| From: | Jim Nasby <jim(at)nasby(dot)net> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Greg Stark <stark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: MVCC catalog access |
| Date: | 2013-06-06 18:48:20 |
| Message-ID: | 51B0D974.1000607@nasby.net |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 6/5/13 3:49 PM, Robert Haas wrote:
> Now, I did find a couple that I thought should probably stick with
> SnapshotNow, specifically pgrowlocks and pgstattuple.
FWIW, I've often wished for a way to make all stat access transactional, across all the stats views. Perhaps that couldn't be done by default, but I'd love something like a function that would make a "snapshot" of all stats data as of one point. Even if that snapshot itself wasn't completely atomic, at least then you could query any stats views however you wanted and know that the info wasn't changing over time.
The reason I don't think this would work so well if done in userspace is how long it would take. Presumably making a complete backend-local copy of pg_proc etc and the stats file would be orders of magnitude faster than a bunch of CREATE TEMP TABLE's.
--
Jim C. Nasby, Data Architect jim(at)nasby(dot)net
512.569.9461 (cell) http://jim.nasby.net
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Simon Riggs | 2013-06-06 19:08:52 | Re: [PATCH]Tablesample Submission |
| Previous Message | Jeff Janes | 2013-06-06 18:41:49 | Re: Redesigning checkpoint_segments |