Re: Bug: Unreferenced temp tables disables vacuum to update xid

"Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:

> On Mon, 7 Jan 2008 11:58:29 -0500 (EST)
> Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>
>> I assume it is this TODO item:
>>
>> o Prevent long-lived temporary tables from causing frozen-xid
>> advancement starvation
>>
>> The problem is that autovacuum cannot vacuum them to set
>> frozen xids; only the session that created them can do that.
>> http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php
>>
>> but am confused how the fix worked. Have all of these backends been
>> active for 1 billion transactions?
>
> Well it certainly appears that the TODO item is related. However there
> are a couple of differences.

Yeah, it seems there are two bugs here. 1) temporary tables prevent frozen-xid
advancement and 2) if a process dies at the wrong moment it's possible to
temporary tables. Either one alone is pretty minor but I guess the combination
is lethal.

--
Gregory Stark
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