Table of Contents
This chapter describes the Oracle Enterprise Manager for MySQL Database metrics.
The following topics are described:
This section describes the All Metrics page of the Oracle Enterprise Manager for MySQL Database.
The following topics are described:
Lists the Admin Statement Activity metrics and provides a brief description of each.
Table 4.1 Admin Statement Activity Metrics
| Name | Description |
|---|---|
| Admin Commands (Delta) | The total number of times a COM_PING, or COM_CHANGE_USER have executed on the protocol. |
| Analyze (Delta) | The total number of ANALYZE TABLE statements executed. |
| Assign To Keycache (Delta) | The total number of CACHE INDEX statements executed. |
| Backup Table (Delta) | The total number of BACKUP TABLE statements executed. |
| Binlog (Delta) | The total number of BINLOG statements executed. |
| Change Master (Delta) | The total number of CHANGE MASTER statements executed. |
| Check (Delta) | The total number of CHECK TABLE statements executed. |
| Checksum (Delta) | The total number of CHECKSUM TABLE statements executed. |
| Flush (Delta) | The total number of FLUSH statements executed. |
| Install Plugin (Delta) | The total number of INSTALL PLUGIN statements executed. |
| Kill (Delta) | The total number of KILL statements executed. |
| Optimize (Delta) | The total number of OPTIMIZE TABLE statements executed. |
| Preload Keys (Delta) | The total number of LOAD INDEX INTO CACHE statements executed. |
| Purge (Delta) | The total number of PURGE BINARY LOGS statements executed. |
| Purge Before Date (Delta) | The total number of PURGE BINARY LOGS BEFORE statements executed. |
| Repair (Delta) | The total number of REPAIR TABLE statements executed. |
| Restore Table (Delta) | The total number of RESTORE TABLE statements executed. |
| Slave Start (Delta) | The total number of START SLAVE statements executed. |
| Slave Stop (Delta) | The total number of STOP SLAVE statements executed. |
| Uninstall Plugin (Delta) | The total number of UNINSTALL PLUGIN statements executed. |
Lists the Audit Log Activity metrics and provides a brief description of each.
Table 4.2 Audit Log Activity Metrics
| Name | Description |
|---|---|
| Current Size (Total) | The size of the current audit log file. The value increases when an event is written to the log and is reset to 0 when the log is rotated. |
| Event Max Drop Size (Total) | The size of the largest dropped event in performance logging mode. |
| Events (Delta) | The number of events handled by the audit log plug-in, whether or not they were written to the log based on filtering policy. |
| Events Buffered (Delta) | The number of audit log events written asynchronously to the audit log buffer when using either the ASYNCHRONOUS or PERFORMANCE audit log strategies. |
| Events Filtered (Delta) | The number of events handled by the audit log plug-in that were filtered (not written to the log) based on filtering policy. |
| Events Lost (Delta) | The number of events lost in performance logging mode because an event was larger than the available audit log buffer space. This value may be useful for assessing how to set audit_log_buffer_size to size the buffer for performance mode. |
| Events Written (Delta) | The number of events written to the audit log. |
| Total Size (Delta) | The total size of events written to all audit log files. Unlike Audit_log_current_size, the value of Audit_log_total_size increases even when the log is rotated. |
| Write Waits (Delta) | The number of times an event had to wait for space in the audit log buffer in asynchronous logging mode. |
| Audit Log Writes Waits (Rate) | The Enterprise Audit Log Plugin Write Waits Rate |
Lists the Binary Logs Summary metrics and provides a brief description of each.
Table 4.3 Binary Logs Summary Metrics
| Name | Description |
|---|---|
| Count (Total) | Number of binlog files. |
| Size (Total) | Total space used by the binlog file. |
| Binary Log File Count | The binary log captures DML, DDL, and security changes that occur and stores these changes in a binary format. The binary log enables replication as well as point-in-time recovery, preventing data loss during a disaster recovery situation. It also enables you to review all alterations made to your database. However, binary logs consume disk space and file system resources, and can be removed from a production server after they are no longer needed by the slaves connecting to this master server, and after they have been backed up. |
| Binary Log Space | The binary log captures DML, DDL, and security changes that occur and stores these changes in a binary format. The binary log enables replication as well as point-in-time recovery, preventing data loss during a disaster recovery situation. It also enables you to review all alterations made to your database. However, binary logs consume disk space and can be removed from a production server after they are no longer needed by the slaves connecting to this master server, and after they have been backed up. |
Lists the Connection Activity metrics and provides a brief description of each.
Table 4.4 Connection Activity Metrics
| Name | Description |
|---|---|
| Aborted Clients (Delta) | The number of connections that were aborted because the client died without closing the connection properly. |
| Aborted Connects (Delta) | The number of failed attempts to connect to the MySQL server. |
| Bytes Received (Delta) | The number of bytes received from all clients. |
| Bytes Sent (Delta) | The number of bytes sent to all clients. |
| Connections (Delta) | The number of connection attempts (successful or not) to the MySQL server. |
| Locked Connects (Delta) | The number of attempts to connect to locked user accounts. |
| Max Execution Time Exceeded (Delta) | The number of SELECT statements for which the execution timeout was exceeded. |
| Max Execution Time Set (Delta) | The number of SELECT statements for which a nonzero execution timeout was set. This includes statements that include a nonzero MAX_EXECUTION_TIME optimizer hint, and statements that include no such hint but execute while the timeout indicated by the max_execution_time system variable is nonzero. |
| Max Execution Time Set Failed (Delta) | The number of SELECT statements for which the attempt to set an execution timeout failed. |
| Max Used Connections (Total) | The maximum number of connections that have been in use simultaneously since the server started. |
| Ongoing Anonymous Transaction Count (Total) | Shows the number of ongoing transactions which have been marked as anonymous. This can be used to ensure that no further transactions are waiting to be processed. |
| Failed Attempted Connections To The Server (Rate) | Excess aborted connection attempts to MySQL may indicate an issue with respect to the server or network, or could be indicative of DoS or password-cracking attempts against the MySQL Server. The aborted-connects count is incremented when: A client does not have privileges to access a database A client uses the wrong password A malformed packet is received The connect_timeout variable is exceeded |
Lists the DDL Statement Activity metrics and provides a brief description of each.
Table 4.5 DDL Statement Activity Metrics
| Name | Description |
|---|---|
| Alter DB (Delta) | The total number of ALTER DATABASE statements executed. |
| Alter DB Upgrade (Delta) | The total number of ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME statements executed. |
| Alter Event (Delta) | The total number of ALTER EVENT statements executed. |
| Alter Function (Delta) | The total number of ALTER FUNCTION statements executed. |
| Alter Procedure (Delta) | The total number of ALTER PROCEDURE statements executed. |
| Alter Server (Delta) | The total number of ALTER SERVER statements executed. |
| Alter Table (Delta) | The total number of ALTER TABLE statements executed. |
| Alter Tablespace (Delta) | The total number of ALTER TABLESPACE statements executed. |
| Create DB (Delta) | The total number of CREATE DATABASE statements executed. |
| Create Event (Delta) | The total number of CREATE EVENT statements executed. |
| Create Function (Delta) | The total number of CREATE FUNCTION statements executed for stored functions. |
| Create Index (Delta) | The total number of CREATE INDEX statements executed. |
| Create Procedure (Delta) | The total number of CREATE PROCEDURE statements executed. |
| Create Server (Delta) | The total number of CREATE SERVER statements executed. |
| Create Table (Delta) | The total number of CREATE TABLE statements executed. |
| Create Trigger (Delta) | The total number of CREATE TRIGGER statements executed. |
| Create UDF (Delta) | The total number of CREATE FUNCTION statements executed for user defined functions. |
| Create User (Delta) | The total number of CREATE USER statements executed. |
| Create View (Delta) | The total number of CREATE VIEW statements executed. |
| Drop DB (Delta) | The total number of DROP DATABASE statements executed. |
| Drop Event (Delta) | The total number of DROP EVENT statements executed. |
| Drop Function (Delta) | The total number of DROP FUNCTION statements executed. |
| Drop Index (Delta) | The total number of DROP INDEX statements executed. |
| Drop Procedure (Delta) | The total number of DROP PROCEDURE statements executed. |
| Drop Server (Delta) | The total number of DROP SERVER statements executed. |
| Drop Table (Delta) | The total number of DROP TABLE statements executed. |
| Drop Trigger (Delta) | The total number of DROP TRIGGER statements executed. |
| Drop User (Delta) | The total number of DROP USER statements executed. |
| Drop View (Delta) | The total number of DROP VIEW statements executed. |
| Grant (Delta) | The total number of GRANT statements executed. |
| Rename Table (Delta) | The total number of RENAME TABLE statements executed. |
| Rename User (Delta) | The total number of RENAME USER statements executed. |
| Truncate (Delta) | The total number of TRUNCATE TABLE statements executed. |
Lists the DML Statement Activity metrics and provides a brief description of each.
