From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: logical decoding / rewrite map vs. maxAllocatedDescs
Date: Thu, 16 Aug 2018 17:07:17 +0200
Message-ID: <82d51b43-3b98-38e5-2e37-a8959b13ef49@2ndquadrant.com> (raw)
In-Reply-To: <53047b69-9af7-1399-d190-6d7db60a7dd8@2ndquadrant.com>
References: <20180809174746.aa6rbpsu4zjipzif@alvherre.pgsql>
<b346c3eb-0e65-29ec-47db-0d9a46feaa2c@2ndquadrant.com>
<20180810211340.nlgyfa7jlmkjcs5m@alap3.anarazel.de>
<79a0c7f4-89fb-cf8d-82eb-5a7ca8e08d56@2ndquadrant.com>
<6899.1533996956@sss.pgh.pa.us>
<53047b69-9af7-1399-d190-6d7db60a7dd8@2ndquadrant.com>
On 08/11/2018 04:18 PM, Tomas Vondra wrote:
> On 08/11/2018 04:15 PM, Tom Lane wrote:
>> Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
>>>>> On 08/09/2018 07:47 PM, Alvaro Herrera wrote:
>>>>>> Actually, it seems to me that ApplyLogicalMappingFile is just leaking
>>>>>> the file descriptor for no good reason.
>>
>>> I think the fix can be as simple as attached ... I'm mostly afk for the
>>> weekend, so I'll commit & backpatch on Monday or so.
>>
>> LGTM. While you're at it, would you fix the misspelling three lines
>> below this?
>>
>> * Check whether the TransactionOId 'xid' is in the pre-sorted array 'xip'.
>> ^
>
> Sure.
>
I've pushed this, and backpatched it all the way back to 9.4 where
logical decoding was introduced.
While this resolves the way to run out of file descriptors, I wonder if
there are other trivial ways to trigger it (say, long-running
transaction spanning many 'vacuum full pg_class' runs). Not sure, will
try later.
The other question is whether errors are handled correctly - as reported
initially, I've seen this to trigger
ERROR: XX000: subtransaction logged without previous top-level txn record
I assume just fixing the error did not really fix that, so that if
something else fails we might end up in the same state.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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Cc: tomas.vondra@2ndquadrant.com, tgl@sss.pgh.pa.us, andres@anarazel.de, alvherre@2ndquadrant.com
Subject: Re: logical decoding / rewrite map vs. maxAllocatedDescs
In-Reply-To: <82d51b43-3b98-38e5-2e37-a8959b13ef49@2ndquadrant.com>
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