Re: temp_buffers and work_mem and big temp tables

"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Tuesday, November 10, 2020, Wells Oliver <wells.oliver@gmail.com> wrote:
>> Hey all: I was wondering if someone might spell out which setting has more
>> impact on temporary tables being stored in memory versus disk? I have read
>> the docs but I thought I'd reach out and ask the community: I keep
>> increasing both in some scripts where Large Temp Tables are created, but
>> I'm wondering if it's more efficient just to use one or the other.

> IIUC work_mem has nothing to do with temporary tables.  All tables have a
> disk component and read/writes are done via buffers.

The temp_buffers setting controls how much temporary-table data can be
kept in a session's memory.  If you get to more than that, it spills out
to disk (or at least to the kernel's disk buffers).

            regards, tom lane