From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: gkokolatos@protonmail.com
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: shared-memory based stats collector
Date: Sat, 6 Mar 2021 00:32:07 +0900
Message-ID: <a36c4a1a-239e-e050-e7f5-f52c743438c6@oss.nttdata.com> (raw)
In-Reply-To: <20210305.171856.303779618961522117.horikyota.ntt@gmail.com>
References: <20210108.102434.253483097897189339.horikyota.ntt@gmail.com>
<20210114.151425.2043098307171137735.horikyota.ntt@gmail.com>
<20210121.120348.195305077048770640.horikyota.ntt@gmail.com>
<20210305.171856.303779618961522117.horikyota.ntt@gmail.com>
On 2021/03/05 17:18, Kyotaro Horiguchi wrote:
> At Thu, 21 Jan 2021 12:03:48 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in
>> Commit 960869da08 (database statistics) conflicted with this. Rebased.
>>
>> I'm concerned about the behavior that pgstat_update_connstats calls
>> GetCurrentTimestamp() every time stats update happens (with intervals
>> of 10s-60s in this patch). But I didn't change that design since that
>> happens with about 0.5s intervals in master and the rate is largely
>> reduced in this patch, to make this patch simpler.
>
> I stepped on my foot, and another commit coflicted. Just rebased.
Thanks for rebasing the patches!
I think that 0003 patch is self-contained and useful, for example which
enables us to monitor archiver process in pg_stat_activity. So IMO
it's worth pusing 0003 patch firstly.
Here are the review comments for 0003 patch.
+ /* Archiver process's latch */
+ Latch *archiverLatch;
+ /* Current shared estimate of appropriate spins_per_delay value */
The last line in the above seems not necessary.
In proc.h, NUM_AUXILIARY_PROCS needs to be incremented.
/* ----------
* Functions called from postmaster
* ----------
*/
extern int pgarch_start(void);
In pgarch.h, the above is not necessary.
+extern void XLogArchiveWakeup(void);
This seems no longer necessary.
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
These seem also no longer necessary.
PgArchPID = 0;
if (!EXIT_STATUS_0(exitstatus))
- LogChildExit(LOG, _("archiver process"),
- pid, exitstatus);
- if (PgArchStartupAllowed())
- PgArchPID = pgarch_start();
+ HandleChildCrash(pid, exitstatus,
+ _("archiver process"));
I don't think that we should treat non-zero exit condition as a crash,
as before. Otherwise when archive_command fails on a signal,
archiver emits FATAL error and which leads the server restart.
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
*
* The objectives here are to clean up our local state about the child
* process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
}
+ /* Take care of the archiver too */
+ if (pid == PgArchPID)
+ PgArchPID = 0;
+ else if (PgArchPID != 0 && take_action)
+ {
+ ereport(DEBUG2,
+ (errmsg_internal("sending %s to process %d",
+ (SendStop ? "SIGSTOP" : "SIGQUIT"),
+ (int) PgArchPID)));
+ signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+ }
+
Same as above.
In xlogarchive.c, "#include "storage/pmsignal.h"" is no longer necessary.
pgarch_forkexec() should be removed from pgarch.c because it's no longer used.
/* ------------------------------------------------------------
* Public functions called from postmaster follow
* ------------------------------------------------------------
*/
The definition of PgArchiverMain() should be placed just
after the above comment.
exit(0) in PgArchiverMain() should be proc_exit(0)?
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
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To: pgsql-hackers@postgresql.org
Cc: masao.fujii@oss.nttdata.com, horikyota.ntt@gmail.com, gkokolatos@protonmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: shared-memory based stats collector
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