Re: how to investigate GIN fast updates and cleanup cycles? - Mailing list pgsql-general

From Steve Kehlet
Subject Re: how to investigate GIN fast updates and cleanup cycles?
Date
Msg-id CA+bfosF=tpA0TKQDz19bSGMjSyMoUVaLn7FD5J3vNiYrGKLNHw@mail.gmail.com
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In response to Re: how to investigate GIN fast updates and cleanup cycles?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On Fri, Aug 28, 2015 at 11:18 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
It looks like a VACUUM will do the cleanup during the first ginbulkdelete
call, so you could probably handle this by running a manual "VACUUM
VERBOSE" with the smallest possible maintenance_work_mem, and canceling it
as soon as you see something reported about the GIN index.

Since I'm back to running VACUUM VERBOSE by hand, can you clarify for me how reducing maintenance_work_mem (currently 512MB) will speed it up? Will it work in smaller chunks? So just do something like:

set maintenance_work_mem = '32MB';
VACUUM VERBOSE my_table';

How do I determine the smallest value possible? Just start small (32MB?) and see if it fails, and increase until it doesn't?

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