From: PG Doc comments form <noreply@postgresql.org>
To: pgsql-docs@lists.postgresql.org
Cc: splarv@ya.ru
Subject: explanation for random_page_cost is outdated
Date: Thu, 27 Feb 2020 14:48:44 +0000
Message-ID: <158281492445.30439.15446208692175239579@wrigleys.postgresql.org> (raw)
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/12/runtime-config-query.html
Description:
Explanation for random_page_cost is rather outdated, because it did only for
case of mechanical hdd. But all modern database servers, which I know, made
upon SSD. Do or not do default value for random_page_cost equal to 1 is the
question, but, IMHO, at list in the documentation about random_page_cost
need to add in a speculation about SSD.
It's important because a business programming now is mostly web programming.
Most database is poorly designed by web programmer, tables looked like a
primary key and a huge json (containing all) with large gin index upon it.
Now I am seeing a table with a GIN index 50% of the table size. The database
is on SSD, of cause. With default random_page_cost=4 GIN index don't used
by planner, but with random_page_cost=1 the result may be not excellent, but
acceptable for web programmers.
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To: pgsql-docs@postgresql.org
Cc: noreply@postgresql.org, pgsql-docs@lists.postgresql.org, splarv@ya.ru
Subject: Re: explanation for random_page_cost is outdated
In-Reply-To: <158281492445.30439.15446208692175239579@wrigleys.postgresql.org>
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