Table of Contents
This chapter describes the Oracle Enterprise Manager for MySQL Database configuration metrics.
The following topics are described:
This section describes the metrics within the Configuration pages of the Oracle Enterprise Manager for MySQL Database.
The following topics are described:
Lists the Audit Log configuration metrics and provides a brief description of each.
Table 5.1 Audit Log Configuration Metrics
| Name | Description |
|---|---|
| Buffer Size (Total) | When the audit log plug-in writes events to the log asynchronously, it uses a buffer to store event contents prior to writing them. This variable controls the size of that buffer, in bytes. The server adjusts the value to a multiple of 4096. The plug-in uses a single buffer, which it allocates when it initializes and removes when it terminates. The plug-in allocates this buffer only if logging is asynchronous. |
| Connection Policy (Total) | The policy controlling how the audit log plug-in writes connection events to its log file. Permitted values: 'ALL' - Log all connection events, 'ERRORS' - Log only failed connection events, 'NONE' - Do not log connection events |
| Enabled State (Total) | This option controls how the server loads the audit_log plug-in at startup. |
| Exclude Accounts (Total) | The accounts for which events should not be logged. The value should be NULL or a string containing a list of one or more comma-separated account names |
| File (Total) | The name of the file to which the audit log plug-in writes events. |
| Flush (Total) | |
| Format (Total) | The audit log file format. Permitted values are OLD and NEW (default OLD). |
| Include Accounts (Total) | The accounts for which events should be logged. The value should be NULL or a string containing a list of one or more comma-separated account names. |
| Policy (Total) | The policy controlling how the audit log plug-in writes events to its log file. Permitted values: 'ALL' - Log all events, 'LOGINS' - Log only login events, 'QUERIES' - Log only query events ,'NONE' - Log nothing (disable the audit stream) |
| Rotate On Size (Total) | If the audit_log_rotate_on_size value is greater than 0, the audit log plug-in closes and reopens its log file if a write to the file causes its size to exceed this value. The original file is renamed to have a timestamp extension. |
| Statement Policy (Total) | The policy controlling how the audit log plug-in writes statement events to its log file. Permitted values: 'ALL' - Log all statement events, 'ERRORS' - Log only failed statement events, 'NONE' - Do not log statement events |
| Strategy (Total) | The logging method used by the audit log plug-in. Permitted values: 'ASYNCHRONOUS' - Log asynchronously, wait for space in output buffer, 'PERFORMANCE' - Log asynchronously, drop request if insufficient space in output buffer, 'SEMISYNCHRONOUS' - Log synchronously, permit caching by operating system, 'SYNCHRONOUS' - Log synchronously, call sync() after each request |
Lists the Binary Logs configuration metrics and provides a brief description of each.
Table 5.2 Binary Logs Configuration Metrics
| Name | Description |
|---|---|
| Binlog Cache Size (Total) | The size of the cache to hold changes to the binary log during a transaction. A binary log cache is allocated for each client if the server supports any transactional storage engines and if the server has the binary log enabled. |
| Binlog Checksum (Total) | Causes the master to write checksums for events written to the binary log. Set to NONE to disable, or the name of the algorithm to be used for generating checksums; currently, only CRC32 checksums are supported. |
| Binlog Direct Non Transactional Updates Enabled (Total) | Causes updates to nontransactional tables to be written directly to the binary log, rather than to the transaction cache. |
| Binlog Do DB (Total) | Whether the MySQL server is currently only filtering binary log updates to specific databases only. |
| Binlog Error Action (Total) | Controls what happens when the server cannot write to the binary log, which can cause the master's log to become inconsistent and replication slaves to lose synchronization. |
| Binlog Format (Total) | This variable sets the binary logging format, and can be any one of STATEMENT, ROW, or MIXED. |
| Binlog Group Commit Sync Delay (Total) | Controls how many microseconds the binary log commit waits before synchronizing the binary log file to disk. By default binlog-group-commit-sync-delay is set to 0, meaning that there is no delay. |
| Binlog Group Commit Sync No Delay Count (Total) | The maximum number of transactions to wait for before aborting the current delay as specified by binlog-group-commit-sync-delay. If binlog-group-commit-sync-delay is set to 0, then this option has no effect. |
| Binlog Gtid Simple Recovery Enabled (Total) | This variable controls how binary log files are iterated during the search for GTIDs when MySQL starts or restarts. |
| Binlog Ignore DB (Total) | Whether the MySQL server is currently ignoring updates to the binary log for specific databases. |
