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* temp_buffers and work_mem and big temp tables
@ 2020-11-10 18:53 Wells Oliver <wells.oliver@gmail.com>
2020-11-10 19:04 ` Re: temp_buffers and work_mem and big temp tables David G. Johnston <david.g.johnston@gmail.com>
0 siblings, 1 reply; 3+ messages in thread
From: Wells Oliver @ 2020-11-10 18:53 UTC (permalink / raw)
To: pgsql-admin
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.
Thank you.
--
Wells Oliver
wells.oliver@gmail.com <wellsoliver@gmail.com>
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: temp_buffers and work_mem and big temp tables
2020-11-10 18:53 temp_buffers and work_mem and big temp tables Wells Oliver <wells.oliver@gmail.com>
@ 2020-11-10 19:04 ` David G. Johnston <david.g.johnston@gmail.com>
2020-11-10 19:32 ` Re: temp_buffers and work_mem and big temp tables Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 3+ messages in thread
From: David G. Johnston @ 2020-11-10 19:04 UTC (permalink / raw)
To: Wells Oliver <wells.oliver@gmail.com>; +Cc: pgsql-admin
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.
David J.
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: temp_buffers and work_mem and big temp tables
2020-11-10 18:53 temp_buffers and work_mem and big temp tables Wells Oliver <wells.oliver@gmail.com>
2020-11-10 19:04 ` Re: temp_buffers and work_mem and big temp tables David G. Johnston <david.g.johnston@gmail.com>
@ 2020-11-10 19:32 ` Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 3+ messages in thread
From: Tom Lane @ 2020-11-10 19:32 UTC (permalink / raw)
To: David G. Johnston <david.g.johnston@gmail.com>; +Cc: Wells Oliver <wells.oliver@gmail.com>; pgsql-admin
"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
^ permalink raw reply [nested|flat] 3+ messages in thread
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2020-11-10 18:53 temp_buffers and work_mem and big temp tables Wells Oliver <wells.oliver@gmail.com>
2020-11-10 19:04 ` David G. Johnston <david.g.johnston@gmail.com>
2020-11-10 19:32 ` Tom Lane <tgl@sss.pgh.pa.us>
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