Re: [HACKERS] How To free resources used by large object Relations?

Maurice Gittens wrote:
> 
> Hi,
> 
> I've changed the large object memory managment strategy to ensure that
> each large object has it's own memory context.
> This way I can free all memory for a large object when I lo_close
> is called for it's oid. This seems to work.
> 
> I've noticed that the heap_close function used to close the heap used
> by a large object doesn't really do any thing. (It calls RelationClose
> which decrements some reference count).
> 
> Somehow I have to free the relation from the cache in the following
> situations:
> 1. In a transaction I must free the stuff when the transaction is
> commited/aborted.

Backend does it, don't worry.

> 2. Otherwise it must happen when lo_close is called.

It seems that you can't remove relation from cache untill
commit/abort, currently: backend uses local cache to unlink
files of relations created in transaction if abort...
We could change relcache.c:RelationPurgeLocalRelation()
to read from pg_class directly...

But how many LO do you create in single xact ?
Is memory allocated for cache so big ?

Vadim