MySQL Monitoring

Maximum connection

Max connections shows the maximum number of connection attempts to the MySQL server.

Maximum used connections

Max Used Connections displays the maximum number of connections that have been in use simultaneously, since the server started.

Connection usage

Connection Usage denotes the total number of connections with respect to the percentage of maximum connections in the database. This information can be used to tune the database connections for better performance.

Application queries

Application Queries provides the number of statements executed by the server. This variable includes the statements executed within stored programs.

Client queries

Client Queriesdisplays the number of statements executed by the server. This includes only the statements sent to the server by clients and not statements executed within stored programs.

Slow queries

Slow Queries provides the number of queries that have taken more time in seconds than the long_query_time to execute.

Aborted clients

Aborted Clients fetches the number of connections that were aborted because the client died without closing the connection properly.

Aborted connects

Aborted Connects denotes the number of failed attempts to connect to the MySQL server.

Table locks waited

Table Locks Waited is the number of times the requests for table locks had to wait.

Hits

Hits denotes the number of query cache hits.

Free memory

Free Memory fetches the amount of free memory in bytes for the query cache.

Not cached

Not Cached displays the number of non-cached queries.

In cache

In Cache denotes the number of queries registered in the query cache.

Free blocks

Free Blocks displays the number of free memory blocks in the query cache.

Inserts

Inserts fetches the number of queries added to the query cache.

Low memory prunes

Low Memory Prunes denotes the number of queries that were deleted from the query cache because of low memory.

Total blocks

Total Blocks is the total number of blocks in the query cache.

Handler rollback

Handler Rollback denotes the rate of requests to perform an internal rollback operation.

Handler delete

Handler Delete fetches the number of times the rows in a table have been deleted.

Handler read first

Handler Read First displays the number of times the first entry in an index was read.

Handler read key

Handler Read Key provides the number of requests to read a row based on a key.

Handler random next

Handler Random Next fetches the number of requests to read the next row in the data file.

Handler read random

Handler Read Random denotes the number of requests to read a row based on a fixed position.

Handler update

Handler Update fetches the number of requests to update a row in a table.

Handler write

Handler Write displays the number of requests to insert a row in a table.

Writes

Writes provides the total number of writes done in a MySQL server. It is the sum of inserted queries, replaced queries, updated queries, and deleted queries.

Reads

Reads fetches the total number of reads done in a MySQL server. Technically, it is the number of selected queries and number of query cache hits.

Transactions

Transactions denotes the number of transactions.

Full join

Full Join denotes the number of joins that perform table scans because they do not use indexes.

Full range join

Full Range Join displays the number of joins that used a range search on a reference table.

Select range

Select Range shows the number of joins that used ranges on the first table.

Range check

Range Check fetches the number of joins without keys that check for key usage after each row.

Select scan

Select Scan provides the number of joins that did a full scan of the first table.

Maximum execution time exceeded

Maximum Execution Time Exceeded denotes the number of select statements for which the execution timeout exceeded.

Commit

Commit provides the number of commit statements executed.

Commit Select

Commit Select fetches the number of select statements executed.

Commit delete

Commit Delete displays the number of delete statements executed.

Commit delete multi

Commit Delete Multi denotes the number of delete statements that use the multiple-table syntax.

Commit insert

Commit Insert fetches the number of insert statements executed.

Commit insert select

Commit Insert Select displays the number of insert select statements executed.

Commit replace select

Commit Replace Select denotes the number of replace select statements executed.

Commit rollback

Commit Rollback provides the number of rollback statements executed.

Commit update

Commit Update provides the number of update statements executed.

Commit update multi

Commit Update Multi shows the number of update statements that use the multiple-table syntax.

Blocks not flushed

Blocks Not Flushed shows the number of key blocks in the MyISAM key cache that have changed but have not yet been flushed to disk.

Read requests

Read Requests denotes the number of requests to read a key block from the MyISAM key cache.

Key reads

Key Reads displays the number of physical reads of a key block from the disk into the MyISAM key cache.

Write requests

Write Requests fetches the number of requests to write a key block to the MyISAM key cache.

Key writes

Key Writes shows the number of physical writes of a key block from the MyISAM key cache to disk.

Merge passes

Merge Passes denote the number of merge passes that the sort algorithm has had to execute.

Range

Range displays the number of sorts that were done using ranges.

Rows

Rows fetch the number of sorted rows.

Scan

Scan displays the number of sorts that were done by scanning the table.

Connected

Connected shows the number of currently open connections.

Running

Running displays the number of threads that are not sleeping.

Cached

Cached fetches the number of threads in the thread cache.

Created

Created denotes the number of threads created to handle connections.

Received

Received provides the number of bytes received from all clients.

Sent

Sent displays the number of bytes sent to all clients.

Open cache hits

Open Cache Hits displays the number of hits for open tables cache lookups.

Open cache misses

Open Cache Misses fetches the number of misses for open tables cache lookups.

Open cache overflows

Open Cache overflows provides the number of overflows for the open tables cache..

Temporary tables

Temporary Tables displays the number of internal temporary tables created by the server while executing statements.

