Re: Support reset of Shared objects statistics in "pg_stat_reset" function - Mailing list pgsql-hackers
| From | Himanshu Upadhyaya |
|---|---|
| Subject | Re: Support reset of Shared objects statistics in "pg_stat_reset" function |
| Date | |
| Msg-id | CAPF61jDJFWEWRhjrf8+KY_N7kbE=abDhaZy76p=_yOS2cW1rFQ@mail.gmail.com Whole thread Raw |
| In response to | Re: Support reset of Shared objects statistics in "pg_stat_reset" function (Himanshu Upadhyaya <upadhyaya.himanshu@gmail.com>) |
| Responses |
Re: Support reset of Shared objects statistics in "pg_stat_reset" function
|
| List | pgsql-hackers |
Hi Sadhu,
Patch working as expected with shared tables, just one Minor comment on the patch.
+ if (!dbentry)
+ return;
+
+ /*
+ * We simply throw away all the shared table entries by recreating new
+ * hash table for them.
+ */
+ if (dbentry->tables != NULL)
+ hash_destroy(dbentry->tables);
+ if (dbentry->functions != NULL)
+ hash_destroy(dbentry->functions);
+
+ dbentry->tables = NULL;
+ dbentry->functions = NULL;
+
+ /*
+ * This creates empty hash tables for tables and functions.
+ */
+ reset_dbentry_counters(dbentry);
+ return;
+
+ /*
+ * We simply throw away all the shared table entries by recreating new
+ * hash table for them.
+ */
+ if (dbentry->tables != NULL)
+ hash_destroy(dbentry->tables);
+ if (dbentry->functions != NULL)
+ hash_destroy(dbentry->functions);
+
+ dbentry->tables = NULL;
+ dbentry->functions = NULL;
+
+ /*
+ * This creates empty hash tables for tables and functions.
+ */
+ reset_dbentry_counters(dbentry);
We already have the above code for non-shared tables, can we restrict duplicate code?
one solution I can think of, if we can have a list with two elements and iterate each element with
these common steps?
Thanks,
Himanshu
On Fri, Aug 6, 2021 at 5:40 PM Himanshu Upadhyaya <upadhyaya.himanshu@gmail.com> wrote:
Hi Sadhu,> The call to “pg_stat_reset“ does reset all the statistics data for> tables belonging to the current database but does not take care of> shared tables e.g pg_attribute.pg_attribute is not a shared catalog, is the mentioned scenario is also applicable for few others tables?I have just tried it with-out your patch:postgres=# SELECT * FROM pg_statio_all_tables where relid=1249;
relid | schemaname | relname | heap_blks_read | heap_blks_hit | idx_blks_read | idx_blks_hit | toast_blks_read | toast_blks_hit | tidx_blks_read | tidx_blks_hit
-------+------------+--------------+----------------+---------------+---------------+--------------+-----------------+----------------+----------------+---------------
1249 | pg_catalog | pg_attribute | 29 | 522 | 8 | 673 | | | |
(1 row)
postgres=# select pg_stat_reset();
pg_stat_reset
---------------
(1 row)
postgres=# SELECT * FROM pg_statio_all_tables where relid=1249;
relid | schemaname | relname | heap_blks_read | heap_blks_hit | idx_blks_read | idx_blks_hit | toast_blks_read | toast_blks_hit | tidx_blks_read | tidx_blks_hit
-------+------------+--------------+----------------+---------------+---------------+--------------+-----------------+----------------+----------------+---------------
1249 | pg_catalog | pg_attribute | 0 | 0 | 0 | 0 | | | |We are able to reset the stats of pg_attibute without your patch.Thanks,HimanshuOn Fri, Aug 6, 2021 at 1:56 PM Sadhuprasad Patro <b.sadhu@gmail.com> wrote:Hi,
The call to “pg_stat_reset“ does reset all the statistics data for
tables belonging to the current database but does not take care of
shared tables e.g pg_attribute. Similarly to reset the statistics at
table level, the call to “pg_stat_reset_single_table_counters“ does
not take care of shared tables.
When we reset all the statistics using the call “pg_stat_reset”, the
postgres process internally makes calls to “
pgstat_recv_resetcounter“, which resets the statistics of all the
tables of the current database. But not resetting the statistics of
shared objects using database ID as 'InvalidOid'.
The same fix is made in the internal function
“pgstat_recv_resetsinglecounter“ to reset the statistics for the
shared table for the call "pg_stat_reset_single_table_counters".
--
thank u
SADHU PRASAD
EnterpriseDB: http://www.enterprisedb.com
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