Table 4.6 DML Statement Activity Metrics
| Name | Description |
|---|---|
| Call Procedure (Delta) | The total number of CALL statements executed. |
| Change DB (Delta) | The total number of USE statements executed. |
| Dealloc SQL (Delta) | The total number of DEALLOCATE PREPARE statements executed. |
| Delete (Delta) | The total number of DELETE statements executed. |
| Delete Multi (Delta) | The total number of multi-table DELETE statements executed. |
| Do Number (Delta) | The total number of DO statements executed. |
| Empty Query (Delta) | The total number of empty queries executed. |
| Execute SQL (Delta) | The total number of EXECUTE statements executed. |
| Ha Close (Delta) | The total number of HANDLER CLOSE statements executed. |
| Ha Open (Delta) | The total number of HANDLER OPEN statements executed. |
| Ha Read (Delta) | The total number of HANDLER READ statements executed. |
| Help (Delta) | The total number of HELP statements executed. |
| Insert (Delta) | The total number of INSERT statements executed. |
| Insert Select (Delta) | The total number of INSERT ... SELECT statements executed. |
| Load (Delta) | The total number of LOAD DATA INFILE statements executed. |
| Lock Tables (Delta) | The total number of LOCK TABLE statements executed. |
| Prepare SQL (Delta) | The total number of PREPARE statements executed. |
| Replace (Delta) | The total number of REPLACE statements executed. |
| Replace Select (Delta) | The total number of REPLACE ... SELECT statements executed. |
| Reset (Delta) | The total number of RESET statements executed. |
| Resignal (Delta) | The total number of RESIGNAL statements executed. |
| Select (Delta) | The total number of SELECT statements executed. |
| Set Option (Delta) | The total number of SET statements executed. |
| Signal (Delta) | The total number of SIGNAL statements executed. |
| Stmt Close (Delta) | The total number of DEALLOCATE PREPARE statements, ormysql_stmt_close() calls, executed. |
| Stmt Execute (Delta) | The total number of EXECUTE statements, or mysql_stmt_execute() calls, executed. |
| Stmt Fetch (Delta) | The total number of mysql_stmt_fetch() calls executed. |
| Stmt Prepare (Delta) | The total number of PREPARE statements, mysql_stmt_prepare() calls, executed. |
| Stmt Reprepare (Delta) | The total number of re-prepare operations executed for prepared statements. |
| Stmt Reset (Delta) | The total number of mysql_stmt_reset() calls executed. |
| Stmt Send Long Data (Delta) | The total number of mysql_stmt_send_long_data calls executed. |
| Unlock Tables (Delta) | The total number of UNLOCK TABLES statements executed. |
| Update (Delta) | The total number of UPDATE statements executed. |
| Update Multi (Delta) | The total number of multi-table UPDATE statements executed. |
| Prepared Statements Not Being Closed (Rate) | Prepared statements may increase performance in applications that execute similar statements more than once, primarily because the query is parsed only once. Prepared statements can also reduce network traffic because it is only necessary to send the data for the parameters for each execution rather than the whole statement. However, prepared statements take time to prepare and consume memory in the MySQL server until they are closed, so it is important to use them properly. If you are not closing prepared statements when you are done with them, you are needlessly tying up memory that could be put to use in other ways. |
| Prepared Statements Not Being Used Effectively (Rate) | Prepared statements may increase performance in applications that execute similar statements more than once, primarily because the query is parsed only once. Prepared statements can also reduce network traffic because it is only necessary to send the data for the parameters for each execution rather than the whole statement. However, prepared statements take time to prepare and consume memory in the MySQL server until they are closed, so it is important to use them properly. If you are only executing a statement a few times, the overhead of creating a prepared statement may not be worthwhile. |
| All INSERT Statements (Delta) | The sum of INSERT and INSERT ... SELECT statements within the last interval. |
| All UPDATE Statements (Delta) | The sum of single table and multi-table UPDATE statements within the last interval. |
| All REPLACE Statements (Delta) | The sum of REPLACE and REPLACE ... SELECT statements within the last interval. |
| All DELETE statements (Delta) | The sum of single table and multi-table DELETE statements within the last interval. |
Lists the Firewall Activity metrics and provides a brief description of each.
Table 4.7 Firewall Activity Metrics
| Name | Description |
|---|---|
| Access Denied (Delta) | The number of statements rejected by MySQL Enterprise Firewall. |
| Access Granted (Delta) | The number of statements accepted by MySQL Enterprise Firewall. |
| Access Suspicious (Delta) | The number of statements logged by MySQL Enterprise Firewall as suspicious for users who are in DETECTING mode. |
| Cached Entries (Delta) | The number of statements recorded by MySQL Enterprise Firewall, including duplicates. |
Lists the Handler Activity metrics and provides a brief description of each.
Table 4.8 Handler Activity Metrics
| Name | Description |
|---|---|
| Commit (Delta) | The number of internal COMMIT statements. |
| Delete (Delta) | The number of times that rows have been deleted from tables. |
| Discover (Delta) | A counter for the prepare phase of two-phase commit operations. |
| External Lock (Delta) | The server increments this variable for each call to its external_lock() function, which generally occurs at the beginning and end of access to a table instance. |
| MRR Init (Delta) | The number of times the server uses a storage engine's own Multi-Range Read implementation for table access. |
| Prepare (Delta) | The number of times the first entry in an index was read. |
| Read First (Delta) | The number of requests to read a row based on a index key value. If this value is high, it suggests that the server is doing a lot of full index scans. |
| Read Key (Delta) | The number of requests to read the last key in an index. If this value is high, it is a good indication that your tables are properly indexed for your queries. |
| Read Last (Delta) | The number of requests to read the last key in an index. |
| Read Next (Delta) | The number of requests to read the next row in key order. This value is incremented if you are querying an index column with a range constraint or if you are doing an index scan. |
| Read Prev (Delta) | The number of requests to read the previous row in key order. This read method is mainly used to optimize ORDER BY ... DESC. |
| Read Rnd (Delta) | The number of requests to read a row based on a fixed position. This value is high if you are doing a lot of queries that require sorting of the result. |
| Read Rnd Next (Delta) | The number of requests to read the next row in the data file. This value is high if you are doing a lot of table scans. |
| Rollback (Delta) | The number of requests for a storage engine to perform a rollback operation. |
| Savepoint (Delta) | The number of requests for a storage engine to place a savepoint. |
| Savepoint Rollback (Delta) | The number of requests for a storage engine to rollback to a savepoint. |
| Update (Delta) | The number of requests to update a row in a table. |
| Write (Delta) | The number of requests to insert a row in a table. |
| Indexes Not Being Used Efficiently (Rate) | The target server does not appear to be using indexes efficiently. The values of Handler_read_rnd_next and Handler_read_rnd together - which reflect the number of rows read via full table scans - are high compared to the Handler variables which denote index accesses - such as Handler_read_key, Handler_read_next etc. You should examine your tables and queries for proper use of indexes. |
| Rows Read Via Indexes (Delta) | Rows read via the storage engine handler layer that used indexes in the last interval. |
| Rows Read Via Indexes (Per Sec Avg) | Average of rows read per second via the storage engine handler layer that used indexes in the last interval. |
| Rows Read Via Scan (Delta) | Rows read via the storage engine handler layer that used a table scan in the last interval. |
| Rows Read Via Scan (Per Sec Avg) | Average of rows read per second via the storage engine handler layer that used a table scan. |
| Index Usage Ratio (Delta) | The ratio of rows read via indexes vs rows read via table scan in the last interval. |
Lists the InnoDB Activity metrics and provides a brief description of each.
