Here is an explanation of the values that appear in connection->stat() returned string. It was taken from Ai Hua's April 29, 2006 answer on http://forums.mysql.com/read.php?12,86570,86570.
Uptime--The number of seconds the MySQL server has been running.
Threads--The number of active threads (clients).
Questions--The number of questions (queries) from clients since the server was started.
Slow queries--The number of queries that have taken more than long_query_time seconds.
Opens--The number of tables the server has opened.
Flush tables--The number of flush-*, refresh, and reload commands the server has executed.
Open tables--The number of tables that currently are open.
Queries per second avg--Questions divided by Uptime