| From: | Peter Geoghegan <pg(at)heroku(dot)com> |
|---|---|
| To: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Cc: | Jim Nasby <jim(at)nasby(dot)net>, Robert Haas <robertmhaas(at)gmail(dot)com>, Andres Freund <andres(at)2ndquadrant(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Subject: | Re: Clock sweep not caching enough B-Tree leaf pages? |
| Date: | 2014-04-25 17:45:53 |
| Message-ID: | CAM3SWZQ1mqbeSuNEj=6OF6AqJp8qYO8MxnZxTLSEU8FyviEsMQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
I've now done a non-limited comparative benchmark of master against
the patch (once again, with usage_count starting at 6, and
BM_MAX_USAGE_COUNT at 30) with a Gaussian distribution. Once again,
the distribution threshold used was consistently 5.0, causing the
patched pgbench to report for each test:
transaction type: Custom query
scaling factor: 5000
standard deviation threshold: 5.00000
access probability of top 20%, 10% and 5% records: 0.68269 0.38293 0.19741
Results are available from:
http://postgres-benchmarks.s3-website-us-east-1.amazonaws.com/3-sec-delay-gauss/
--
Peter Geoghegan
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