Percona is an open source database software, support, and services company that helps make databases and applications run better. We discussed one of

Configure HAProxy with PostgreSQL Using Built-in pgsql-check

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2024-05-14 06:30:04

Percona is an open source database software, support, and services company that helps make databases and applications run better.

We discussed one of the traditional ways to configure HAProxy with PostgreSQL in our previous blog about HAProxy using Xinetd. There we briefly mentioned the limitation of the HAProxy’s built-in pgsql-check health check option. It lacks features to detect and differentiate the Primary and Hot-Standby. It tries to establish a connection to the database instance and if the connection request is progressing, it will be considered as a successful check and there is no provision to check the current role (Primary or Standby).

Note: This blog demonstrates the concept. Integration with specific HA framework/script is left to users because there are a large number of HA solutions for PostgreSQL and these concepts are equally applicable for them

When a client initiates the connection to PostgreSQL, the first stage of a check is whether it is acceptable as per rules specified in pg_hba.conf. That stage needs to be completed before proceeding to the next stage of specific authentication mechanisms.