Table 4.9 InnoDB Activity Metrics
| Name | Description |
|---|---|
| Available Undo Logs (Total) | The total number of available InnoDB undo logs. Supplements the innodb_undo_logs system variable, which reports the number of active undo logs. |
| Buffer Pool Bytes Data (Total) | The total number of bytes in the InnoDB buffer pool containing data. The number includes both dirty and clean pages. For more accurate memory usage calculations than with Innodb_buffer_pool_pages_data, when compressed tables cause the buffer pool to hold pages of different sizes. |
| Buffer Pool Bytes Dirty (Total) | The total current number of bytes held in dirty pages in the InnoDB buffer pool. For more accurate memory usage calculations than with Innodb_buffer_pool_pages_dirty, when compressed tables cause the buffer pool to hold pages of different sizes. |
| Buffer Pool Dump Status (Total) | The progress of an operation to record the pages held in the InnoDB buffer pool, triggered by the setting of innodb_buffer_pool_dump_at_shutdown or innodb_buffer_pool_dump_now. |
| Buffer Pool Load Status (Total) | The progress of an operation to warm up the InnoDB buffer pool by reading in a set of pages corresponding to an earlier point in time, triggered by the setting of innodb_buffer_pool_load_at_startup or innodb_buffer_pool_load_now. |
| Buffer Pool Pages Data (Total) | The number of pages containing data (dirty or clean). |
| Buffer Pool Pages Dirty (Total) | The number of pages currently dirty. |
| Buffer Pool Pages Flushed (Delta) | The number of buffer pool page-flush requests. |
| Buffer Pool Pages Free (Total) | The number of free pages. |
| Buffer Pool Pages Latched (Total) | The number of latched pages in InnoDB buffer pool. |
| Buffer Pool Pages Misc (Total) | The number of pages that are busy because they have been allocated for administrative overhead such as row locks or the adaptive hash index. |
| Buffer Pool Pages Total (Total) | The total size of the buffer pool, in pages. |
| Buffer Pool Read Ahead (Delta) | The number of pages read into the InnoDB buffer pool by the read-ahead background thread. |
| Buffer Pool Read Ahead Evicted (Delta) | The number of pages read into the InnoDB buffer pool by the read-ahead background thread that were subsequently evicted without having been accessed by queries. |
| Buffer Pool Read Requests (Delta) | The number of logical read requests InnoDB has done. |
| Buffer Pool Reads (Delta) | The number of logical reads that InnoDB could not satisfy from the buffer pool, and had to read directly from the disk. |
| Buffer Pool Resize Status (Total) | The status of an operation to resize the InnoDB buffer pool dynamically, triggered by setting the innodb_buffer_pool_size parameter dynamically. |
| Buffer Pool Wait Free (Delta) | Normally, writes to the InnoDB buffer pool happen in the background. However, if it is necessary to read or create a page and no clean pages are available, it is also necessary to wait for pages to be flushed first. This counter counts instances of these waits. |
| Buffer Pool Write Requests (Delta) | The number writes done to the InnoDB buffer pool. |
| Data Fsyncs (Delta) | The number of fsync() operations so far. |
| Data Pending Fsyncs (Total) | The current number of pending fsync() operations. |
| Data Pending Reads (Total) | The current number of pending reads. |
| Data Pending Writes (Total) | The current number of pending writes. |
| Data Read (Delta) | The amount of data read since the server was started. |
| Data Reads (Delta) | The total number of data reads. |
| Data Writes (Delta) | The total number of data writes. |
| Data Written (Delta) | The amount of data written so far, in bytes. |
| Dblwr Pages Written (Delta) | The number of pages that have been written for doublewrite operations. |
| Dblwr Writes (Delta) | The number of doublewrite operations that have been performed. |
| Have Atomic Builtins (Total) | Indicates whether the server was built with atomic instructions. |
| Log Waits (Delta) | The number of times that the log buffer was too small and a wait was required for it to be flushed before continuing. |
| Log Write Requests (Delta) | The number of log write requests. |
| Log Writes (Delta) | The number of physical writes to the log file. |
| Os Log Fsyncs (Delta) | The number of fsync() writes done to the log file. |
| Os Log Pending Fsyncs (Total) | The number of pending log file fsync() operations. |
| Os Log Pending Writes (Total) | The number of pending log file writes. |
| Os Log Written (Delta) | The number of bytes written to the log file. |
| Pages Created (Delta) | The number of pages created. |
| Page Size (Total) | The compiled-in InnoDB page size. |
| Pages Read (Delta) | The number of pages read. |
| Pages Written (Delta) | The number of pages written. |
| Row Lock Current Waits (Total) | The number of row locks currently being waited for. |
| Row Lock Time (Delta) | The total time spent in acquiring row locks, in milliseconds. |
| Row Lock Time Avg (Total) | The average time to acquire a row lock, in milliseconds. |
| Row Lock Time Max (Total) | The maximum time to acquire a row lock, in milliseconds. |
| Row Lock Waits (Delta) | The number of times a row lock had to be waited for. |
| Rows Deleted (Delta) | The number of rows deleted from InnoDB tables. |
| Rows Inserted (Delta) | The number of rows inserted into InnoDB tables. |
| Rows Read (Delta) | The number of rows read from InnoDB tables. |
| Rows Updated (Delta) | The number of rows updated in InnoDB tables. |
| Truncated Status Writes (Delta) | The number of times output from the SHOW ENGINE INNODB STATUS statement has been truncated. |
| InnoDB Buffer Cache Sub-Optimal Hit (Rate) | Logical I/O is many times faster than physical I/O, and therefore a DBA should strive to keep physical I/O to a minimum. It is true that logical I/O is not free, and that the DBA should work to keep all I/O to a minimum, but it is best if most data access is performed in memory. When using InnoDB, most data access should occur in RAM, and therefore the InnoDB buffer cache hit rate should be high. |
| InnoDB Buffer Pool Writes Bottleneck (Rate) | For optimal performance, InnoDB should not have to wait before writing pages into the InnoDB buffer pool. |
| InnoDB Log Waits Bottleneck (Rate) | For optimal performance, InnoDB should not have to wait before writing DML activity to the InnoDB log buffer. |
| Buffer Pool Megabytes Data | The total number of megabytes in the InnoDB buffer pool containing data. |
| Buffer Pool Megabytes Dirty | The total current number of megabytes held in dirty pages in the InnoDB buffer pool. |
Lists the InnoDB Adaptive Hash Activity metrics and provides a brief description of each.
Table 4.10 InnoDB Adaptive Hash Activity Metrics
| Name | Description |
|---|---|
| Hash Node Heap (Total) | The total number of (16Kb) pages allocated to the InnoDB adaptive hash index. |
| Hash Searches Per Sec (Total) | The per second average of the searches within InnoDB dissatisfied the adaptive hash index. |
| Hash Table Size (Total) | The total number of array cells allocated to the InnoDB adaptive hash index. |
| Hash Used Cells (Total) | The total number of cells within the hash index array that are in use. This variable is no longer available as of MySQL version 5.1.28. |
| Non Hash Searches Per Sec (Total) | The per second average of the searches within InnoDB not satisfied by the adaptive hash index. |
Lists the InnoDB Bufferpool Activity metrics and provides a brief description of each.
