Re: Database possible corruption , unsolvable mystery

> Hrm, you know that you -should- upgrade to at least the latest 7.4
> (7.4.13 I think is the most recent). looking from the
> changelogs, there are a few bugs that you could be hitting;
>
> 7.4.10
> * Fix race condition in transaction log management There
> was a narrow window in which an I/O operation could be
> initiated for the wrong page, leading to an Assert failure or
> data corruption.
>
> 7.4.9
> * Improve checking for partially-written WAL pages
> * Fix error that allowed VACUUM to remove ctid chains too
> soon, and add more checking in code that follows ctid links.
> This fixes a long-standing problem that could cause crashes
> in very rare circumstances.
>
> 7.4.8
> * Repair race condition between relation extension and
> VACUUMThis could theoretically have caused loss of a page's
> worth of freshly-inserted data, although the scenario seems
> of very low probability. There are no known cases of it
> having caused more than an Assert failure
>
> and these are only the ones that appear 'notably' in the
> changelog.
> In short, I -really- -would- -strongly- -advise- you
> upgrading to 7.4.13. Personally, I would have made this my
> first step, especially if your data is important.
>
> There is no need for a dump/reload between minor point releases.
> Although there is a security fix in 7.4.8.
>
> Since the db is in a state of 'down' or repair, why not
> do it now ?
> two birds, one stone.

Thank you , this might be a good solution , but we have a bigger upgrade
comming for 8.1.x later on,
but considering that other things out of our hands might occur , we
might seriously look into it after fixing
the current problems :) [because we dont think that upgrading right now
will magicly fix the problem we are having.]
And on about 10 database [all 7.4.6] it is the first time this occur ,
and the symtom is really on one table, considering
a few terabytes of data sparsed accros a few db, we might have been
lucky yet but as of now its the first time
we can see performance hit only on "delete".

But thanks alot for the hint. [even tho we never had some unexpected
data failure/crash] beside this out of control
human power failure that might have been the root of this [the database
is still dumping ...few gigs :)]

Thanks alot all for the help,and if we find the root cause we will give
feed back.

-elz

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