Thread: checkpoint_segments upgrade recommendation?
The release notes say that checkpoint_segments has been replaced by max_wal_size and min_wal_size, but there is no indication on how to convert between the old and new settings. I think a lot of people will have checkpoint_segments delicately tuned, so we should at least give them a hint on how to carry that forward in spirit.
On Fri, Oct 16, 2015 at 2:52 PM, Peter Eisentraut <peter_e@gmx.net> wrote: > The release notes say that checkpoint_segments has been replaced by > max_wal_size and min_wal_size, but there is no indication on how to > convert between the old and new settings. I think a lot of people will > have checkpoint_segments delicately tuned, so we should at least give > them a hint on how to carry that forward in spirit. Yeah, it would be nice to have some guidance about that. But do we know what the guidance should be? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
On Sat, Oct 17, 2015 at 4:45 AM, Robert Haas <robertmhaas@gmail.com> wrote:
On Fri, Oct 16, 2015 at 2:52 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
> The release notes say that checkpoint_segments has been replaced by
> max_wal_size and min_wal_size, but there is no indication on how to
> convert between the old and new settings. I think a lot of people will
> have checkpoint_segments delicately tuned, so we should at least give
> them a hint on how to carry that forward in spirit.
Yeah, it would be nice to have some guidance about that. But do we
know what the guidance should be?
I think that we should just suggest a reverse formula of the maximum soft limit of checkpoint_segments for max_wal_size in the release notes of 9.5, basically:
(3 * your_old_checkpoint_segments + 1) * 16MB = max_wal_sizeRegards,
--
Michael
On 10/17/15 10:25 AM, Michael Paquier wrote: > I think that we should just suggest a reverse formula of the maximum > soft limit of checkpoint_segments for max_wal_size in the release notes > of 9.5, basically: > (3 * your_old_checkpoint_segments + 1) * 16MB = max_wal_size How about this patch? (Actually, I'd remove the + 1 to make the numbers come out rounder.)
Attachment
On Wed, Oct 21, 2015 at 3:11 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
On 10/17/15 10:25 AM, Michael Paquier wrote:
> I think that we should just suggest a reverse formula of the maximum
> soft limit of checkpoint_segments for max_wal_size in the release notes
> of 9.5, basically:
> (3 * your_old_checkpoint_segments + 1) * 16MB = max_wal_size
How about this patch?
(Actually, I'd remove the + 1 to make the numbers come out rounder.)
Removing the + 1 is fine for me.
+ been removed. Its place it taken by the new
"Its place is taken".
Other than those little things this looks fine to me.
Regards,
--
Michael