Table 4.11 InnoDB Bufferpool Activity Metrics
| Name | Description |
|---|---|
| Additional Alloc (Total) | The total memory allocated for the InnoDB additional pool in bytes. |
| Compress Seconds (Delta) | The total time in seconds spent compressing InnoDB buffer pool pages. |
| Created Per Sec (Total) | The per second average number of InnoDB buffer pool pages created per second. |
| DB Pages (Total) | The total size in pages of the InnoDB buffer pool LRU list. |
| Dictionary Alloc (Total) | The total memory allocated for the InnoDB data dictionary in bytes. |
| Free Pages (Total) | The total size in pages of the InnoDB buffer pool free list. |
| Hit Rate (Total) | The InnoDB buffer pool page hit rate for pages read from the buffer pool memory vs from disk storage. |
| Io Cur Pages (Total) | The total number of InnoDB buffer pool LRU list pages accessed, for the last second. |
| Io Sum Pages (Total) | The total number of InnoDB buffer pool LRU list pages accessed, for the last 50 seconds. |
| Io Unzip Cur Pages (Total) | The total number of InnoDB buffer pool unzip_LRU list pages accessed, for the last second. |
| Io Unzip Sum Pages (Total) | The total number of Buffer Pool unzip_LRU list pages accessed, for the last 50 seconds. |
| LRU Len (Total) | The total size in pages of the InnoDB buffer pool LRU list. |
| Modified Pages (Total) | The current number of pages modified in the InnoDB buffer pool. |
| Not Young Hit Rate (Total) | The average rate at which InnoDB buffer pool pages have been made not young, for the past 15 seconds. |
| Old DB Pages (Total) | The total size in pages of the InnoDB buffer pool old LRU list. |
| Pages Created (Delta) | The total number of pages created within the InnoDB buffer pool. |
| Pages Evicted No Access Per Sec (Total) | The per second average of the pages evicted without being accessed from the InnoDB buffer pool, for the last 15 seconds. |
| Pages Not Young (Delta) | The total number of pages made not young in the InnoDB buffer pool LRU list. |
| Pages Not Young Per Sec (Total) | The per second average of the pages made not young in the InnoDB buffer pool LRU list, for the last 15 seconds. |
| Pages Random Read Ahead Per Sec (Total) | The per second average of random read ahead operations, for the last 15 seconds. |
| Pages Read (Delta) | The total number of pages read from the InnoDB buffer pool. |
| Pages Read Ahead Per Sec (Total) | The per second average of read ahead operations, for the last 15 seconds. |
| Pages Written (Delta) | The total number of pages written from the InnoDB buffer pool. |
| Pages Young (Delta) | The total number of pages made young in the InnoDB buffer pool LRU list. |
| Pages Young Per Sec (Total) | The per second average of the pages made young in the InnoDB buffer pool LRU list, for the last 15 seconds. |
| Pending Reads (Total) | The number of InnoDB buffer pool pages waiting to be read in to the buffer pool. |
| Pending Writes Flush List (Total) | The number of InnoDB buffer pool pages to be flushed during checkpointing. |
| Pending Writes LRU (Total) | The number of old dirty pages within the InnoDB buffer pool to be written from the bottom of the LRU list. |
| Pending Writes Single Page (Total) | The number of pending independent page writes within the InnoDB buffer pool. |
| Reads Per Sec (Total) | The per second average number of InnoDB buffer pool page reads per second. |
| Size Pages (Total) | The total size in pages allocated to the InnoDB buffer pool. |
| Total Alloc (Total) | The total memory allocated for the InnoDB buffer pool in bytes. |
| Uncompress Seconds (Delta) | The total time in seconds spent uncompressing InnoDB buffer pool pages. |
| Unzip LRU Len (Total) | The total size in pages of the InnoDB buffer pool unzip_LRU list. |
| Written Per Sec (Total) | The per second average number of InnoDB buffer pool page writes per second. |
| Young Hit Rate (Total) | The average rate at which InnoDB buffer pool pages have been made young, for the past 15 seconds. |
Lists the InnoDB Insert Buffer Activity metrics and provides a brief description of each.
Table 4.12 InnoDB Insert Buffer Activity Metrics
| Name | Description |
|---|---|
| Delete Discarded (Delta) | The total number of purge merged operations discarded. |
| Delete Mark Discarded (Delta) | The total number of deleted merged operations discarded. |
| Delete Mark Merges (Delta) | The total number of deleted records merged by change buffering. |
| Delete Merges (Delta) | The total number of times the InnoDB secondary index delete buffer was merged to the InnoDB datafiles. |
| Free List Len (Total) | The number of pages free within the InnoDB secondary index insert buffer. |
| Inserts (Delta) | The total number of inserts to the InnoDB secondary index insert buffer. |
| Inserts Discarded (Delta) | The total number of insert merged operations discarded |
| Merged Recs (Delta) | The total number of records merged from the InnoDB secondary index insert buffer to the InnoDB datafiles. |
| Merges (Delta) | The total number of times the InnoDB secondary index insert buffer was merged to the InnoDB datafiles. |
| Seg Size (Total) | The total size, in pages, of the InnoDB secondary index insert buffer. |
| Size (Total) | The number of pages used within the InnoDB secondary index insert buffer. |
Lists the InnoDB Io Activity metrics and provides a brief description of each.
Table 4.13 InnoDB Io Activity Metrics
| Name | Description |
|---|---|
| Bytes Per Read (Total) | The average bytes per read within InnoDB for the snapshot interval. |
| Open Files (Total) | The number of open files within InnoDB. |
| Os File Fsyncs (Delta) | The total number of fsync() operations performed by InnoDB. |
| Os File Reads (Delta) | The total number of files reads performed by read threads within InnoDB. |
| Os File Writes (Delta) | The total number of file writes performed by write threads within InnoDB. |
| Pending Flushes Bp (Total) | The number of pending buffer flush operations within InnoDB. |
| Pending Flushes Log (Total) | The number of pending redo log flush operations within InnoDB. |
| Pending Ibuf Reads (Total) | The number of pending asynchronous read requests for the secondary index insert buffer within InnoDB. |
| Pending Reads (Total) | The number of pending normal asynchronous IO read requests for data within InnoDB. |
| Pending Redo Log (Total) | The number of pending IO requests (read or write) for therein redo logs. |
| Pending Sync (Total) | The number of pending synchronous IO requests (from user threads rather than background threads) within InnoDB. |
| Pending Writes (Total) | The number of pending normal asynchronous IO write requests for data within InnoDB. |
| Reads Per Sec (Total) | The average number of file reads per second within InnoDB for the snapshot interval. |
| Syncs Per Sec (Total) | The average number of fsync() operations per second within InnoDB for the snapshot interval. |
| Writes Per Sec (Total) | The average number of file writes per second within InnoDB for the snapshot interval. |
Lists the InnoDB Log Activity metrics and provides a brief description of each.
Table 4.14 InnoDB Log Activity Metrics
| Name | Description |
|---|---|
| Checkpoint File (Total) | The low order 32bit value for the redo log sequence number within InnoDB, up to which checkpointing (flushing from the buffer to disk) has completed. This is only available prior to the 5.1.x plug-in and 5.5.x. |
| Checkpoint LSN (Total) | The redo log sequence number within InnoDB, up to which checkpointing (flushing from the buffer to disk) has completed. On versions prior to the 5.1.x plug-in and 5.5.x this is the high order 32bit value, on later versions it is the full 64bit LSN value up to which checkpoints have completed. |
| Flushed File (Total) | The low order 32bit value for the redo log sequence number within InnoDB, up to which the redo log buffer has been flushed to the redo log files. This is only available prior to the 5.1.x plug-in and 5.5.x. |
| Flushed LSN (Total) | The redo log sequence number within InnoDB, up to which the redo log buffer has been flushed to the redo log files. On versions prior to the 5.1.x plug-in and 5.5.x this is the high order 32bit value, on later versions it is the full 64bit LSN value up to which the buffer has been flushed. |
| Io Per Sec (Total) | The per second average number of IO operations for the InnoDB redo logs. |
| Io Total (Delta) | The total number of IO operations for the InnoDB redo logs. |
| Pages Flushed LSN (Total) | The redo log sequence number within InnoDB, up to which the buffer pool has been flushed to the data files. |
| Pending Checkpoint Writes (Total) | The total number of currently pending checkpoint writes within InnoDB. |
| Pending Log Writes (Total) | The total number of writes pending to the InnoDB redo logs. |
| Sequence File (Total) | The low order 32bit value for the redo log sequence number within InnoDB. This is only available prior to the 5.1.x plug-in and 5.5.x. |
| Sequence Number (Total) | The current redo log sequence number within InnoDB. On versions prior to the 5.1.x plug-in and 5.5.x this is the high order 32bit value, on later versions it is the full 64bit LSN value. |
Lists the InnoDB Row Activity metrics and provides a brief description of each.
