Slow Query Log; Full Table Scans

[MML]

Can I change the value of MONyog.MySQL.GlobalVariables.log_slow_queries? If so, can you please tell me how?

Is the metric displayed in full table scans obtained from system logs? If so, is there a way to view the logs for specific info on which queries are requiring full table scans? If not, how is this metric computed?

Thank you.

[Rohit]

log_slow_queries is a MySQL system variable that defines whether slow queries should be logged. More info is available at http://dev.mysql.com/doc/refman/5.1/en/slow-query-log.html.

MONyog.MySQL.GlobalVariables.* is just a read-only encapsulation of MySQL system variables. So you cannot change the value from MONyog. To change the value of log_slow_queries, you have to change the corresponding my.ini or my.cnf.

The metric displayed for full table scans is obtained by parsing the results from “SHOW GLOBAL STATUS”. You can see the exact formula used for calculation by bringing the mouser over “Percentage of Full Table Scans”. We are using the Handler_* system variables to find out the total number of rows read via full table scans compared to the sum of Handler_* variables which denote all row accesses

We are not parsing the slow query log yet. So MONyog does not give you an interface to identify the slow queries. We are working on that and the next major release will have a slow query log parser.

[MML]

Rohit wrote on May 25 2007, 01:49 AM:

log_slow_queries is a MySQL system variable that defines whether slow queries should be logged. More info is available at http://dev.mysql.com/doc/refman/5.1/en/slow-query-log.html.

MONyog.MySQL.GlobalVariables.* is just a read-only encapsulation of MySQL system variables. So you cannot change the value from MONyog. To change the value of log_slow_queries, you have to change the corresponding my.ini or my.cnf.

The metric displayed for full table scans is obtained by parsing the results from “SHOW GLOBAL STATUS”. You can see the exact formula used for calculation by bringing the mouser over “Percentage of Full Table Scans”. We are using the Handler_* system variables to find out the total number of rows read via full table scans compared to the sum of Handler_* variables which denote all row accesses

We are not parsing the slow query log yet. So MONyog does not give you an interface to identify the slow queries. We are working on that and the next major release will have a slow query log parser.

Thank you.

When I use your formula with the actual Handler_* system variables, though, the results are less than 1/2 of the values shown in the page “% of full table scans”: 31% versus 73.5%

[Author]

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