Re: 8.1 index corruption woes

Alvaro Herrera <alvherre@commandprompt.com> writes:
> We've detected what I think is some sort of index corruption in 8.1.
> The server is running 8.1.11, so AFAICT the problem with truncated pages
> in vacuum is already patched and accounted for (i.e. we reindexed, and a
> bit later the problem presented itself again).  There haven't been any
> relevant fixes after that AFAICT.

> What we see is that after a bit of updating the index, it starts having
> tuples that poing to heap entries which are marked unused.

Do you actually see any observed problem, or is this conclusion based
entirely on your pg_filedump analysis?

I suspect a problem with your analysis script, although a quick scan
of the code didn't find an issue.

Another point to keep in mind, if you are trying to analyze files
belonging to a live database, is that what you can see in the filesystem
may not be the "current" contents of every page.  For typical access
patterns it'd be unsurprising for the visible index pages to lag behind
those of the heap, since they'd be "hotter" and tend to stay in shared
buffers longer.
        regards, tom lane