Re: Accessing schema data in information schema

Hannu Krosing wrote:

> I guess we can't easily start locking some subarea of a page, say 256
> byte subpage, or just the tuple.

> OTOH it may be possible as we don't need to lock page header for
> sequences as the tuple is updated in place and will not change in size.

Huh, we _can_ lock individual tuples, using LockTuple() (or rather,
heap_lock_tuple).  Since the tuple is modified in place, there's no need
to lock the whole page.

> OTOOH, I'm afraid we still need to WAL the whole page, so the savings
> will be marginal.

Huh, why?  We can just keep the current WAL logging for sequences, or
something very similar, can't we?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.