High Performance PostgreSQL for Rails: users count inconsistency (page 56)

Hi @BraisonCrece. Thanks for posting this. The statement_timeout is used to set the max allowed time for operations to run before they’re cancelled.

What we need to do there is raise the statement_timeout to allow for more time. We can do that in several ways: by modifying the user’s persistent value, by modifying it within a psql session, or modifying it only for the scope of a single transaction. If you used the Rideshare scripts to create the owner or app_user users, you could modify them with a statement like this one:

ALTER ROLE owner SET statement_timeout = '60s';

That would raise the statement timeout to 60 seconds on an ongoing basis. You may need to raise it even more. You can also set it back later if you’d like.

You can also raise the statement timeout within a session:

SET statement_timeout = '60s';

Or you can scope the change to an individual transaction using the LOCAL keyword. To do that, use SET LOCAL as follows:

SET LOCAL statement_timeout = '60s';

With the bigger row count table where operations are taking longer, try raising the statement timeout and performing the operation, and letting me know if that fixes it for you.

Thanks!

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