| From: | "tsunakawa(dot)takay(at)fujitsu(dot)com" <tsunakawa(dot)takay(at)fujitsu(dot)com> |
|---|---|
| To: | "k(dot)jamison(at)fujitsu(dot)com" <k(dot)jamison(at)fujitsu(dot)com> |
| Cc: | 'Kyotaro Horiguchi' <horikyota(dot)ntt(at)gmail(dot)com>, "amit(dot)kapila16(at)gmail(dot)com" <amit(dot)kapila16(at)gmail(dot)com>, "tgl(at)sss(dot)pgh(dot)pa(dot)us" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "andres(at)anarazel(dot)de" <andres(at)anarazel(dot)de>, "robertmhaas(at)gmail(dot)com" <robertmhaas(at)gmail(dot)com>, "tomas(dot)vondra(at)2ndquadrant(dot)com" <tomas(dot)vondra(at)2ndquadrant(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | RE: [Patch] Optimize dropping of relation buffers using dlist |
| Date: | 2020-11-12 04:13:35 |
| Message-ID: | TYAPR01MB2990C4EFE63F066F83D2A603FEE70@TYAPR01MB2990.jpnprd01.prod.outlook.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
The patch looks OK. I think as Thomas-san suggested, we can remove the modification to smgrnblocks() and don't care wheter the size is cached or not. But I think the current patch is good too, so I'd like to leave it up to a committer to decide which to choose.
I measured performance in a different angle -- the time DropRelFileNodeBuffers() and DropRelFileNodeAllBuffers() took. That reveals the direct improvement and degradation.
I used 1,000 tables, each of which is 1 MB. I used shared_buffers = 128 MB for the case where the traditional full buffer scan is done, and shared_buffers = 100 GB for the case where the optimization path takes effect.
The results are almost good as follows:
A. UNPATCHED
128 MB shared_buffers
1. VACUUM = 0.04 seconds
2. TRUNCATE = 0.04 seconds
100 GB shared_buffers
3. VACUUM = 69.4 seconds
4. TRUNCATE = 69.1 seconds
B. PATCHED
128 MB shared_buffers (full scan)
5. VACUUM = 0.04 seconds
6. TRUNCATE = 0.07 seconds
100 GB shared_buffers (optimized path)
7. VACUUM = 0.02 seconds
8. TRUNCATE = 0.08 seconds
So, I'd like to mark this as ready for committer.
Regards
Takayuki Tsunakawa
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Thomas Munro | 2020-11-12 04:26:39 | Re: Background writer and checkpointer in crash recovery |
| Previous Message | k.jamison@fujitsu.com | 2020-11-12 04:00:14 | RE: [Patch] Optimize dropping of relation buffers using dlist |