Re: tuptoaster.c must *not* use SnapshotAny

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.

Really? So what you're saying means that while vacuum is
running there's a window where one tuple can exist multiple
times and just the fact that other backends can see the
vacuum transaction alive prevents them from showing up? That
doesn't sound really good to me.

Jan

>
> 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
>
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