Table 4.15 InnoDB Row Activity Metrics
| Name | Description |
|---|---|
| Row Queries Inside (Total) | The number of queries executing inside InnoDB. |
| Row Queries Queue (Total) | The number of queries in the queue, waiting to enter InnoDB. |
| Rows Deleted (Delta) | The number of rows deleted from InnoDB tables. |
| Rows Deleted Per Sec (Delta) | The number of rows deleted per second by InnoDB. |
| Rows Inserted (Delta) | The number of rows inserted into InnoDB tables. |
| Rows Inserted Per Sec (Delta) | The number of rows inserted per second by InnoDB. |
| Rows Read (Delta) | The number of rows read from InnoDB tables. |
| Rows Read Per Sec (Delta) | The number of rows read per second by InnoDB. |
| Rows Updated (Delta) | The number of rows updated in InnoDB tables. |
| Rows Updated Per Sec (Delta) | The number of rows updated per second by InnoDB. |
Lists the InnoDB Semaphore Activity metrics and provides a brief description of each.
Table 4.16 InnoDB Semaphore Activity Metrics
| Name | Description |
|---|---|
| Mutex Os Waits (Delta) | The number of InnoDB semaphore/mutex waits yielded to the OS. |
| Mutex Rounds (Delta) | The number of InnoDB semaphore/mutex spin rounds for the internal sync array. |
| Mutex Spin Waits (Delta) | The number of InnoDB semaphore/mutex spin waits for the internal sync array. |
| Os Reservation Count (Delta) | The number of times an InnoDB semaphore/mutex wait was added to the internal sync array. |
| Os Signal Count (Delta) | The number of times an InnoDB thread was signaled using the internal sync array. |
| Rw Excl Os Waits (Delta) | The number of exclusive (write) semaphore waits yielded to the OS by InnoDB. |
| Rw Excl Rounds (Delta) | The number of exclusive (write) semaphore spin rounds within the InnoDB sync array. |
| Rw Excl Spins (Delta) | The number of exclusive (write) semaphore spin waits within the InnoDB sync array. |
| Rw Shared Os Waits (Delta) | The number of shared (read) semaphore waits yielded to the OS by InnoDB. |
| RW Shared Rounds (Delta) | The number of shared (read) semaphore spin rounds within the InnoDB sync array. |
| RW Shared Spins (Delta) | The number of shared (read) semaphore spin waits within the InnoDB sync array. |
| Spins Per Wait Mutex (Delta) | The ratio of InnoDB semaphore/mutex spin rounds to mutex spin waits for the internal sync array. |
| Spins Per Wait RW Excl (Delta) | The ratio of InnoDB exclusive (write) semaphore/mutex spin rounds to spin waits within the internal sync array. |
| Spins Per Wait RW Shared (Delta) | The ratio of InnoDB shared (read) semaphore/mutex spin rounds to spin waits within the internal sync array. |
Lists the InnoDB Thread Activity metrics and provides a brief description of each.
Table 4.17 InnoDB Thread Activity Metrics
| Name | Description |
|---|---|
| Main Thd Log Flush Writes (Delta) | The number of times InnoDB redo logs are written and synced to disk by the master thread. |
| Main Thd Loops Background (Delta) | The number of times the InnoDB main thread did background tasks, such as flushing dirty pages, purging and insert buffer merging, more aggressively when the server is idle. |
| Main Thd Loops Flush (Delta) | The number of times the InnoDB main thread aggressively flushed dirty pages, whilst there was no server activity. |
| Main Thd Loops One Sec (Delta) | The number of times the InnoDB main thread has entered its one second loop structure, to flush dirty pages or drop tables in the background or insert buffer merging. |
| Main Thd Loops Sleeps (Delta) | The number of times the InnoDB main thread was put to sleep, due to no flushing being required within the one second loop. |
| Main Thd Loops Srv Active (Delta) | The number of times the InnoDB main thread has entered its active loop structure. |
| Main Thd Loops Srv Idle (Delta) | The number of times the InnoDB main thread has entered its idle loop structure. |
| Main Thd Loops Srv Shutdown (Delta) | The number of times the InnoDB main thread has entered its shutdown loop structure. |
| Main Thd Loops Ten Sec (Delta) | The number of times the InnoDB main thread has entered its ten second loop structure, to manage purge operations. |
| Main Thd State (Total) | The current state of the main InnoDB thread. |
Lists the InnoDB Transaction Activity metrics and provides a brief description of each.
Table 4.18 InnoDB Transaction Activity Metrics
| Name | Description |
|---|---|
| Committing Count (Total) | The total number of transactions currently committing within InnoDB. |
| Current Lock Wait Count Total (Total) | The total number of rows lock waits within all currently running transactions. |
| Latest Deadlock (Total) | The latest deadlock reported by SHOW ENGINE INNODB STATUS. |
| Latest Foreign Key Error (Total) | The latest foreign key error reported by SHOW ENGINE INNODB STATUS. |
| Lock Memory Bytes Total (Total) | The total number of bytes allocated for lock memory for all currently running transactions. |
| Lock Wait Count (Total) | The total number of transactions waiting for row locks within InnoDB. |
| Rolling Back Count (Total) | The total number of transactions currently rolling back within InnoDB. |
| Rows Locked Total (Total) | The total number of rows locked within all currently running transactions. |
| Rows Modified Total (Total) | The total number of rows modified within all currently running transactions. |
| Running Count (Total) | The total number of transactions currently running within InnoDB. |
| Trx History List Length (Total) | The number of transactions that currently have undo space allocated to them (unpurged). |
| Trx Id Counter1 (Total) | The low order 32bit value for the internal transaction counter within InnoDB. This is only available prior to the 5.1.x plug-in and 5.5.x. |
| Trx Id Counter2 (Total) | The second 32bit internal transaction counter within InnoDB. This is only available prior to the 5.1.x plug-in and 5.5.x. |
| Trx Id Counter Str (Total) | The hexadecimal representation of the internal InnoDB transaction counter, available only on 5.5.x+, or 5.1.x with the plug-in. |
| Trx Purge Done Trx2 (Total) | The transaction counter to which the InnoDB purge process has completed. |
| Trx Total Lock Structs (Total) | The total number of lock structs in use by all transactions within InnoDB. |
Lists the Insert Delayed Activity metrics and provides a brief description of each.
Table 4.19 Insert Delayed Activity Metrics
| Name | Description |
|---|---|
| Errors (Delta) | The number of rows written with INSERT DELAYED for which some error occurred (probably duplicate key). |
| Insert Threads (Total) | The number of INSERT DELAYED handler threads in use. |
| Not Flushed Delayed Rows (Delta) | The number of rows waiting to be written in INSERT DELAYED queues. |
| Writes (Delta) | The number of INSERT DELAYED rows written. |
Lists the Instance Activity metrics and provides a brief description of each.
Table 4.20 Instance Activity Metrics
| Name | Description |
|---|---|
| Flush Commands (Delta) | The number of executed FLUSH statements. |
| Opened Files (Delta) | The number of files that have been opened with my_open() (a mysys library function). |
| Open Files (Total) | The number of files that are open. This count includes regular files opened by the server. It does not include other types of files such as sockets or pipes. |
| Open Streams (Delta) | The number of streams that are open (used mainly for logging). |
| Prepared Stmt Count (Total) | The current number of prepared statements. (The maximum number of statements is given by the max_prepared_stmt_count system variable.). |
| Queries (Delta) | The number of statements executed by the server. This variable includes statements executed within stored programs, unlike the Questions variable. |
| Questions (Delta) | The number of statements executed by the server. This includes only statements sent to the server by clients and not statements executed within stored programs, unlike the Queries variable. |
| Uptime (Total) | The number of seconds that the server has been up. |
| Uptime Since Flush Status (Total) | The number of seconds since the most recent FLUSH STATUS statement. |
| MySQL Server Has Been Restarted | To perform useful work, a database server must be up-and-running continuously. It is normal for a production server to run continuously for weeks, months, or longer. If a server has been restarted recently, it may be the result of planned maintenance, but it may also be due to an unplanned event that should be investigated. |
Lists the NDB Activity metrics and provides a brief description of each.
