Re: pgsql: Change default value of default_toast_compression to "lz4", when
On Tue, Mar 3, 2026 at 8:06 PM Michael Paquier <michael@paquier.xyz> wrote:
Change default value of default_toast_compression to "lz4", when available
...
Note: this is going to create some disturbance in the buildfarm, in
environments where lz4 is not installed.
I know there's no "good time" to change a configuration default, but
the timing now is especially unfortunate, because Mark maintains many
of those failing animals and he is traveling this week. Any chance we
can delay this patch a bit to coordinate, and keep the buildfarm
green?
--Jacob
Import Notes
Reply to msg id not found: E1vxdV4-002Hkq-1Y@gemulon.postgresql.orgReference msg id not found: E1vxdV4-002Hkq-1Y@gemulon.postgresql.org
Jacob Champion <jacob.champion@enterprisedb.com> writes:
I know there's no "good time" to change a configuration default, but
the timing now is especially unfortunate, because Mark maintains many
of those failing animals and he is traveling this week. Any chance we
can delay this patch a bit to coordinate, and keep the buildfarm
green?
By my count, two-thirds of the buildfarm is broken. (100 failing
animals, 56 working ones have reported since this commit.)
We would not normally tolerate leaving things that way for any
great length of time, and I don't think this commit should get
a pass. I think it needs to be reverted until a very much
larger fraction of buildfarm owners have prepared for it.
regards, tom lane
On Wed, Mar 04, 2026 at 09:01:06AM -0800, Jacob Champion wrote:
I know there's no "good time" to change a configuration default, but
the timing now is especially unfortunate, because Mark maintains many
of those failing animals and he is traveling this week. Any chance we
can delay this patch a bit to coordinate, and keep the buildfarm
green?
There will never be a perfect time for such a change. And after that
comes the fact I am out for most of the end of the dev cycle (spring
vacations and the end of the fiscal year here), so if we were to do
again the same thing in two weeks, I would not be able to follow up.
For now, I am collecting data about all the buildfarm members showing
in red, and I'll send direct notices to each owner through the day to
reduce the blast, in the shape of one email for each owner and for all
his/her hosts failing. I am wondering if this is going to display
bugs with LZ4, actually, the extend of the red-ness of the buildfarm
shows that we did not test it much on some niche places. I have
enabled it on my machines for a few years now, but it's clearly not a
popular choice.
--
Michael
On Wed, Mar 04, 2026 at 05:34:49PM -0500, Tom Lane wrote:
By my count, two-thirds of the buildfarm is broken. (100 failing
animals, 56 working ones have reported since this commit.)We would not normally tolerate leaving things that way for any
great length of time, and I don't think this commit should get
a pass. I think it needs to be reverted until a very much
larger fraction of buildfarm owners have prepared for it.
Hmm. If you guys feel strongly about it, I'd be OK to revert. Now
there is a way to split the pie into two halves: we can still
introduce DEFAULT_TOAST_COMPRESSION and use lz4 as default for the GUC
if lz4 is included in the build but, leave the switch of --with-lz4 to
--without-lz4 out of the equation. This choice would leave the
buildfarm in piece, and it still achieves the goal of enabling LZ4 in
TOAST by default, as long as --without-lz4 is used. As long as the
latter is achieved, the point of the change would be made.
Opinions?
--
Michael
On Thu, Mar 05, 2026 at 07:47:03AM +0900, Michael Paquier wrote:
Hmm. If you guys feel strongly about it, I'd be OK to revert. Now
there is a way to split the pie into two halves: we can still
introduce DEFAULT_TOAST_COMPRESSION and use lz4 as default for the GUC
if lz4 is included in the build but, leave the switch of --with-lz4 to
--without-lz4 out of the equation. This choice would leave the
buildfarm in piece, and it still achieves the goal of enabling LZ4 in
TOAST by default, as long as --without-lz4 is used. As long as the
latter is achieved, the point of the change would be made.
As I had the idea to press send too quickly, here's a reformulated
version. ;)
We can still introduce DEFAULT_TOAST_COMPRESSION and use lz4 as
default for the GUC if lz4 is included in the build but leave the
switch of --with-lz4 to --without-lz4 out of the equation. This
choice would leave the buildfarm in peace, and it still achieves the
goal of enabling LZ4 in TOAST by default, as long as --with-lz4 is
used. As long as the latter goal is achieved, the point of the change
would be made, at least partially.
--
Michael
Michael Paquier <michael@paquier.xyz> writes:
We can still introduce DEFAULT_TOAST_COMPRESSION and use lz4 as
default for the GUC if lz4 is included in the build but leave the
switch of --with-lz4 to --without-lz4 out of the equation. This
choice would leave the buildfarm in peace, and it still achieves the
goal of enabling LZ4 in TOAST by default, as long as --with-lz4 is
used. As long as the latter goal is achieved, the point of the change
would be made, at least partially.
That works for me as a temporary solution.
regards, tom lane
On Wed, Mar 4, 2026 at 3:22 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Michael Paquier <michael@paquier.xyz> writes:
We can still introduce DEFAULT_TOAST_COMPRESSION and use lz4 as
default for the GUC if lz4 is included in the build but leave the
switch of --with-lz4 to --without-lz4 out of the equation.
Thanks for the patches Michael; the farm looks much more verdant now.
--Jacob