PG 14 pg_basebackup accepts --compress=server-zst option
https://www.postgresql.org/docs/14/app-pgbasebackup.html doesn't mention
"--compress=[{client|server}-]method". That first appears in the v15 docs.
And yet pg_basebackup doesn't complain about an invalid option.
(Technically, this is a bug; I first noticed it a week after copying a
script from a PG 15 server to five PG 14 servers, and running it quite a
few times without fail.)
$ pg_basebackup \
> --pgdata=$PGDATA \
> --dbname=service=basebackup \
> --verbose --progress \
> --checkpoint=fast \
> --write-recovery-conf \
> --wal-method=stream \
> --create-slot --slot=pgstandby1 \
> --compress=server-zst ; echo $?
pg_basebackup: initiating base backup, waiting for checkpoint to complete
pg_basebackup: checkpoint completed
pg_basebackup: write-ahead log start point: 256/BC28 on timeline 1
pg_basebackup: starting background WAL receiver
pg_basebackup: created replication slot "pgstandby1"
42567083/42567083 kB (100%), 1/1 tablespace
pg_basebackup: write-ahead log end point: 256/BC000138
pg_basebackup: waiting for background process to finish streaming ...
pg_basebackup: syncing data to disk ...
pg_basebackup: renaming backup_manifest.tmp to backup_manifest
pg_basebackup: base backup completed
0
Re: PG 14 pg_basebackup accepts --compress=server-zst option
Hi
On Fri, Jun 7, 2024 at 6:54 AM Ron Johnson wrote:
>
> https://www.postgresql.org/docs/14/app-pgbasebackup.html doesn't mention
> "--compress=[{client|server}-]method". That first appears in the v15 docs.
>
> And yet pg_basebackup doesn't complain about an invalid option.
> (Technically, this is a bug; I first noticed it a week after copying a
> script from a PG 15 server to five PG 14 servers, and running it quite a
> few times without fail.)
>
If the support is removed then it should be mentioned in the official
documentation.
Regards
Kashif Zeeshan
Bitnine Global
>
> $ pg_basebackup \
> > --pgdata=$PGDATA \
> > --dbname=service=basebackup \
> > --verbose --progress \
> > --checkpoint=fast \
> > --write-recovery-conf \
> > --wal-method=stream \
> > --create-slot --slot=pgstandby1 \
> > --compress=server-zst ; echo $?
> pg_basebackup: initiating base backup, waiting for checkpoint to complete
> pg_basebackup: checkpoint completed
> pg_basebackup: write-ahead log start point: 256/BC28 on timeline 1
> pg_basebackup: starting background WAL receiver
> pg_basebackup: created replication slot "pgstandby1"
> 42567083/42567083 kB (100%), 1/1 tablespace
> pg_basebackup: write-ahead log end point: 256/BC000138
> pg_basebackup: waiting for background process to finish streaming ...
> pg_basebackup: syncing data to disk ...
> pg_basebackup: renaming backup_manifest.tmp to backup_manifest
> pg_basebackup: base backup completed
> 0
>
>
Re: PG 14 pg_basebackup accepts --compress=server-zst option
On Thursday, June 6, 2024, Kashif Zeeshan wrote:
> Hi
>
> On Fri, Jun 7, 2024 at 6:54 AM Ron Johnson
> wrote:
>
>>
>> https://www.postgresql.org/docs/14/app-pgbasebackup.html doesn't mention
>> "--compress=[{client|server}-]method". That first appears in the v15
>> docs.
>>
>> And yet pg_basebackup doesn't complain about an invalid option.
>> (Technically, this is a bug; I first noticed it a week after copying a
>> script from a PG 15 server to five PG 14 servers, and running it quite a
>> few times without fail.)
>>
>
Seems a bit suspect, but as your script doesn’t mention tar the option
itself is apparently ignored, I guess silently. Assuming this isn’t an
actual regression in behavior in a patch-released older version I don’t see
us adding an error message at this point.
> If the support is removed then it should be mentioned in the official
> documentation.
>
Support wasn’t removed. Re-read the email and check the version/times
being mentioned again.
David J.
Re: PG 14 pg_basebackup accepts --compress=server-zst option
On Fri, Jun 7, 2024 at 12:32 AM David G. Johnston <
david.g.johns...@gmail.com> wrote:
> On Thursday, June 6, 2024, Kashif Zeeshan wrote:
>
>> Hi
>>
>> On Fri, Jun 7, 2024 at 6:54 AM Ron Johnson
>> wrote:
>>
>>>
>>> https://www.postgresql.org/docs/14/app-pgbasebackup.html doesn't
>>> mention "--compress=[{client|server}-]method". That first appears in the
>>> v15 docs.
>>>
>>> And yet pg_basebackup doesn't complain about an invalid option.
>>> (Technically, this is a bug; I first noticed it a week after copying a
>>> script from a PG 15 server to five PG 14 servers, and running it quite a
>>> few times without fail.)
>>>
>>
> Seems a bit suspect, but as your script doesn’t mention tar the option
> itself is apparently ignored, I guess silently.
>
Does this mean that "--compress=server-zst" is only relevant with
--format=tar?
> Assuming this isn’t an actual regression in behavior in a patch-released
> older version
>
My apologies for not mentioning the version: 14.12-1PGDG-rhel8.
> I don’t see us adding an error message at this point.
>
Me neither. It just seemed odd.
Re: PG 14 pg_basebackup accepts --compress=server-zst option
Ron Johnson writes:
> On Fri, Jun 7, 2024 at 12:32 AM David G. Johnston <
> david.g.johns...@gmail.com> wrote:
>> I don’t see us adding an error message at this point.
> Me neither. It just seemed odd.
v14 thinks the argument of --compress must be an integer, and doesn't
really bother with any syntax error checks:
case 'Z':
compresslevel = atoi(optarg);
if (compresslevel < 0 || compresslevel > 9)
{
pg_log_error("invalid compression level \"%s\"", optarg);
exit(1);
}
break;
In your example, atoi() will return zero and it will sail along with
no compression. Releases 15 and up have more complex ideas of what
--compress can specify, and seem to syntax-check it much more
thoroughly.
This is a pretty common coding pattern, so I can't get excited
about changing it, especially not in long-stable branches.
regards, tom lane