Table 4.21 NDB Activity Metrics
| Name | Description |
|---|---|
| Conflict Fn Max (Delta) | This variable shows the number of times that a row was not applied on the current SQL node due to 'greatest timestamp wins' conflict resolution since the last time that this mysqld was started. |
| Conflict Fn Old (Delta) | This variable shows the number of times that a row was not applied as the result of 'same timestamp wins' conflict resolution on a given mysqld since the last time it was restarted. |
| Number Of Data Nodes (Total) | If the server is part of a MySQL Cluster, the value of this variable is the number of data nodes in the cluster. |
| Number Of Ready Data Nodes (Total) | The number of running MySQL Cluster data nodes. |
Lists the Performance Schema Activity metrics and provides a brief description of each.
Table 4.22 Performance Schema Activity Metrics
| Name | Description |
|---|---|
| Cond Classes Lost (Delta) | How many instruments of type cond could not be loaded. |
| Cond Instances Lost (Delta) | How many instances of object type cond could not be created. |
| File Classes Lost (Delta) | How many instruments of type file could not be loaded. |
| File Handles Lost (Delta) | How many instances of object type file could not be opened. |
| File Instances Lost (Delta) | How many instances of object type file could not be created. |
| Hosts Lost (Delta) | How many hosts were lost. |
| Index Stat Lost (Delta) | The number of indexes for which statistics were lost. |
| Locker Lost (Delta) | How many events are lost or not recorded. |
| Memory Classes Lost (Delta) | The number of times a memory instrument could not be loaded. |
| Metadata Lock Lost (Delta) | The number of metadata locks that could not be instrumented in the metadata_locks table. |
| Mutex Classes Lost (Delta) | How many instruments of type mutex could not be loaded. |
| Mutex Instances Lost (Delta) | How many instances of object type mutest could not be created. |
| Nested Statement Lost (Delta) | The number of stored program statements for which statistics were lost. |
| Prepared Statements Lost (Delta) | The number of prepared statements that could not be instrumented in the prepared_statements_instances table. |
| Program Lost (Delta) | The number of stored programs for which statistics were lost. |
| Rwlock Classes Lost (Delta) | How many instruments of type rwlock could not be loaded. |
| Rwlock Instances Lost (Delta) | How many instances of object type rwlock could not be created. |
| Table Handles Lost (Delta) | How many instances of object type table could not be opened. |
| Table Instances Lost (Delta) | How many instances of object type table could not be created. |
| Table Lock Stat Lost (Delta) | The number of tables for which lock statistics were lost. |
| Thread Classes Lost (Delta) | How many instruments of type thread could not be loaded. |
| Thread Instances Lost (Delta) | How many instances of object type thread could not be created. |
Lists the Query Cache Activity metrics and provides a brief description of each.
Table 4.23 Query Cache Activity Metrics
| Name | Description |
|---|---|
| Free Blocks (Total) | The number of free memory blocks in the Query Cache. |
| Free Memory (Total) | The amount of free memory (in bytes) for the Query Cache. |
| Hits (Delta) | The number of Query Cache hits. |
| Inserts (Delta) | The number of queries added to the Query Cache. |
| Lowmem Prunes (Delta) | The number of queries that were deleted from the Query Cache because of low memory. |
| Not Cached (Delta) | The number of noncached queries (not cacheable, or not cached due to the query_cache_type setting). |
| Queries In Cache (Total) | The number of queries registered in the Query Cache. |
| Total Blocks (Total) | The total number of blocks in the Query Cache. |
| Average Free Block Size (KB) | The average size in kilobytes of free blocks within the Query Cache. |
| Used Blocks | The number of used memory blocks in the Query Cache. |
| Free Memory (MB) | The amount of free memory in megabytes within the Query Cache. |
Lists the Replication Master Activity metrics and provides a brief description of each.
Table 4.24 Replication Master Activity Metrics
| Name | Description |
|---|---|
| Binlog File (Total) | The name of the current binary log file. |
| Binlog File Position (Total) | The file position of the current binary log file. |
| Cache Disk Use (Delta) | The number of transactions that used the binary log cache but that exceeded the value of binlog_cache_size and used a temporary file to store changes from the transaction. |
| Cache Use (Delta) | The number of transactions that used the binary log cache. |
| Executed Gtid Set (Total) | The latest GTID set within the binary log files. |
| Semi Sync Master Clients (Total) | The number of semisynchronous slaves. |
| Semi Sync Master Net Avg Wait Time (Total) | The average time in microseconds the master waited for a slave reply. |
| Semi Sync Master Net Waits (Delta) | The total number of times the master waited for slave replies. |
| Semi Sync Master Net Wait Time (Delta) | The total time in microseconds the master waited for slave replies. |
| Semi Sync Master No Times (Delta) | The number of times the master turned off semisynchronous replication. |
| Semi Sync Master No Tx (Delta) | The number of commits that were not acknowledged successfully by a slave. |
| Semi Sync Master Status (Total) | Whether semisynchronous replication currently is operational on the master. |
| Semi Sync Master Timefunc Failures (Delta) | The number of times the master failed when calling time functions such as gettimeofday(). |
| Semi Sync Master Tx Avg Wait Time (Delta) | The average time in microseconds the master waited for each transaction. |
| Semi Sync Master Tx Waits (Delta) | The total number of times the master waited for transactions. |
| Semi Sync Master Tx Wait Time (Delta) | The total time in microseconds the master waited for transactions. |
| Semi Sync Master Wait Pos Backtraverse (Delta) | The total number of times the master waited for an event with binary coordinates lower than events waited for previously. |
| Semi Sync Master Wait Sessions (Total) | The number of sessions currently waiting for slave replies. |
| Semi Sync Master Yes Tx (Delta) | The number of commits that were acknowledged successfully by a slave. |
| Show Master Status (Delta) | The total number of SHOW MASTER STATUS statements executed. |
| Show New Master (Delta) | The total number of SHOW NEW MASTER statements executed. |
| Show Slave Hosts (Delta) | The total number of SHOW SLAVE HOSTS statements executed. |
| Status (Total) | The status of fail-safe replication. |
| Exceeded Binary Log Space Limit (Rate) | When binary log usage exceeds the binary log cache memory limits, it is performing excessive disk operations. For optimal performance, transactions that move through the binary log should be contained within the binary log cache. |
Lists the Replication Slave Activity metrics and provides a brief description of each.
