On 2021-01-25 10:34, kuroda.hay...@fujitsu.com wrote:
Dear Ikeda-san,
Thank you for updating the patch. This can be applied to master, and
can be used on my RHEL7.
wal_write_time and wal_sync_time increase normally :-).
```
postgres=# select * from pg_stat_wal;
-[ RECORD 1 ]----+------------------------------
wal_records | 121781
wal_fpi | 2287
wal_bytes | 36055146
wal_buffers_full | 799
wal_write | 12770
wal_write_time | 4.469
wal_sync | 11962
wal_sync_time | 132.352
stats_reset | 2021-01-25 00:51:40.674412+00
```
Thanks for checking.
I put a further comment:
```
@@ -3485,7 +3485,53 @@ SELECT pid, wait_event_type, wait_event FROM
pg_stat_activity WHERE wait_event i
<structfield>wal_buffers_full</structfield> <type>bigint</type>
</para>
<para>
- Number of times WAL data was written to disk because WAL
buffers became full
+ Total number of times WAL data was written to disk because WAL
buffers became full
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para
role="column_definition">
+ <structfield>wal_write</structfield> <type>bigint</type>
+ </para>
+ <para>
+ Total number of times WAL data was written to disk
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para
role="column_definition">
+ <structfield>wal_write_time</structfield> <type>double
precision</type>
+ </para>
+ <para>
+ Total amount of time that has been spent in the portion of
+ WAL data was written to disk, in milliseconds
+ (if <xref linkend="guc-track-wal-io-timing"/> is enabled,
otherwise zero).
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para
role="column_definition">
+ <structfield>wal_sync</structfield> <type>bigint</type>
+ </para>
+ <para>
+ Total number of times WAL data was synced to disk
+ (if <xref linkend="guc-wal-sync-method"/> is
<literal>open_datasync</literal> or
+ <literal>open_sync</literal>, this value is zero because WAL
data is synced
+ when to write it).
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para
role="column_definition">
+ <structfield>wal_sync_time</structfield> <type>double
precision</type>
+ </para>
+ <para>
+ Total amount of time that has been spent in the portion of
+ WAL data was synced to disk, in milliseconds
+ (if <xref linkend="guc-track-wal-io-timing"/> is enabled,
otherwise zero.
+ if <xref linkend="guc-wal-sync-method"/> is
<literal>open_datasync</literal> or
+ <literal>open_sync</literal>, this value is zero too because
WAL data is synced
+ when to write it).
</para></entry>
</row>
```
Maybe "Total amount of time" should be used, not "Total number of
time."
Other views use "amount."
Thanks.
I checked columns' descriptions of other views.
There are "Number of xxx", "Total number of xxx", "Total amount of time
that xxx" and "Total time spent xxx".
Since the "time" is used for showing spending time, not count,
I'll change it to "Total number of WAL data written/synced to disk".
Thought?
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
