Re: Temp tables and LRU-K caching

Tom Lane wrote:
> Mike Mascari <mascarm(at)mascari(dot)com> writes:
>
>>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?
>
> No, we never heard back from that guy. It is still a live topic though.
> One of the Red Hat people was looking at it over the summer, and I think
> Neil Conway is experimenting with LRU-2 code right now.

Okay.

>
>>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?
>
>
> No they didn't; I forget whether there was any objection to his last try
> or it was just too late to get reviewed before feature freeze.

Nuts. Oh well. Hopefully for 7.4...

>
>>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?
>
>
> A completely-in-memory temp table is not really practical in Postgres,
> for two reasons: one being that its schema information is stored in
> the definitely-not-temp system catalogs, and the other being that we
> request allocation of disk space for each page of the table, even if
> it's temp.

I knew what I was asking made no sense two seconds after
clicking 'Send'. Unfortunately, there's no undo on my mail
client ;-).

Mike Mascari
mascarm(at)mascari(dot)com