Table 4.25 Replication Slave Activity Metrics
| Name | Description |
|---|---|
| Change Master (Delta) | The total number of CHANGE MASTER statements executed. |
| Exec Master Log Pos (Total) | The position in the current master binary file up to which the SQL thread has read and executed. |
| Executed Gtid Set (Total) | The set of global transaction IDs for all received transactions subsequently executed on this slave. Empty if GTIDs are not in use. |
| Heartbeat Period (Total) | The replication heartbeat interval (in seconds) for the slave. |
| Io Running (Total) | Whether the slave I/O thread is started and has connected successfully to the master. |
| Io State (Total) | The current informational state for the slave I/O thread. |
| Last Errno (Total) | The error number of the last error that caused the SQL thread to stop. |
| Last Error (Total) | The error message of the last error that caused the SQL thread to stop. |
| Last Io Errno (Total) | The error number of the last error that caused the I/O thread to stop. |
| Last Io Error (Total) | The error message of the last error that caused the I/O thread to stop. |
| Last SQL Errno (Total) | The error number of the last error that caused the SQL thread to stop. |
| Last SQL Error (Total) | The error message of the last error that caused the SQL thread to stop. |
| Master Log File (Total) | The name of the master binary log file from which the I/O thread is currently reading. |
| Open Temp Tables (Total) | The number of temporary tables that the slave SQL thread currently has open. |
| Read Master Log Pos (Total) | The position in the current master binary log file up to which the I/O thread has read. |
| Received Heartbeats (Delta) | The total number of heartbeats received by the slave since the last time that the slave was restarted or reset, or a CHANGE MASTER TO statement was issued. |
| Relay Log File (Total) | The name of the relay log file from which the SQL thread is currently reading and executing. |
| Relay Log Pos (Total) | The position in the current relay log file up to which the SQL thread has read and executed. |
| Relay Log Space (Total) | The total combined size of all existing relay log files. |
| Relay Master Log File (Total) | The name of the master binary log file containing the most recent event executed by the SQL thread. |
| Retried Transactions (Delta) | The total number of times since startup that the replication slave SQL thread has retried transactions. |
| Retrieved Gtid Set (Total) | The set of global transaction IDs corresponding to all transactions received by this slave. Empty if GTIDs are not in use. |
| Running (Total) | This is ON if this server is a replication slave that is connected to a replication master, and both the I/O and SQL threads are running; otherwise, it is OFF. |
| Seconds Behind Master (Total) | The time difference in seconds between the slave SQL thread and the slave I/O thread, based on the timestamps stored in the relay log events. NULL if the slave SQL thread is not running, or if the slave I/O thread is not running or not connected to the master. |
| Semi Sync Slave Status (Total) | Whether semisynchronous replication currently is operational on the slave. This is ON if the plug-in has been enabled and the slave I/O thread is running, OFF otherwise. |
| Show Slave Status (Delta) | The total number of SHOW SLAVE STATUS statements executed. |
| Skip Counter (Total) | The current value of the sql_slave_skip_counter system variable. |
| Slave Start (Delta) | The total number of START SLAVE statements executed. |
| Slave Stop (Delta) | The total number of STOP SLAVE statements executed. |
| SQL Remaining Delay (Total) | The number of seconds before the slave SQL thread will apply the next event within the relay logs. |
| SQL Running (Total) | Whether the slave SQL thread is started. |
| SQL Running State (Total) | The current informational state for the slave SQL thread. |
| Slave Error: Unknown or Incorrect Time Zone | In order to use time zone names in conjunction with certain statements, functions, and data types, you must configure the server to understand those names by loading information from the operating system's time zone files into a set of tables in the mysql database. However, while the MySQL installation procedure creates those time zone tables, it does not load them; they must be loaded manually after installation. |
| Slave Execution Position Behind Read Position | When a slave receives updates from its master, the I/O thread stores the data in local files known as relay logs. The slave's SQL thread reads the relay logs and executes the updates they contain. If the position from which the SQL thread is reading is way behind the position to which the I/O thread is currently writing, it is a sign that replication is getting behind and results of queries directed to the slave may not reflect the latest changes made on the master. |
| Slave Has Been Stopped | If replication on a slave has been stopped, it means the slave is not retrieving the latest statements from the master and it is not executing those statements on the slave. |
| Slave Has Experienced A Replication Error | When a slave receives updates from its master it must apply those updates locally so the data on the slave matches that on the server. If an error occurs while applying an update on a slave, the data on the slave may not match that on the master and it is an indication that replication may be broken. |
| Slave Has Problem Communicating With Master | Slaves must connect to a master to get the latest data from the master. If they cannot connect, or periodically have trouble connecting, replication may fall behind (i.e. the slave may not have the latest data that was written to the master). |
| Slave Has Stopped Replicating | If neither the slave I/O thread nor the slave SQL threads are running, it means the slave is not getting the latest statements from the master and it is not executing those statements on the slave, and thus replication has stopped entirely. |
| Slave I/O Thread Not Running | The slave I/O thread is the thread that retrieves statements from the master's binary log and records them into the slave's relay log. If this thread isn't running, it means the slave is not able to retrieve the latest data from the master. |
| Slave Relay Log Space | When a slave receives updates from its master, the I/O thread stores the data in local files known as relay logs. The slave's SQL thread reads the relay logs and executes the updates they contain. After the SQL thread has executed all the updates in a relay log, the file is no longer needed and can be deleted to conserve disk space. |
| Slave SQL Thread Not Running | The slave SQL thread is the thread that reads statements from the slave's relay log and executes them to bring the slave in sync with the master. If this thread isn't running, it means the slave is not able to apply the latest changes it has read from the master, and results of queries directed to the slave may not reflect the latest changes made on the master. |
| Slave Seconds Behind Master | If a slave is too far behind the master, results of queries directed to the slave may not reflect the latest changes made on the master. |
| Slave Waiting To Free Relay Log Space | For slaves with limited disk space you can place a limit on how large the replication relay log can grow. When the limit is reached, the I/O thread stops reading binary log events from the master server until the SQL thread has caught up and deleted some unprocessed relay logs. While this protects MySQL from filling up the disk, it means replication is delayed and the slave will fall behind the master. |
Lists the Secure Connections Activity metrics and provides a brief description of each.
Table 4.26 Secure Connections Activity Metrics
| Name | Description |
|---|---|
| Accept Renegotiates (Delta) | The number of negotiates needed to establish the connection. |
| Accepts (Delta) | The number of accepted SSL connections. |
| Callback Cache Hits (Delta) | The number of callback cache hits. |
| Cipher (Total) | The current SSL cipher (empty for non-SSL connections). |
| Cipher List (Total) | The list of possible SSL ciphers. |
| Client Connects (Delta) | The number of SSL connection attempts to an SSL-enabled master. |
| Connect Renegotiates (Delta) | The number of negotiates needed to establish the connection to an SSL-enabled master. |
| Ctx Verify Depth (Total) | The SSL context verification depth --how many certificates in the chain are tested. |
| Ctx Verify Mode (Total) | The SSL context verification mode. |
| Default Timeout (Total) | The default SSL timeout. |
| Finished Accepts (Delta) | The number of successful SSL connections to the server. |
| Finished Connects (Delta) | The number of successful slave connections to an SSL-enabled master. |
| Session Cache Hits (Delta) | The number of SSL session cache hits. |
| Session Cache Misses (Delta) | The number of SSL session cache misses. |
| Session Cache Mode (Total) | The SSL session cache mode. |
| Session Cache Overflows (Delta) | The number of SSL session cache overflows. |
| Session Cache Size (Total) | The SSL session cache size. |
| Session Cache Timeouts (Delta) | The number of SSL session cache timeouts. |
| Sessions Reused (Delta) | How many SSL connections were reused from the cache. |
| Used Session Cache Entries (Delta) | How many SSL session cache entries were used. |
| Verify Depth (Total) | The verification depth for replication SSL connections. |
| Verify Mode (Total) | The verification mode for replication SSL connections. |
| Version (Total) | The SSL version identifier. |
Lists the Show Statement Activity metrics and provides a brief description of each.
