Re: Well, we seem to be proof against cache-inval problems now

Can this now be marked as done?

* Modification of pg_class can happen while table in use by another
backend. Might lead to MVCC inside of syscache

> I just finished running the parallel regress tests with inval.c rigged
> to flush the relcache and syscache at every available opportunity,
> that is anytime we could recognize a shared-cache-inval message from
> another backend (see diff below). This setup gives a whole new universe
> of meaning to the word "slow" --- it took *three full days* to run the
> standard "make check" procedure, including eighteen hours just to do the
> "vacuum template1" part of initdb. I kid you not. But it worked.
> Looks like the unexpected-cache-entry-drop class of problems are indeed
> gone.
>
> BTW, the reason the diff is rigged not to allow recursive cache flush
> is not that it wouldn't work, it's that I didn't expect to live long
> enough to finish such a test. I didn't originally have that restriction
> in there (and indeed found a bug that way: relcache flush could go into
> an infinite loop if hit with another SI inval before it'd finished the
> initial flush). After fixing that bug, initdb was making steady
> progress, but not at a rate that I wanted to wait out...
>
> regards, tom lane
>
> *** src/backend/utils/cache/inval.c.orig Wed Nov 15 23:57:44 2000
> --- src/backend/utils/cache/inval.c Mon Jan 1 17:27:53 2001
> ***************
> *** 643,649 ****
> --- 643,661 ----
> elog(DEBUG, "DiscardInvalid called");
> #endif /* defined(INVALIDDEBUG) */
>
> + #if 1
> + /* DEBUG CHECK ONLY ... force cache reset at any opportunity */
> + static bool inReset = false;
> +
> + if (! IsBootstrapProcessingMode() && !inReset)
> + {
> + inReset = true;
> + ResetSystemCaches();
> + inReset = false;
> + }
> + #else
> InvalidateSharedInvalid(CacheIdInvalidate, ResetSystemCaches);
> + #endif
> }
>
> /*
>

--
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