Re: [GENERAL] 9.4.1 -> 9.4.2 problem: could not access status of transaction 1 - Mailing list pgsql-hackers

From Andres Freund
Subject Re: [GENERAL] 9.4.1 -> 9.4.2 problem: could not access status of transaction 1
Date
Msg-id 53F413D8-2BF5-4C9C-90B0-F114A19DF372@anarazel.de
Whole thread Raw
In response to Re: [GENERAL] 9.4.1 -> 9.4.2 problem: could not access status of transaction 1  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: [GENERAL] 9.4.1 -> 9.4.2 problem: could not access status of transaction 1
List pgsql-hackers
On June 8, 2015 7:06:31 PM GMT+02:00, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
>Andres Freund wrote:
>
>> A first version to address this problem can be found appended to this
>> email.
>>
>> Basically it does:
>> * Whenever more than MULTIXACT_MEMBER_SAFE_THRESHOLD are used, signal
>>   autovacuum once per members segment
>> * For both members and offsets, once hitting the hard limits, signal
>>   autovacuum everytime. Otherwise we loose the information when
>>   restarting the database, or when autovac is killed. I ran into this
>a
>>   bunch of times while testing.
>
>I might be misreading the code, but PMSIGNAL_START_AUTOVAC_LAUNCHER
>only
>causes things to happen (i.e. a new worker to be started) when
>autovacuum is disabled.  If autovacuum is enabled, postmaster receives
>the signal and doesn't do anything about it, because the launcher is
>already running.  Of course, regularly scheduled autovac workers will
>eventually start running, but perhaps this is not good enough.

Well that's just the same for the plain xid precedent? I'd not mind improving further, but that seems like a separate
thing.

Andres

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Please excuse brevity and formatting - I am writing this on my mobile phone.


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