| Binlog Max Flush Queue Time (Total) | How long in microseconds to keep reading transactions from the flush queue before proceeding with the group commit (and syncing the log to disk, if sync_binlog is greater than 0). If the value is 0 (the default), there is no timeout and the server keeps reading new transactions until the queue is empty. |
| Binlog Order Commits Enabled (Total) | If this variable is enabled (the default), transactions are committed in the same order they are written to the binary log. If disabled, transactions may be committed in parallel. In some cases, disabling this variable might produce a performance increment. |
| Binlog Row Image (Total) | When using ROW based or MIXED binary logging, whether to log the full before - pre change - image of the row, or a minimal image of the row if possible (given a unique key on the table), or to only exclude BLOB/TEXT columns from the before image of the row. |
| Binlog Rows Query Log Events Enabled (Total) | Causes the server to write informational log events such as row query log events into its binary log. This information can be used for debugging and related purposes; such as obtaining the original query issued on the master when it cannot be reconstructed from the row updates. |
| Binlog Stmt Cache Size (Total) | Determines the size of the cache for the binary log to hold nontransactional statements issued during a transaction. Separate binary log transaction and statement caches are allocated for each client if the server supports any transactional storage engines and if the server has the binary log enabled. |
| Binlog Trusts Function Creators Enabled (Total) | This variable applies when binary logging is enabled and controls whether stored function creators can be trusted not to create stored functions that will cause unsafe events to be written to the binary log. |
| Expire Logs Days (Total) | The number of days for automatic binary log file removal. |
| Log Bin Basename (Total) | Holds the name and complete path to the binary log file. |
| Log Bin Enabled (Total) | Whether the binary log is enabled. |
| Log Bin Index (Total) | The index file for binary log file names. |
| Log Bin Use V1 Row Events Enabled (Total) | Version 2 binary log row events are used by default beginning with MySQL Cluster NDB 7.2.1; however, Version 2 events cannot be read by previous MySQL Cluster releases. Setting --log-bin-use-v1-row-events to 1 causes mysqld to write the binary log using Version 1 logging events, which is the only version of binary log events used in previous releases, and thus produce binary logs that can be read by older slaves. |
| Max Binlog Cache Size (Total) | If a transaction requires more than this many bytes of memory, the server generates a Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage error. |
| Max Binlog Size (Total) | If a write to the binary log causes the current log file size to exceed the value of this variable, the server rotates the binary logs. |
| Max Binlog Stmt Cache Size (Total) | If nontransactional statements within a transaction require more than this many bytes of memory, the server generates an error. max_binlog_stmt_cache_size sets the size for the statement cache only; the upper limit for the transaction cache is governed exclusively by the max_binlog_cache_size system variable. |
| SQL Log Bin Enabled (Total) | If disabled, no logging is done to the binary log for the client. |
| Sync Binlog (Total) | If the value of this variable is greater than 0, the MySQL server synchronizes its binary log to disk (using fdatasync()) after every sync_binlog writes to the binary log. |
Lists the Capabilities configuration metrics and provides a brief description of each.
Table 5.3 Capabilities Configuration Metrics
| Name | Description |
|---|---|
| Compress Enabled (Total) | True if the zlib compression library is available to the server, false if not. |
| Crypt Enabled (Total) | True if the crypt() system call is available to the server, false if not. |
| Csv Enabled (Total) | True if mysqld supports CSV tables, false if not. |
| Dynamic Loading Enabled (Total) | True if mysqld supports dynamic loading of plugins, false if not. |
| Event Scheduler Enabled (Total) | Enable or disable, and start or stop, the event scheduler. |
| Geometry Types Enabled (Total) | True if the server supports spatial data types, false if not. |
| InnoDB Enabled (Total) | True if mysqld supports InnoDB tables. false if --skip-innodb is used. |
| Ndbcluster Enabled (Total) | True if mysqld supports NDBCLUSTER tables, false if --skip-ndbcluster is used. |
| OpenSSL Enabled (Total) | True if mysqld supports SSL connections, false if not. |
| Partitioning Enabled (Total) | True if mysqld supports partitioning. |
| Profiling Enabled (Total) | True if statement profiling is enabled, false if not. |
| Query Cache Enabled (Total) | True if mysqld supports the query cache, false if not. |
| Rtree Keys Enabled (Total) | True if RTREE indexes are available, false if not. |
| SSL Enabled (Total) | True if mysqld supports SSL connections, false if not. |
| Statement Timeout Enabled (Total) | True if the statement timeout feature is available on this platform and the module is initialized, false if not. |
| Symlink Enabled (Total) | True if symbolic link support is enabled, false if not. |
Lists the Character Set configuration metrics and provides a brief description of each.
