On 2021-02-08 14:26, Fujii Masao wrote:
On 2021/02/08 13:01, Fujii Masao wrote:
On 2021/02/05 8:45, Masahiro Ikeda wrote:
I pgindented the patches.
Thanks for updating the patches!
+ <function>XLogWrite</function>, which nomally called by an
+ <function>issue_xlog_fsync</function>, which nomally called by
an
Typo: "nomally" should be "normally"?
+ <function>XLogFlush</function> request(see <xref
linkend="wal-configuration"/>)
+ <function>XLogFlush</function> request(see <xref
linkend="wal-configuration"/>),
Isn't it better to add a space character just after "request"?
+ INSTR_TIME_SET_CURRENT(duration);
+ INSTR_TIME_SUBTRACT(duration, start);
+ WalStats.m_wal_write_time =
INSTR_TIME_GET_MICROSEC(duration);
If several cycles happen in the do-while loop, m_wal_write_time should
be
updated with the sum of "duration" in those cycles instead of
"duration"
in the last cycle? If yes, "+=" should be used instead of "=" when
updating
m_wal_write_time?
+ INSTR_TIME_SET_CURRENT(duration);
+ INSTR_TIME_SUBTRACT(duration, start);
+ WalStats.m_wal_sync_time =
INSTR_TIME_GET_MICROSEC(duration);
Also "=" should be "+=" in the above?
+ /* Send WAL statistics */
+ pgstat_send_wal();
This may cause overhead in WAL-writing by walwriter because it's called
every cycles even when walwriter needs to write more WAL next cycle
(don't need to sleep on WaitLatch)? If this is right, pgstat_send_wal()
should be called only when WaitLatch() returns with WL_TIMEOUT?
Thanks, I didn't notice that.
I'll fix it.
- <function>XLogFlush</function> request(see <xref
linkend="wal-configuration"/>)
+ <function>XLogFlush</function> request(see <xref
linkend="wal-configuration"/>),
+ or WAL data written out to disk by WAL receiver.
So regarding walreceiver, only wal_write, wal_write_time, wal_sync, and
wal_sync_time are updated even while the other values are not. Isn't
this
confusing to users? If so, what about reporting those walreceiver stats
in
pg_stat_wal_receiver?
OK, I'll add new infrastructure code to interect with wal receiver
and stats collector and show the stats in pg_stat_wal_receiver.
if (endofwal)
+ {
+ /* Send WAL statistics to the stats
collector */
+ pgstat_send_wal();
break;
You added pgstat_send_wal() so that it's called in some cases where
walreceiver exits. But ISTM that there are other walreceiver-exit
cases.
For example, in the case where SIGTERM is received. Instead,
pgstat_send_wal() should be called in WalRcvDie() for those all cases?
Thanks, I forgot the case.
I'll fix it.
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
