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I'm having trouble finding a good summary of the advantages/disadvantages of using pgbouncer for transaction pooling vs session pooling.

Does it mean that a transaction heavy workload is somehow better load balanced? Is it to prevent as many connections being required to connect from pgbouncer to the database?

dlamotte
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1 Answers1

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Transaction-level pooling will help if you have apps that hold idle sessions. PgBouncer won't need to keep sessions open and idle, it just grabs one when a new transaction is started. Those idle sessions only cost you a pgbouncer connection, not a real idle Pg session with a backend sitting around wasting memory & synchronisation overhead doing nothing.

The main reason you'd want session pooling instead of transaction pooling is if you want to use named prepared statements, advisory locks, listen/notify, or other features that operate on a session level not a transaction level.

Craig Ringer
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