Table 4.27 Show Statement Activity Metrics
| Name | Description |
|---|---|
| Show Authors (Delta) | The total number of SHOW AUTHORS statements executed. |
| Show Binlog Events (Delta) | The total number of SHOW BINLOG EVENTS statements executed. |
| Show Binlogs (Delta) | The total number of SHOW BINARY LOGS statements executed. |
| Show Charsets (Delta) | The total number of SHOW CHARACTER SET statements executed. |
| Show Collations (Delta) | The total number of SHOW COLLATION statements executed. |
| Show Column Types (Delta) | The total number of SHOW COLUMNS statements executed. |
| Show Contributors (Delta) | The total number of SHOW CONTRIBUTORS statements executed. |
| Show Create DB (Delta) | The total number of SHOW CREATE DATABASE statements executed. |
| Show Create Event (Delta) | The total number of SHOW CREATE EVENT statements executed. |
| Show Create Func (Delta) | The total number of SHOW CREATE FUNCTION statements executed. |
| Show Create Proc (Delta) | The total number of SHOW CREATE PROCEDURE statements executed. |
| Show Create Table (Delta) | The total number of SHOW CREATE TABLE statements executed. |
| Show Create Trigger (Delta) | The total number of SHOW CREATE TRIGGER statements executed. |
| Show Databases (Delta) | The total number of SHOW DATABASES statements executed. |
| Show Engine Logs (Delta) | The total number of SHOW ENGINE ... LOGS statements executed. |
| Show Engine Mutex (Delta) | The total number of SHOW ENGINE ... MUTEX statements executed. |
| Show Engine Status (Delta) | The total number of SHOW ENGINE ... STATUS statements executed. |
| Show Errors (Delta) | The total number of SHOW ERRORS statements executed. |
| Show Events (Delta) | The total number of SHOW EVENTS statements executed. |
| Show Fields (Delta) | The total number of SHOW FIELDS statements executed. |
| Show Function Code (Delta) | The total number of SHOW FUNCTION CODE statements executed. |
| Show Function Status (Delta) | The total number of SHOW FUNCTION STATUS statements executed. |
| Show Grants (Delta) | The total number of SHOW GRANTS statements executed. |
| Show InnoDB Status (Delta) | The total number of SHOW INNODB STATUS statements executed. |
| Show Keys (Delta) | The total number of SHOW KEYS | INDEX | INDEXES statements executed. |
| Show Logs (Delta) | The total number of SHOW LOGS statements executed. |
| Show Master Status (Delta) | The total number of SHOW MASTER STATUS statements executed. |
| Show New Master (Delta) | The total number of SHOW NEW MASTER statements executed. |
| Show Open Tables (Delta) | The total number of SHOW OPEN TABLES statements executed. |
| Show Plugins (Delta) | The total number of SHOW PLUGINS statements executed. |
| Show Privileges (Delta) | The total number of SHOW PRIVILEGES statements executed. |
| Show Procedure Code (Delta) | The total number of SHOW PROCEDURE CODE statements executed. |
| Show Procedure Status (Delta) | The total number of SHOW PROCEDURE STATUS statements executed. |
| Show Processlist (Delta) | The total number of SHOW PROCESSLIST statements executed. |
| Show Profile (Delta) | The total number of SHOW PROFILE statements executed. |
| Show Profiles (Delta) | The total number of SHOW PROFILES statements executed. |
| Show Relaylog Events (Delta) | The total number of SHOW RELAYLOG EVENTS statements executed. |
| Show Slave Hosts (Delta) | The total number of SHOW SLAVE HOSTS statements executed. |
| Show Slave Status (Delta) | The total number of SHOW SLAVE STATUS statements executed. |
| Show Status (Delta) | The total number of SHOW STATUS statements executed. |
| Show Storage Engines (Delta) | The total number of SHOW STORAGE ENGINES statements executed. |
| Show Tables (Delta) | The total number of SHOW TABLES statements executed. |
| Show Table Status (Delta) | The total number of SHOW TABLE STATUS statements executed. |
| Show Triggers (Delta) | The total number of SHOW TRIGGERS statements executed. |
| Show Variables (Delta) | The total number of SHOW VARIABLES statements executed. |
| Show Warnings (Delta) | The total number of SHOW WARNINGS statements executed. |
Lists the Slow Query Logging Activity metrics and provides a brief description of each.
Table 4.28 Slow Query Logging Activity Metrics
| Name | Description |
|---|---|
| Slow Queries (Delta) | The number of queries that have taken more than long_query_time seconds |
Lists the Table Activity metrics and provides a brief description of each.
Table 4.29 Table Activity Metrics
| Name | Description |
|---|---|
| Created Tmp Disk Tables (Delta) | The total number of temporary tables that were converted to disk based tables, due to exceeding either tmp_table_size or max_heap_table_size. |
| Created Tmp Files (Delta) | How many temporary files mysqld has created. |
| Created Tmp Tables (Delta) | The total number of temporary tables created. |
| Opened Table Definitions (Delta) | The number of .frm files that have been cached. |
| Opened Tables (Delta) | The total number of tables that have been opened. |
| Open Table Definitions (Total) | The number of currently cached .frm files. |
| Open Tables (Total) | The current number of tables held open in the table cache. |
| Sort Merge Passes (Delta) | The number of merge passes that the sort algorithm has had to do. |
| Sort Range (Delta) | The number of sorts that were done using ranges. |
| Sort Rows (Delta) | The number of sorted rows. |
| Sort Scan (Delta) | The number of sorts that were done by scanning the table. |
| Table Locks Immediate (Delta) | The number of times that a request for a table lock could be granted immediately. |
| Table Locks Waited (Delta) | The number of times that a request for a table lock could not be granted immediately and a wait was needed. |
| Temporary Disk Table (Rate) | If the space required to build a temporary table exceeds either tmp_table_size or max_heap_table_size , MySQL creates a disk-based table in the server's tmpdir directory. Also, tables that have TEXT or BLOB columns are automatically placed on disk. For performance reasons it is ideal to have most temporary tables created in memory, leaving exceedingly large temporary tables to be created on disk. |
| Table Cache Not Optimal (Rate) | MySQL is multi-threaded, so there may be many clients issuing queries for a given table simultaneously. To minimize the problem with multiple client threads having different states on the same table, the table is opened independently by each concurrent thread. The table cache is used to cache file descriptors for open tables and there is a single cache shared by all clients. Increasing the size of the table cache allows mysqld to keep more tables open simultaneously by reducing the number of file open and close operations that must be done. If the value of Open_tables is approaching the value of table_cache , this may indicate performance problems. |
| Table Lock Contention (Rate) | Performance can be degraded if the percentage of table operations that have to wait for a lock is high compared to the overall number of locks. This can happen when using a table-level locking storage engine, such as MyISAM, instead of a row-level locking storage engine. |
Lists the Threads Activity metrics and provides a brief description of each.
Table 4.30 Threads Activity Metrics
| Name | Description |
|---|---|
| Cached (Total) | The number of threads in the thread cache. |
| Connected (Total) | The number of currently open connections. |
| Created (Delta) | The number of threads created to handle connections. |
| Running (Total) | The number of threads that are not sleeping. |
| Slow Launch Threads (Delta) | The number of threads that have taken more than slow_launch_time seconds to create. |
| Connection Limit Usage (Rate) | Once the maximum connection limit for the MySQL server has been reached, no other user connections can be established and errors occur on the client side of the application. |
| Thread Pooling Not Enabled | As of MySQL 5.5.16, commercial distributions of MySQL include a thread pool plug-in that provides an alternative thread-handling model designed to reduce overhead and improve performance. It implements a thread pool that increases server performance by efficiently managing statement execution threads for large numbers of client connections. With servers that have many concurrent active connections (generally, more than the number of CPUs within the machine) it can be beneficial for performance to enable the Thread Pool plug-in. This keeps the number of actively executing threads within the server lower, generally leaving less contention for locks and resources, whilst still maintaining very high connection counts from applications. |
| Too Many Concurrent Queries Running | Too many active queries indicates there is a severe load on the server, and may be a sign of lock contention or unoptimized SQL queries. |
Lists the Trx Statement Activity metrics and provides a brief description of each.
Table 4.31 Trx Statement Activity Metrics
| Name | Description |
|---|---|
| Begin (Delta) | The total number of BEGIN | START TRANSACTION statements executed. |
| Commit (Delta) | The total number of COMMIT statements executed. |
| Release Savepoint (Delta) | The total number of RELEASE SAVEPOINT statements executed. |
| Rollback (Delta) | The total number of ROLLBACK statements executed. |
| Rollback To Savepoint (Delta) | The total number of ROLLBACK TO SAVEPOINT statements executed. |
| Savepoint (Delta) | The total number of SAVEPOINT statements executed. |
| XA Commit (Delta) | The total number of XA COMMIT statements executed. |
| XA End (Delta) | The total number of XA END statements executed. |
| XA Prepare (Delta) | The total number of XA PREPARE statements executed. |
| XA Recover (Delta) | The total number of XA RECOVER statements executed. |
| XA Rollback (Delta) | The total number of XA ROLLBACK statements executed. |
| XA Start (Delta) | The total number of XA START statements executed. |
Lists the XA Activity metrics and provides a brief description of each.
Table 4.32 XA Activity Metrics
| Name | Description |
|---|---|
| Log Max Pages Used (Total) | For the memory-mapped implementation of the log that is used by mysqld when it acts as the transaction coordinator for recovery of internal XA transactions, this variable indicates the largest number of pages used for the log since the server started. |
| Log Page Size (Total) | The page size used for the memory-mapped implementation of the XA recovery log. |
| Log Page Waits (Delta) | For the memory-mapped implementation of the recovery log, this variable increments each time the server was not able to commit a transaction and had to wait for a free page in the log. |