Re: Tables dissapearing

On Aug 27, 2007, at 4:44 PM, Kamil Srot wrote:

>> Also, in your original post you mentioned a "proprietal CMS
>> system". Is this proprietary to your company or one that you've
>> purchased? The fact that the same table going on multiple dbs all
>> being run by that CMS system certainly makes it worthy of suspicion.
>>
> This is software developed in our company... so I'm sure it's not
> duing aby schema manipulation. I'm actually senior developer of
> this project by accident :-)

That doesn't mean that there's not some whacked out race condition
causing corruption. I'm just saying, keep exploring every option.
Saying, "I wrote and am in charge of that so I know it didn't do it"
is bad. You should at the very least have someone else, as well as
you, review any code that touches that table.

>
> The strange thing is, all the projects are completelly
> independend... has its own DB, folder with scripts, different
> data... just the DB user is the same... so it's higly unprobable,
> that it'll do 2 similar errors in thow distinct databases at nearly
> the same time...

Just the DB and your CMS. Given that setup, if your CMS is causing
this to happen on one DB, it actually is not unlikely that it would
do it to the others.

> When this problem appeared for the first time, I had clearly the
> wraparound problem... I did vacuum it and partially restored the
> data... but in some meantime, I had commands like \dt showing all
> relations twice... (some system catalog problem)... then I did full
> dump and restore along with upgrade to newest pgsql server
> software... this duplicity was gone and never appeared again.
>
> From above mentioned duplications of relatio names and what Tom
> wrote recently (doesn't see like WA problem), it looks like the
> relation name is/gets corrupted in some way and this corruption is
> internally taken over to another instance of relation named the
> same but in another database... but I know - it's too speculative.

Is it the same instance of your CMS managing each of the databases or
a separate instance per DB? Also, how often has this happened?
Since wraparound has been ruled out, it's hard to say what else could
be the culprit or what to look at and do next without any more
specific details about the system at the time(s) this has happened.
What kind of monitoring do you have set up on your DBs? Have you
verified that the table's files are still on disk after it's
"disappeared"?

Erik Jones

Software Developer | Emma®
erik(at)myemma(dot)com
800.595.4401 or 615.292.5888
615.292.0777 (fax)

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