Table 5.4 Character Set Configuration Metrics
| Name | Description |
|---|---|
| Client (Total) | The character set for statements that arrive from the client. |
| Connection (Total) | The character set used for literals that do not have a character set introducer and for number-to-string conversion. |
| Database (Total) | The character set used by the default database. |
| Directory (Total) | The directory where character sets are installed. |
| Filesystem (Total) | The file system character set. |
| Results (Total) | The character set used for returning query results such as result sets or error messages to the client. |
| Server Default (Total) | The server's default character set. |
| System (Total) | The character set used by the server for storing identifiers. |
Lists the Collation configuration metrics and provides a brief description of each.
Table 5.5 Collation Configuration Metrics
| Name | Description |
|---|---|
| Connection (Total) | The collation of the connection character set. |
| Database (Total) | The collation used by the default database. |
| Server Default (Total) | The server's default collation. |
Lists the Connection configuration metrics and provides a brief description of each.
Table 5.6 Connection Configuration Metrics
| Name | Description |
|---|---|
| Back Log (Total) | The number of outstanding connection requests MySQL can have. |
| Connect Timeout (Total) | The number of seconds that the MySQL server waits for a connect packet before responding with 'Bad handshake'. |
| Init Connect (Total) | A string to be executed by the server for each client that connects. |
| Interactive Timeout (Total) | The number of seconds the server waits for activity on an interactive connection before closing it. |
| Max Connect Errors (Total) | If there are more than this number of interrupted connections from a host, that host is blocked from further connections. |
| Max Connections (Total) | The maximum permitted number of simultaneous client connections. |
| Max User Connections (Total) | The maximum number of simultaneous connections permitted to any given MySQL user account. |
| Net Buffer Length (Total) | Each client thread is associated with a connection buffer and result buffer. Both begin with a size given by net_buffer_length but are dynamically enlarged up to max_allowed_packet bytes as needed. |
| Net Read Timeout (Total) | The number of seconds to wait for more data from a connection before aborting the read. |
| Net Retry Count (Total) | If a read on a communication port is interrupted, retry this many times before giving up. |
| Net Write Timeout (Total) | The number of seconds to wait for a block to be written to a connection before aborting the write. |
| Offline Mode Enabled (Total) | Whether the server is in offline mode, where connected client users who do not have the SUPER privilege are disconnected on the next request. |
| Session Track Gtids (Total) | Enables a tracker for capturing GTIDs and returning them in the OK packet. |
| Session Track Schema Enabled (Total) | The server can track changes to the default schema (database) name within the current session and make this information available to the client when changes occur. This variable controls whether notification occurs. |
| Session Track State Change Enabled (Total) | Whether the server tracks changes to the session state and notifies the client when changes to state information occur. |
| Session Track System Variables (Total) | The server can track changes to the session system variables and make this information available to the client when changes occur. The variable value is a comma-separated list of variables for which to track changes. By default, notification is enabled for time_zone, autocommit, character_set_client, character_set_results, and character_set_connection. |
| Skip Name Resolve Enabled (Total) | Whether MySQL should resolve host names when checking client connections. |
| Wait Timeout (Total) | The number of seconds the server waits for activity on a noninteractive connection before closing it. |
Lists the Connection Buffers configuration metrics and provides a brief description of each.