Disk tables

Disk Tables denotes the number of internal on-disk temporary tables created by the server while executing statements.

Temporary files

Temporary Files shows the number of internal temporary tables created by the server while executing statements.

Buffer pool pages data

Buffer Pool Pages Data displays the number of pages in the InnoDB buffer pool containing data.

Buffer pool pages dirty

Buffer Pool Pages Dirty denotes the current number of dirty pages in the InnoDB buffer pool.

Buffer pool pages free

Buffer Pool Pages Free provides the number of free pages in the InnoDB buffer pool.

Buffer pool pages total

Buffer Pool Pages Total fetches the total number of pages in the InnoDB buffer pool.

Buffer pool wait free

Buffer Pool Wait Free shows the number of times a read or write to InnoDB had to wait as clean pages were not available in the buffer pool.

Log waits

Log Waits displays the number of times the log buffer was too small and a wait was required for it to be flushed before continuing.

Row lock time average

Row Lock Time Avg denotes time to acquire a row lock for InnoDB tables, in milliseconds.

Row lock waits

Row Lock Waits shows the number of times operations on InnoDB tables had to wait for a row lock.

Buffer pool pages flushed

Buffer Pool Pages Flushed fetches the number of requests to flush pages from the InnoDB buffer pool.

Buffer pool read ahead evicted

Buffer Pool Read Ahead Evicted denotes the number of pages that read into the InnoDB buffer pool by the read-ahead background thread that were subsequently evicted without having been accessed by queries.

Buffer pool wait free

Buffer Pool Wait Free shows the number of times a read or write to InnoDB had to wait as clean pages were not available in the buffer pool.

Buffer pool read ahead

Buffer Pool Read Ahead displays the number of pages that read into the InnoDB buffer pool by the read-ahead background thread.

Buffer pool read ahead random

Buffer Pool Read Ahead Random denotes the number of random read-aheads that were initiated by InnoDB.

Buffer pool read requests

Buffer Pool Read Requests fetches the number of logical read requests.

Buffer pool reads

Buffer Pool Reads shows the number of logical reads that InnoDB could not satisfy from the buffer pool, and had to read directly from disk.

Buffer pool write requests

Buffer Pool Write Requests fetches the number of writes in the InnoDB buffer pool.

Data fsync

Data Fsyncdisplays the number of fsync() operations per second.

Data pending fsync

Data Pending Fsyncshows the current number of pending fsync() operations.

Data pending reads

Data Pending Reads provides the current number of pending reads.

Data pending writes

Data Pending Writes denotes the current number of pending writes.

Data reads

Data Reads shows the number of data reads.

Data writes

Data Writes displays the number of data writes.

Data write requests

Data Write Requestss denotes the number of write requests for the InnoDB redo log file.

Log writess

Log Writes depicts the number of physical writes to the InnoDB redo log file.

OS log fsyncs

OS Log Fsyncs provides the number of fsync() writes done to the InnoDB redo log files.

OS log pending fsyncs

OS Log Pending Fsyncs fetches the number of pending fsync() operations for the InnoDB redo log files.

OS log pending writes

Os Log Pending Writes shows the number of pending writes to the InnoDB redo log files.

OS log written

Os Log Written displays the number of bytes written to the InnoDB redo log files.

Pages created

Pages Created denotes the number of pages created by operations on InnoDB tables.

Pages read

Pages Read depicts the number pages read from the InnoDB buffer pool by operations on InnoDB tables.

Pages written

Pages Written fetches the number of pages written by operations on InnoDB tables.

Rows deleted

Rows Deleted provides the number of rows deleted from InnoDB tables.

Rows inserted

Rows Inserted shows the number of rows inserted into InnoDB tables.

Rows read

Rows Read denotes the number of rows read from InnoDB tables.

Rows updated

Rows Updated depicts the number of rows updated in InnoDB tables.

Slave IO state

Slave IO State shows the state of what a thread is doing, such as trying to connect to the source, waiting for events from the source, reconnecting to the source, and so on.

Slave IO running

Slave IO Running displays if the I/O thread has started and connected successfully to the source.

Slave SQL running

Slave Sql Running shows if the SQL thread has started..

Slave running

Slave Running denotes if a slave is running or not.

Connect retry

Connect Retry provides the time between connect retires, in seconds.

Last IO error number

Last IO Errno the error number of the most recent error that caused the I/O thread to stop.

Last SQL error number

Last Sql Errno provides the error number of the most recent error that caused the SQL thread to stop.

Master host

Master Host is the source host that the replica is connected to.

Master retry count

Master Retry Count provides the number of times the replica can attempt to reconnect to the source in the event of a lost connection.

Master server ID

Master Server ID is the server ID value from the source.

Master user

Master User is the user name of the account used to connect to the source.

Relay log space

Relay Log Space is the total combined size of all existing relay log files in bytes.

Seconds behind master

Seconds Behind Master is the difference in seconds between the slave’s clock time and the timestamp of the query, when it was recorded in the master’s binary log.

Skip counter

Skip Counter denotes the number of events from the source that a replica server should skip.