Re: Does PostgreSQL cache all columns of a table after SELECT?

Hello Tim,

Can you send the EXPLAIN (BUFFERS, ANALYZE, VERBOSE) of your query? This will show you whether the plan is using caching or not.

> On 5 Jun 2023, at 09:15, Tim Schwenke <tim(at)trallnag(dot)com> wrote:
>
> Hello,
>
> I have the following table with the following columns:
>
> large_a: text (few dozen characters up to a few hundred)
> large_b: text (few dozen characters up to a few hundred)
>
> The table has several million rows. The DB is running on a large machine.
>
> I perform the following query:
>
> select large_a from table;
>
> The first query takes a few minutes. Afterwards I see that the cache in memory has grown. Next query only takes a few seconds.
>
> What I want to know:
>
> Does the cache also contain large_b? Or is only large_a cached? Assumption is that memory is large enough to fit everything.
>
>
>

Regards,
William Alves