Table 5.7 Connection Buffers Configuration Metrics
| Name | Description |
|---|---|
| Bulk Insert Buffer Size (Total) | Limits the size (in bytes) of the special tree-like cache MyISAM uses to make bulk inserts faster for INSERT ... SELECT, INSERT ... VALUES (...), (...), ..., and LOAD DATA INFILE, when adding data to nonempty tables, per thread. |
| Join Buffer Size (Total) | The minimum size (in bytes) of the buffer that is used for plain index scans, range index scans, and joins that do not use indexes and thus perform full table scans. |
| Max Allowed Packet (Total) | The maximum size (in bytes) of one packet or any generated / intermediate string from connections to the MySQL server. |
| Net Buffer Length (Total) | Each client connection is associated with a connection buffer and result buffer. Both begin with a size given by net_buffer_length (in bytes) but are dynamically enlarged up to max_allowed_packet bytes as needed. |
| Preload Buffer Size (Total) | The size of the buffer that is allocated when preloading indexes. |
| Query Alloc Block Size (Total) | The allocation size of memory blocks that are allocated for objects created during statement parsing and execution. If you have problems with memory fragmentation, it might help to increase this parameter. |
| Query Prealloc Size (Total) | The size of the persistent buffer used for statement parsing and execution. |
| Read Buffer Size (Total) | Each thread that does a sequential scan allocates a buffer of this size (in bytes) for each table it scans. |
| Read Rnd Buffer Size (Total) | The size (in bytes) for reading rows in sorted order following a key-sorting operation, to avoid disk seeks. |
| Sort Buffer Size (Total) | Each session that needs to do a sort allocates a buffer of this size (in bytes). |
| Stored Program Cache (Total) | Sets a soft upper limit for the number of cached stored routines per connection. The value of this variable is specified in terms of the number of stored routines held in each of the two caches maintained by the MySQL Server for, respectively, stored procedures and stored functions. |
| Thread Stack (Total) | The stack size for each connection thread. |
| Transaction Alloc Block Size (Total) | The size (in bytes) by which to increase the per-transaction memory pool use for connection transactions. |
| Transaction Prealloc Size (Total) | The initial size (in bytes) of the per-transaction memory pool from which various transaction-related allocations take memory. |
Lists the Environment configuration metrics and provides a brief description of each.
Table 5.8 Environment Configuration Metrics
| Name | Description |
|---|---|
| Basedir (Total) | The MySQL installation base directory. |
| Core File Enabled (Total) | Whether to write a core file if the server crashes. |
| Datadir (Total) | The MySQL data directory. |
| Hostname (Total) | The server sets this variable to the server host name at startup. |
| Ignore DB Dirs (Total) | A comma-separated list of names that are not considered as database directories in the data directory. |
| Init File (Total) | The name of the file specified with the --init-file option when you start the server. |
| Keep Files On Create Enabled (Total) | If a MyISAM table is created with a DATA DIRECTORY or INDEX DIRECTORY option and an existing .MYD or .MYI file is found, MyISAM always returns an error. |
| Large Files Support Enabled (Total) | Whether mysqld was compiled with options for large file support. |
| Large Pages Enabled (Total) | Whether large page support is enabled (via the --large-pages option). |
| Large Page Size (Total) | If large page support is enabled, this shows the size of memory pages. |
| Locked In Memory Enabled (Total) | Whether mysqld was locked in memory with --memlock. |
| Lower Case File System Enabled (Total) | Whether the file system where the data directory is located is case sensitive or not. |
| New Mode Enabled (Total) | This variable was used in MySQL 4.0 to turn on some 4.1 behaviors, and is retained for backward compatibility. |
| Old Mode Enabled (Total) | When enabled, changes the default scope of index hints to that used prior to MySQL 5.1.17. That is, index hints with no FOR clause apply only to how indexes are used for row retrieval and not to resolution of ORDER BY or GROUP BY clauses. |
| Open Files Limit (Total) | The maximum number of file descriptors available to mysqld. |
| PID File (Total) | The path name of the process ID file. |
| Plugin Dir (Total) | The path name of the plug-in directory. |
| Show Compatibility56 Enabled (Total) | As of MySQL 5.7.6, system and status variable information is available in Performance Schema tables. When show_compatibility_56 is ON, compatibility is enabled. Older variable information sources (SHOW statements, INFORMATION_SCHEMA tables) produce the same output as in MySQL 5.6. Newer information sources (Performance Schema tables) produce no output. When show_compatibility_56 is OFF, compatibility is disabled. The INFORMATION_SCHEMA tables produce no output. The SHOW statements and the Performance Schema tables do produce output. The INFORMATION_SCHEMA tables produce no output because the Performance Schema tables are intended to replace them. The INFORMATION_SCHEMA tables are deprecated as of MySQL 5.7.6 and will be removed in a future MySQL release. |
| Show Old Temporals Enabled (Total) | Whether SHOW CREATE TABLE output includes comments to flag temporal columns found to be in pre-5.6.4 format (TIME, DATETIME, and TIMESTAMP columns without support for fractional seconds precision). |
| Skip External Locking Enabled (Total) | This is OFF if mysqld uses external locking, ON if external locking is disabled. |
| SQL Mode (Total) | SQL modes define what SQL syntax MySQL should support and what kind of data validation checks it should perform. |
| Tmpdir (Total) | The path of the directory to use for creating temporary files. |
Lists the Firewall configuration metrics and provides a brief description of each.
