Temp tables and LRU-K caching

From: Mike Mascari <mascarm(at)mascari(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Temp tables and LRU-K caching
Date: 2002-09-23 15:57:14
Message-ID: 3D8F39DA.4070802@mascari.com
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Hello.

I'm just curious as to the 7.3 status of a couple of things:

1. Back in Feb. I wrote (in regards to Oracle behavior):

"Unlike normal queries where blocks are added to the MRU end of
an LRU list, full table scans add the blocks to the LRU end of
the LRU list. I was wondering, in the light of the discussion of
using LRU-K, if PostgreSQL does, or if anyone has tried, this
technique?"

Bruce wrote:

"Yes, someone from India has a project to test LRU-K and MRU for
large table scans and report back the results. He will
implement whichever is best."

Did this make it into 7.3?

2. Gavin Sherry had worked up a patch so that temporary
relations could be dropped automatically upon transaction
commit. Did any of those patches it make it? I notice that
whenever I create a temporary table in a transaction, my HD
light blinks. Is this a forced fsync() causes by the fact that
the SQL standard defines temporary relations as surviving across
transactions? If so, I'd bet those of us who use
transaction-local temporary tables could get few drops more of
performance from an ON COMMIT drop patch w/o fsync.

Any thoughts?

Mike Mascari
mascarm(at)mascari(dot)com

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