From: Duncan Sands <duncan.sands@deepbluecap.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: Query planning on partitioned table causes postgres 13.4 to consume all memory
Date: Mon, 20 Sep 2021 14:10:17 +0200
Message-ID: <98598292-22bb-1304-656f-773f3677a0a8@deepbluecap.com> (raw)
In-Reply-To: <1556207.1632067384@sss.pgh.pa.us>
References: <4a3115d4-0fb2-e214-93e3-9a9d0974b883@deepbluecap.com>
<1556207.1632067384@sss.pgh.pa.us>
Hi Tom,
On 19/09/2021 18:03, Tom Lane wrote:
> Duncan Sands <duncan.sands@deepbluecap.com> writes:
>> [ planning DELETE on a thousand-partition table takes forever ]
>
> FWIW, this situation has been very much improved for v14 [1].
thanks, part (2) of that commit indeed looks like it should solve it.
Best wishes, Duncan.
> In older branches, the best advice I can give you is "don't use
> so many partitions". Especially not with hash partitioning,
> where the query WHERE clause generally won't translate to any
> useful pruning of the partitions.
>
> (Personally, I think that hash partitioning is an evil that
> we shouldn't have implemented at all. Or at least there
> should be stronger warnings about it in the manual than there
> are now.)
>
> regards, tom lane
>
> [1] https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=86dc90056
>
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To: pgsql-bugs@postgresql.org
Cc: duncan.sands@deepbluecap.com, tgl@sss.pgh.pa.us, pgsql-bugs@lists.postgresql.org
Subject: Re: Query planning on partitioned table causes postgres 13.4 to consume all memory
In-Reply-To: <98598292-22bb-1304-656f-773f3677a0a8@deepbluecap.com>
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