Table 5.9 Firewall Configuration Metrics
| Name | Description |
|---|---|
| Max Query Size (Total) | The maximum size of a normalized statement that can be inserted in the MySQL Enterprise Firewall cache. Normalized statements longer than this size are truncated. Truncated statements are discarded if the firewall mode for the current user is RECORDING and rejected if the mode is PROTECTING. |
| Mode (Total) | Whether MySQL Enterprise Firewall is enabled (the default) or disabled. |
| Trace (Total) | Whether the MySQL Enterprise Firewall trace is enabled or disabled (the default). This system variable is for internal use. When enabled, the firewall writes a file named firewall_trace.txt in the data directory. |
Lists the Host Cache configuration metrics and provides a brief description of each.
Table 5.10 Host Cache Configuration Metrics
| Name | Description |
|---|---|
| Host Cache Size (Total) | The size of the internal host cache. Setting the size to 0 disables the host cache. Changing the cache size at runtime implicitly causes a FLUSH HOSTS operation to clear the host cache and truncate the host_cache table. |
Lists the InnoDB Configuration configuration metrics and provides a brief description of each.
Table 5.11 InnoDB Configuration Configuration Metrics
| Name | Description |
|---|---|
| Adaptive Flushing Enabled (Total) | Whether an heuristic to determine when to flush dirty pages in the buffer pool should be used. |
| Adaptive Flushing LWM (Total) | Low water mark representing percentage of redo log capacity at which adaptive flushing is enabled. |
| Adaptive Hash Index Enabled (Total) | Whether InnoDB adaptive hash indexes are enabled or disabled. |
| Adaptive Max Sleep Delay (Total) | Allows InnoDB to automatically adjust the value of innodb_thread_sleep_delay up or down according to the current workload. |
| Additional MEM Pool Size (Total) | The size in bytes of a memory pool InnoDB uses to store data dictionary information and other internal data structures. |
| Autoextend Increment (Total) | The increment size (in MB) for extending the size of an auto-extending shared tablespace file when it becomes full. |
| Autoinc Lock Mode (Total) | The locking mode to use for generating auto-increment values. |
| Buffer Pool Chunk Size (Total) | Defines the chunk size for online InnoDB buffer pool resizing operations. |
| Buffer Pool Dump At Shutdown Enabled (Total) | Whether to record the pages cached in the InnoDB buffer pool when the MySQL server is shut down, to shorten the warmup process at the next restart. |
| Buffer Pool Dump Now Enabled (Total) | Immediately records the pages cached in the InnoDB buffer pool. |
| Buffer Pool Dump Pct (Total) | Specifies the percentage of the most recently used pages for each buffer pool to read out and dump. |
| Buffer Pool Filename (Total) | Specifies the file that holds the list of page numbers produced by innodb_buffer_pool_dump_at_shutdown or innodb_buffer_pool_dump_now. |
| Buffer Pool Instances (Total) | The number of regions that the InnoDB buffer pool is divided into. For systems with buffer pools in the multi-gigabyte range, dividing the buffer pool into separate instances can improve concurrency, by reducing contention as different threads read and write to cached pages. |
| Buffer Pool Load At Startup Enabled (Total) | Specifies that, on MySQL server startup, the InnoDB buffer pool is automatically warmed up by loading the same pages it held at an earlier time. |
| Buffer Pool Load Now Enabled (Total) | Immediately warms up the InnoDB buffer pool by loading a set of data pages, without waiting for a server restart. |
| Buffer Pool Load On Abort Enabled (Total) | Interrupts the process of restoring InnoDB buffer pool contents triggered by innodb_buffer_pool_load_at_startup or innodb_buffer_pool_load_now. |
| Buffer Pool Size (Total) | The size in bytes of the memory buffer InnoDB uses to cache data and indexes of its tables. |
| Change Buffering (Total) | Whether InnoDB performs change buffering, an optimization that delays write operations to secondary indexes so that the I/O operations can be performed sequentially. |
| Change Buffer Max Size (Total) | Maximum size for the InnoDB change buffer, as a percentage of the total size of the buffer pool. You might increase this value for a MySQL server with heavy insert, update, and delete activity, or decrease it for a MySQL server with unchanging data used for reporting. |
| Checksum Algorithm (Total) | Specifies how to generate and verify the checksum stored in each disk block of each InnoDB tablespace. Replaces the innodb_checksums option. |
