function dba_mysql_report_help_full_join in Database Administration 7

Provide tuning advice for high percentage of full joins.

1 call to dba_mysql_report_help_full_join()

dba_mysql_report_output in database/mysql.report.inc

Build mysqlreport output.

File

database/mysql.report.inc, line 540

Provides database driver specific report functions.

Code

function dba_mysql_report_help_full_join() {
  return t("A FULL JOIN is a SELECT query that joins two or more tables together, and then scans the entirety of the joined tables. These types of queries will often show up in your slow query log, and should be optimized by adding a LIMIT to the queries.\n\nAs you are seeing a significant number of joins, you may benefit from increasing the join_buffer_size tunable. Note that this is a per-connection memory allocation, so don't increase the setting too quickly and monitor the change closely to be sure you've not over allocated memory.");
}