Re: tuptoaster.c must *not* use SnapshotAny - Mailing list pgsql-hackers

From Command Prompt, Inc.
Subject Re: tuptoaster.c must *not* use SnapshotAny
Date
Msg-id Pine.LNX.4.30.0201160944480.30961-100000@commandprompt.com
Whole thread Raw
In response to tuptoaster.c must *not* use SnapshotAny  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: tuptoaster.c must *not* use SnapshotAny  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Josh Drake here: Although I know that development has pretty much ceased
on the 7.1 series. This bug, is potentially very serious for those who
have the problem.

The last time this came up (that I can find) is in August of 2001, so the
bug is not frequent that we are aware of. However, as it appears the fix
is simple should we apply a 7.1.3.1 or 7.1.4 that fixes this issue?


J


> On Tue, 15 Jan 2002, Tom Lane wrote:

> The tuple toaster currently fetches toast-table rows using SnapshotAny.
> This is quite uncool, because it will in fact find *any* row.  Including
> dead rows resulting from an aborted (or, in 7.2, still-in-progress)
> VACUUM.
>
> I believe this is the explanation for a problem report I'm currently
> chasing from Joshua Drake:
>
> digivision2=# select * from change_log;
> ERROR:  chunk 1 for toast value 3388774 appears multiple times
>
> (there are some thousands of rows with similar problems)
>
> I suggest SnapshotSelf instead.  Comments anyone?
>
>             regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>

-- 
by way of pgsql-hackers@commandprompt.com



pgsql-hackers by date:

Previous
From: Peter Eisentraut
Date:
Subject: Re: Procedural language permissions and consequences
Next
From: Tom Lane
Date:
Subject: Re: tuptoaster.c must *not* use SnapshotAny