Re: [GENERAL] Concurrency problem building indexes

On 4/24/06 11:02 PM, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> [ shrug... ] Worksforme.
>
> There is a short interval at the end of the first CREATE INDEX on the
> table where the problem would happen if another CREATE INDEX tries to
> modify the pg_class row before the first one's committed. That would be
> hard to hit with any regularity though. Subsequent CREATE INDEXes after
> that should be completely reliable. If you are modifying the table
> while it's being indexed, then the same small window would apply for
> each CREATE INDEX not just the first ... but you didn't admit to that.
>
> Care to put together a self-contained test case?

I think I've got a reasonably small test case I can send you in the morning.
I did a pg_dumpall and removed the index creation commands. The first time
I run the index build, I usually get at least one occurrence.

Where do you want me to send it to?

Of course, since your hardware is different, it may not show up since it
appears to be a timing thing.. I'm on a PB G4 1Ghz.

Wes