Connection pooling

• A pattern used with storing already precreated connections to a db, which can be used when talking to a database instead of connecting anew to a database.

• Similar to the pattern of object pooling

Benefits

• speed, faster to use already created connections rather than alway creating new connections

Libraries

• Java

  • HikariCP

  • C3po

Improving

• More threads only perform better when blocking creates opportunities for executing.

  • As blocking because of waiting for IO to execute (thus more threads is better for old HDD rather than SSD)

• More threads than CPUs means context switching, due to time slicing, is slower than one thread per cpu

• You want a small pool, saturated with threads waiting for connections.

• https://github.com/brettwooldridge/HikariCP/wiki/About-Pool-Sizing