| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
|---|---|
| To: | Greg Sabino Mullane <greg(at)endpoint(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Overhead cost of Serializable Snapshot Isolation |
| Date: | 2011-10-10 19:30:35 |
| Message-ID: | 4E9347DB.7090804@enterprisedb.com |
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| Lists: | pgsql-hackers |
On 10.10.2011 21:25, Greg Sabino Mullane wrote:
> I agree it is better versus SELECT FOR, but what about repeatable read versus
> the new serializable? How much overhead is there in the 'monitoring of
> read/write dependencies'? This is my only concern at the moment. Are we
> talking insignificant overhead? Minor? Is it measurable? Hard to say without
> knowing the number of txns, number of locks, etc.?
I'm sure it does depend heavily on all of those things, but IIRC Kevin
ran some tests earlier in the spring and saw a 5% slowdown. That feels
like reasonable initial guess to me. If you can run some tests and
measure the overhead in your application, it would be nice to hear about it.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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