| From: | Heikki Linnakangas <hlinnakangas(at)vmware(dot)com> |
|---|---|
| To: | Andres Freund <andres(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Merlin Moncure <mmoncure(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Amit Kapila" <amit(dot)kapila16(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Scaling shared buffer eviction |
| Date: | 2014-09-26 12:04:54 |
| Message-ID: | 54255666.4080101@vmware.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 09/25/2014 05:40 PM, Andres Freund wrote:
> There's two reasons for that: a) dynahash just isn't very good and it
> does a lot of things that will never be necessary for these hashes. b)
> the key into the hash table is*far* too wide. A significant portion of
> the time is spent comparing buffer/lock tags.
Hmm. Is it the comparing, or calculating the hash? We could precalculate
the hash for RelFileNode+ForkNumber, and store it RelationData. At a
lookup, you'd only need to mix in the block number.
- Heikki
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Heikki Linnakangas | 2014-09-26 12:21:28 | Re: delta relations in AFTER triggers |
| Previous Message | Amit Kapila | 2014-09-26 11:40:12 | Re: Scaling shared buffer eviction |