From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com>, Beena Emerson <memissemerson(at)gmail(dot)com> |
Cc: | tushar <tushar(dot)ahuja(at)enterprisedb(dot)com>, Prabhat Sahu <prabhat(dot)sahu(at)enterprisedb(dot)com>, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>, Kuntal Ghosh <kuntalghosh(dot)2007(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: increasing the default WAL segment size |
Date: | 2017-03-17 20:48:51 |
Message-ID: | 41d09289-0770-2866-c5d7-1894adbf57be@2ndquadrant.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 3/17/17 16:20, Peter Eisentraut wrote:
> On 3/16/17 21:10, Robert Haas wrote:
>> The changes to pg_standby seem to completely break the logic to wait
>> until the file has attained the correct size. I don't know how to
>> salvage that logic off-hand, but just breaking it isn't acceptable.
>
> I think we would have to extend restore_command with an additional
> placeholder that communicates the segment size, and add a new pg_standby
> option to accept that size somehow. And specifying the size would have
> to be mandatory, for complete robustness. Urgh.
Another way would be to name the WAL files in a more self-describing
way. For example, instead of
000000010000000000000001
000000010000000000000002
000000010000000000000003
name them (for 16 MB)
000000010000000001
000000010000000002
000000010000000003
Then, pg_standby and similar tools can compute the expected file size
from the file name length: 16 ^ (24 - fnamelen)
However, that way you can't actually support 64 MB segments. The next
jump up would have to be 256 MB (unless you want to go to a base other
than 16).
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2017-03-17 20:56:01 | Re: increasing the default WAL segment size |
Previous Message | Pavel Stehule | 2017-03-17 20:44:47 | Re: new set of psql patches for loading (saving) data from (to) text, binary files |