From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ron <ronljohnsonjr@gmail.com>
Cc: pgsql-admin@lists.postgresql.org
Subject: Re: need suggestion on querying big tables
Date: Tue, 06 Dec 2022 10:03:12 -0500
Message-ID: <3617537.1670338992@sss.pgh.pa.us> (raw)
In-Reply-To: <d926084d-63a7-854b-2d8d-459d33ec7f70@gmail.com>
References: <CAJuN1jj6NQDUjbMH=n4zry10JMJEZ8bRi=j6uA-3_108-Tq9cQ@mail.gmail.com>
<d926084d-63a7-854b-2d8d-459d33ec7f70@gmail.com>
Ron <ronljohnsonjr@gmail.com> writes:
> You've set effective_cache_size to 83%, when it should be at most 20%.
I think you're confusing effective_cache_size with the size of
shared buffers. It's meant to be an estimate of the total disk
cache space available, in both shared buffers and OS caches.
In any case, it's a fairly spongy parameter. It doesn't correspond
to any allocation actually made or requested in Postgres; it just
serves to tweak the planner's guesses about how expensive repeated
indexscans are likely to be. 83% of available RAM might be too
much, but it's probably not causing any real problems.
regards, tom lane
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: tgl@sss.pgh.pa.us, ronljohnsonjr@gmail.com, pgsql-admin@lists.postgresql.org
Subject: Re: need suggestion on querying big tables
In-Reply-To: <3617537.1670338992@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox