket is more than 128

Description

This advisor warns if the number of concurrent read transactions (tickets) into the WiredTiger storage is more than 128. If the number is too high, this can cause performance issues.

Ideally, the number of read tickets should be based on the number of CPU available.

The default number of read tickets is 128. You can adjust it for both your mongod and mongos nodes.

For more information, see wiredTigerConcurrentReadTransactions in the MongoDB documentation.

Rule

MONGODB_GETPARAMETER

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

Resolution

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

• Using the setParameter shell helper:

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

• Editing the configuration file:

setParameter:
   wiredTigerConcurrentReadTransactions: 256

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

Need more support from Percona?

Percona experts bring years of experience in tackling tough database performance issues and design challenges.