• MongoDb
• Performance

MongoDb/Performance

• MongoDB-Performance-Best-Practices.pdf https://neotan.github.io/images/media/MongoDB-Performance-Best-Practices.pdf

Indicate in connection string to not use primary server in cluster

• mongodb://user:pass@urls/db?readPreference=secondary&readPreferenceTags=nodeType:ANALYTICS&readConcernLevel=local

Slow / Long running queries

• * $ mongo 10.32.2.4 --authenticationDatabase admin --username test --password mypass

• > db.currentOp()

• > db.currentOp({"secs_running": {$gte: 3}})

• Count documents in <db> <collection>

  • use <db>;

  • db.<collection>.count()

• DB locks

  • > db.serverStatus().globalLock

  • > db.serverStatus().locks

• DB version , want > 3.2 wiretiger document level locking

  • > db.version()

• DB memory usage should be less than ram

  • > db.serverStatus().mem

  • > db.serverStatus().wiredTiger.cache

• Check number of connections
  • db.serverStatus().connections
• Check indexs on a collection

  • db.<collection>.getIndexes()