From: Bruce Momjian <pgman@candle.pha.pa.us>
Message-Id: <200206080248.g582mPu22554@candle.pha.pa.us>
Subject: Re: Indexing timestamps
In-Reply-To: <20020606152814.P30776-100000@megazone23.bigpanda.com>
To: Stephan Szabo <sszabo@megazone23.bigpanda.com>
Date: Fri, 7 Jun 2002 22:48:25 -0400 (EDT)
Cc: Josh Berkus <josh@agliodbs.com>,
	Andre Schubert <andre.schubert@km3.de>, pgsql-sql@postgresql.org
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Stephan Szabo wrote:
> On Thu, 6 Jun 2002, Josh Berkus wrote:
> 
> >
> > Stephan,
> >
> > > Unfortunately you can't do that in that sort of syntax.  You'll
> > > need to create a function that returns the month and is marked
> > > as iscachable and use that function in the index creation and
> > > query.
> >
> > Hmmm.  I take it that NOW() is not ISCACHABLE, and that's Andre's indexing
> > problem?   What would be the pitfall of creating an alternate version of
> > NOW() that ISCACHABLE?
> 
> I believe it was not marked as iscachable.  I think it's now marked as
> static in dev sources which I would guess would mean that it could
> consider an index scan.  I think with care an iscachable function that
> just called now() would probably be safe for interactive queries.

We have all those new cacheable settings now to indicate things that can
change during the transaction, function call, or never.

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