Re: Performance TODO items

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>
Cc: PostgreSQL-development <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: Performance TODO items
Date: 2001-07-30 17:15:40
Message-ID: 200107301715.f6UHFe310576@candle.pha.pa.us
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> > New TODO entries are:
> >
> > * Order duplicate index entries by tid
>
> In other words - add tid to index key: very old idea.

I was thinking during index creation, it would be nice to order them by
tid, but not do lots of work to keep it that way.

> > * Add queue of backends waiting for spinlock
>
> We shouldn't mix two different approaches for different
> kinds of short-time internal locks - in one cases we need in
> light lmgr (when we're going to keep lock long enough, eg for IO)
> and in another cases we'd better to proceed with POSIX' mutex-es
> or semaphores instead of spinlocks. Queueing backends waiting
> for spinlock sounds like nonsense - how are you going to protect
> such queue? With spinlocks? -:)

Yes, I guess so but hopefully we can spin waiting for the queue lock
rather than sleep. We could use POSIX spinlocks/semaphores now but we
don't because of performance, right?

Should we be spinning waiting for spinlock on multi-cpu machines? Is
that the answer?

--
Bruce Momjian | http://candle.pha.pa.us
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