Re: ON COMMIT temp table handling

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Tom Lane wrote:
> >> Why is temp table handling in need of looking into xact.c's private
> >> state? There is no other AtEOXact routine anywhere that does this.
> >> ISTM either the above code is wrong, or every other AtEOXact routine
> >> is wrong.
>
> > I looked at that. The basic issue is that Gavin wants special handling
> > for ON COMMIT, meaning he only wants to activate the ON COMMIT code when
> > the transaction is committed and it is an end block, or it is not a
> > commit but it is an abort.
>
> I eventually realized that the problem is that his AtEOXact routine
> needs to be split in two pieces. The actual ON COMMIT DROP or DELETE
> ROWS action has to happen *before* we record transaction commit.
> (Imagine what happens if we get an error while doing that part.)
> But the cleanup of the list of on-commit objects should happen
> afterwards. I think if you look at the version I committed this
> afternoon, you'll be much happier.

Now, that makes sense.

> > I have to say I am confused by the various
> > TBLOCK values and their progression. I can't find any comments on them
> > and the code seems contorted.
>
> I think xact.c has more generality than it actually needs --- some of
> the TBLOCK states could probably be eliminated. I'm not really excited
> about rewriting it though; it works and has worked for years.

Yep, over generalized is the word for it. Let me see if I can add some
comments.

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