Re: Relation 'pg_largeobject' does not exist

On 3/13/06, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Brandon Keepers <bkeepers(at)gmail(dot)com> writes:
> > Thanks for your quick response! I had actually just been trying that
> > (with 7.1) and came across another error:
>
> > NOTICE: ShmemAlloc: out of memory
> > NOTICE: LockAcquire: xid table corrupted
> > dumpBlobs(): Could not open large object. Explanation from backend:
> > 'ERROR: LockRelation: LockAcquire failed
>
> Ugh :-( How many blobs have you got, thousands? 7.0 stores each blob
> as a separate table, and I'll bet it is running out of lock table space
> to hold a lock on each one. My recollection is that we converted blob
> storage to a single pg_largeobject table precisely because of that
> problem.

Looks like there's over 17,000 blobs. :( But they're all very small,
if that makes a difference.

> What you'll need to do to get around this is to export each blob in a
> separate transaction (or at least no more than a thousand or so blobs
> per transaction). It looks like pg_dumplo might be easier to hack to do
> things that way --- like pg_dump, it puts a BEGIN/COMMIT around the
> whole run, but it's a smaller program and easier to move those commands
> in.

Unfortunately, I don't know C. Would someone be willing to help me
hack pg_dumplo in exchange for money?

> Another possibility is to increase the lock table size, but that would
> probably require recompiling the 7.0 backend. If you're lucky,
> increasing max_connections to the largest value the backend will support
> will be enough. If you've got many thousands of blobs there's no hope
> there, but if it's just a few thousand this is worth a try before you go
> hacking code.

I'm not the admin of the box that this database is on, so I don't have
any control over it. I'm working on moving it to a box that I am the
admin of. But anyway, it sounds like this wouldn't work anyway since
I have so many blobs.

> regards, tom lane

Thanks, again for your help, Tom!

Brandon