Re: Buffer Requests Trace - Mailing list pgsql-hackers

From Lucas Lersch
Subject Re: Buffer Requests Trace
Date
Msg-id CAGR3jZDr8zo1fw2TA_ZW42aSyBXpCp0k81YFHzqKrtYst00OQA@mail.gmail.com
Whole thread Raw
In response to Re: Buffer Requests Trace  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
I got the following numbers from my tpcc database:

Data size: ~6059MB
Index size: ~1390MB
Total size: ~7400MB

Even considering index-only scans, the ratio of around 50% of the database pages being accessed seems unrealistic to me.



On Wed, Oct 15, 2014 at 3:50 PM, Stephen Frost <sfrost@snowman.net> wrote:
* Lucas Lersch (lucaslersch@gmail.com) wrote:
> So is it a possible normal behavior that running tpcc for 10min only access
> 50% of the database? Furthermore, is there a guideline of parameters for
> tpcc (# of warehouses, execution time, operations weight)?

Depends- you may be aware that we support index-only scans in certain
situations.  This means that only the index page for a given relation
(and the visibility map) are accessed, and the heap is not.

        Thanks,

                Stephen



--
Lucas Lersch

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