Long processing time of DELETE FROM plugin_webseer_servers_log

[dipdill]

I have about 36 end points being monitored using webseer.

I started to notice the DELETE FROM plugin_webseer_servers_log WHERE UNIX_TIMESTAMP(lastcheck) < 1504645687 taking minutes to complete in the mysql show processlist;

I made a small change to the query on line 268 of the webseer_process.php. I changed

db_execute('DELETE FROM plugin_webseer_servers_log WHERE UNIX_TIMESTAMP(lastcheck) < ' . (time() - (86400 * 90)));

to

db_execute('DELETE FROM plugin_webseer_servers_log WHERE lastcheck < FROM_UNIXTIME(' . (time() - (86400 * 90)) . ')');

By shifting the unix timestamp to the variable instead of the column mysql can now utilize the indexing on the column.

root@localhost [cacti]> explain DELETE FROM plugin_webseer_servers_log WHERE UNIX_TIMESTAMP(lastcheck) < 1504645687\G 1. row id: 1 select_type: DELETE table: plugin_webseer_servers_log partitions: NULL type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 1025030 filtered: 100.00 Extra: Using where 1 row in set (0.01 sec)

Now after making the change

root@localhost [cacti]> explain DELETE FROM plugin_webseer_servers_log WHERE lastcheck < FROM_UNIXTIME(1504645687)\G 1. row id: 1 select_type: DELETE table: plugin_webseer_servers_log partitions: NULL type: range possible_keys: lastcheck key: lastcheck key_len: 5 ref: const rows: 1 filtered: 100.00 Extra: Using where 1 row in set (0.01 sec)

The process now finishes in under a second on my system. I thought I would share this with you in case you wanted to test or implement it in your next release.

Thanks

[cigamit]

Resolved. Thanks for contributing.