1 Threads_connected
The first thing to pay attention to, to get the value of this variable can not show variables like 'Threads_connected'; but
show status like 'Threads_connected' (the following variable values are also the same);
meaning: the value of the variable indicates how many customers there are currently The extension of connecting to the mysql server
: whether there are too many connections, there is a problem with the network! Especially in the case of pconnect :)
2 Created_tmp_disk_tables
meaning: the number of temporary tables created on the hard disk
extension: If this value is relatively large, then the operation of creating a temporary table (CREATE TEMPORARY TABLE) during query will consume more time
3 Handler_read_first
meaning: the first line of the table index is
extended. If this value changes greatly, it can be considered that there is a problem with the establishment of the table index, and there are more scan operations for the full index.
4 Innodb_buffer_pool_wait_free
意思:This variable indicates the number of times MySQL has to wait for memory pages to be flus
引申:If this variable is high, it suggests that MySQL's memory buffer is incorrectly configured for the amount of writes the server is currently performing.
不了解这个:)
5 Key_reads
means: the number of times the index on the file system is read. Extension
: If this value is too large, you need to consider whether the key cache setting is normal.
6 Max_used_connections
meaning: the maximum number of connections since the restart is
extended: the server load and the number of connections that may need to be adjusted
7 Open_tables
means: the number of currently open tables. Extension
: If this value is very low and the table cache is large, it is no problem to reduce the table cache setting. If this value is large and close to the table cache value, we You need to increase the setting of talbe cache
8 Select_full_join
meaning: the number of full join queries is
extended: the value is too large, and more indexes need to be established to avoid
9 Slow_queries
meaning: the number of slow queries
extension: if it is too large, you should check the log of the slow query and check whether the sql statement is written properly