log_line_prefix and JSON log format
Hackorum builds and tests every patch posted to the lists, not only commitfest submissions. This is Hackorum's own CI rather than the PostgreSQL project's, and it is still under testing - please report anything that looks wrong.
This thread has been committed, so CI has stopped here. Anything below is the last result it produced.
You can run a PostgreSQL built from this patch straight from Docker, with no checkout and no build:
docker run --rm -p 5432:5432 ghcr.io/hackorum-dev/postgres-patch:t253941psql -h localhost -U postgresBuilt from patchset v2 (message #2), September 25, 2026 at 03:24 PM.
Every patchset is also pushed to a branch of our PostgreSQL fork, so you can check out the same tree CI built. Without a PostgreSQL checkout:
git clone --branch t253941_2 https://github.com/hackorum-dev/postgres.gitIn a checkout you already have, add the fork once:
git remote add hackorum https://github.com/hackorum-dev/postgres.gitthen, for this patchset and every later one:
git fetch hackorum t253941_2 && git checkout t253941_2Patchset v2 (message #2) is on t253941_2
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/18/index.html
Description:
I noticed, that it not documented anywhere what log_line_prefix will do, if
log_destination = 'jsonlog' (Or CSV). From my tests it seems it is ignored
and does nothing. But we weren't sure and would be helpful to have this
documented.
On Fri, 2026-09-25 at 09:32 +0000, PG Doc comments form wrote:
Page: https://www.postgresql.org/docs/18/index.html
I noticed, that it not documented anywhere what log_line_prefix will do, if
log_destination = 'jsonlog' (Or CSV). From my tests it seems it is ignored
and does nothing. But we weren't sure and would be helpful to have this
documented.
True; here is a patch.
Yours,
Laurenz Albe
Laurenz Albe <laurenz.albe@cybertec.at> writes:
On Fri, 2026-09-25 at 09:32 +0000, PG Doc comments form wrote:
I noticed, that it not documented anywhere what log_line_prefix will do, if
log_destination = 'jsonlog' (Or CSV). From my tests it seems it is ignored
and does nothing. But we weren't sure and would be helpful to have this
documented.
True; here is a patch.
This wording seems like it might add confusion rather than remove it,
because it's not allowing for the fact that log_destination can be
a list. I'd be inclined to write something more along the lines of
"... string that is output at the beginning of each log line that is
sent to stderr, syslog, or eventlog".
regards, tom lane
On Fri, Sep 25, 2026 at 12:36 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Laurenz Albe <laurenz.albe@cybertec.at> writes:
On Fri, 2026-09-25 at 09:32 +0000, PG Doc comments form wrote:
I noticed, that it not documented anywhere what log_line_prefix will
do, if
log_destination = 'jsonlog' (Or CSV). From my tests it seems it is
ignored
and does nothing. But we weren't sure and would be helpful to have this
documented.True; here is a patch.
This wording seems like it might add confusion rather than remove it,
because it's not allowing for the fact that log_destination can be
a list. I'd be inclined to write something more along the lines of
"... string that is output at the beginning of each log line that is
sent to stderr, syslog, or eventlog".regards, tom lane
I agree with Tom
On Fri, 2026-09-25 at 11:36 -0400, Tom Lane wrote:
Laurenz Albe <laurenz.albe@cybertec.at> writes:
On Fri, 2026-09-25 at 09:32 +0000, PG Doc comments form wrote:
I noticed, that it not documented anywhere what log_line_prefix will do, if
log_destination = 'jsonlog' (Or CSV). From my tests it seems it is ignored
and does nothing. But we weren't sure and would be helpful to have this
documented.True; here is a patch.
This wording seems like it might add confusion rather than remove it,
because it's not allowing for the fact that log_destination can be
a list. I'd be inclined to write something more along the lines of
"... string that is output at the beginning of each log line that is
sent to stderr, syslog, or eventlog".
No objection to your wording.
Yours,
Laurenz Albe
Laurenz Albe <laurenz.albe@cybertec.at> writes:
On Fri, 2026-09-25 at 11:36 -0400, Tom Lane wrote:
I'd be inclined to write something more along the lines of
"... string that is output at the beginning of each log line that is
sent to stderr, syslog, or eventlog".
No objection to your wording.
OK, I'll adapt your patch.
regards, tom lane
On Fri, 2026-09-25 at 18:21 -0400, Tom Lane wrote:
Laurenz Albe <laurenz.albe@cybertec.at> writes:
On Fri, 2026-09-25 at 11:36 -0400, Tom Lane wrote:
I'd be inclined to write something more along the lines of
"... string that is output at the beginning of each log line that is
sent to stderr, syslog, or eventlog".No objection to your wording.
OK, I'll adapt your patch.
Thanks for picking this up and improving it.
Yours,
Laurenz Albe