At Tue, 1 Feb 2022 10:08:04 +0530, Bharath Rupireddy
<[email protected]> wrote in
> On Tue, Feb 1, 2022 at 9:49 AM Fujii Masao <[email protected]>
> wrote:
> >
> > My previous comment was confusing... Probably I understand why you tried to
> > put this information in checkpoint log message. But I was suggesting to put
> > that information at the end of log message instead of the beginning of it.
> > Because ordinary users would be less interested in this LSN information
> > than other ones like the number of buffers written.
>
> Actually, there's no strong reason to put LSN info at the beginning of
> the message except that LSN/REDO LSN next to the
> checkpoint/restartpoint complete would make the users understand the
> LSN and REDO LSN belong to the checkpoint/restartpoint. Since this
> wasn't a strong reason, I agree to keep it at the end.
>
> Modified in v8.
>
> [1]
> 2022-02-01 04:34:17.657 UTC [3597073] LOG: checkpoint complete: wrote
> 21 buffers (0.1%); 0 WAL file(s) added, 0 removed, 0 recycled;
> write=0.004 s, sync=0.008 s, total=0.031 s; sync files=18,
> longest=0.006 s, average=0.001 s; distance=77 kB, estimate=77 kB;
> lsn=0/14D5AF0, redo lsn=0/14D5AB8
0001 looks good to me.
I tend to agree to 0002.
FWIW, I collected other user-facing usage of "location" as LSN.
xlog.c:5965, 6128:
(errmsg("recovery stopping before WAL location (LSN) \"%X/%X\"",
xlog.c:6718:
(errmsg("control file contains invalid checkpoint location")));
xlog.c:6846:
(errmsg("starting point-in-time recovery to WAL location (LSN) \"%X/%X\"",
xlog.c:6929:
(errmsg("could not find redo location referenced by checkpoint record"),
xlog.c:11298, 11300: (in backup-label)
appendStringInfo(labelfile, "START WAL LOCATION: %X/%X (file %s)\n",
appendStringInfo(labelfile, "CHECKPOINT LOCATION: %X/%X\n",
(and corresponding reader-code)
xlog,c:11791, 11793: (in backup history file)
fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n",
fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n",
(and corresponding reader-code)
repl_scanner.l:151:
yyerror("invalid streaming start location");
pg_proc.dat:
many function descriptions use "location" as LSN.
pg_waldump.c:768,777,886,938,1029,1071,1083:
printf(_(" -e, --end=RECPTR stop reading at WAL location RECPTR\n"));
printf(_(" -s, --start=RECPTR start reading at WAL location RECPTR\n"));
pg_log_error("could not parse end WAL location \"%s\"",
pg_log_error("could not parse start WAL location \"%s\"",
pg_log_error("start WAL location %X/%X is not inside file \"%s\"",
pg_log_error("end WAL location %X/%X is not inside file \"%s\"",
pg_log_error("no start WAL location given");
pg_basebackup.c:476, 615: (confusing with file/directory path..)
pg_log_error("could not parse write-ahead log location \"%s\"",
pg_log_error("could not parse write-ahead log location \"%s\"",
pg_rewind.c:346:
pg_log_info("servers diverged at WAL location %X/%X on timeline %u",
pg_rewind/timeline.c:82:
pg_log_error("Expected a write-ahead log switchpoint location.");
regards.
--
Kyotaro Horiguchi
NTT Open Source Software Center