| Checksums Enabled (Total) | Whether InnoDB uses checksum validation on all pages read from the disk to ensure extra fault tolerance against broken hardware or data files. |
| Commit Concurrency (Total) | The number of threads that can commit at the same time within InnoDB. |
| Compression Failure Threshold Pct (Total) | Sets the cutoff point at which MySQL begins adding padding within compressed pages to avoid expensive compression failures. A value of zero disables the mechanism that monitors compression efficiency and dynamically adjusts the padding amount. |
| Compression Level (Total) | Specifies the level of zlib compression to use for InnoDB compressed tables and indexes. |
| Compression Pad Pct Max (Total) | Specifies the maximum percentage that can be reserved as free space within each compressed page, allowing room to reorganize the data and modification log within the page when a compressed table or index is updated and the data might be recompressed. |
| Compression Per Index Enabled (Total) | Enables per-index compression-related statistics in the INFORMATION_SCHEMA.INNODB_CMP_PER_INDEX table. |
| Concurrency Tickets (Total) | The number of threads that can enter InnoDB concurrently. |
| Data File Path (Total) | The paths to individual InnoDB data files and their sizes. |
| Data Home Dir (Total) | The common part of the directory path for all InnoDB data files in the shared tablespace. |
| Disable Sort File Cache Enabled (Total) | Disables caching of sort files on Linux and Solaris when creating indexes. |
| Doublewrite Enabled (Total) | Whether to enabled doublewrite buffering (writing the data twice, to a buffer then the data file) within InnoDB. |
| Fast Shutdown (Total) | Speeds up the shutdown process of the InnoDB storage engine. |
| File Format (Total) | The file format to use for new InnoDB tables. |
| File Format Check Enabled (Total) | Whether InnoDB checks the file format tag in the shared tablespace on server start for version compatibility. |
| File Format Max (Total) | The file format tag InnoDB sets in the shared tablespace (for example, Antelope or Barracuda). |
| File Per Table Enabled (Total) | Whether each InnoDB table should be stored in an .ibd file in the database directory instead of the central tablespace (ibdata*) files. |
| Fill Factor (Total) | Defines the percentage of space on each B-tree page that is filled during a sorted index build, with the remaining space reserved for future index growth. |
| Flushing Avg Loops (Total) | Number of iterations for which InnoDB keeps the previously calculated snapshot of the flushing state, controlling how quickly adaptive flushing responds to changing workloads. |
| Flush Log At Timeout (Total) | Write and flush the logs every N seconds. This setting has an effect only when innodb_flush_log_at_trx_commit has a value of 2. |
| Flush Log At Trx Commit (Total) | Defines how InnoDB should flush it's transaction redo log buffer and files. |
| Flush Method (Total) | Defines how InnoDB flushes both data and redo log files to disk. |
| Flush Neighbors Enabled (Total) | Specifies whether flushing a page from the InnoDB buffer pool also flushes other dirty pages in the same extent. |
| Force Load Corrupted Enabled (Total) | Lets InnoDB load tables at startup that are marked as corrupted. Use only during troubleshooting, to recover data that is otherwise inaccessible. When troubleshooting is complete, turn this setting back off and restart the server. |
| Force Recovery (Total) | The crash recovery mode that InnoDB should be started with, should not be used in normal operations. |
| Foreign Key Checks Enabled (Total) | Whether foreign key constraint checking is enabled/disabled globally. |
| Ignore Builtin InnoDB Enabled (Total) | Whether the server was started with the --ignore-builtin-innodb option. |
| Io Capacity (Total) | The maximum number of I/O operations per second that InnoDB will perform. |
| Io Capacity Max (Total) | The limit up to which InnoDB is allowed to extend the innodb_io_capacity setting, per buffer pool instance, in case of emergency. Its default value is twice the default value of innodb_io_capacity, with a lower limit of 2000. |
| Large Prefix Enabled (Total) | Enable this option to allow index key prefixes longer than 767 bytes (up to 3072 bytes), for InnoDB tables that use the DYNAMIC and COMPRESSED row formats. |
| Locks Unsafe For Binlog Enabled (Total) | Affects how InnoDB uses gap locking for searches and index scans. |
| Lock Wait Timeout (Total) | The timeout in seconds an InnoDB transaction may wait for a row lock before giving up. |
| Log Buffer Size (Total) | The size in bytes of the buffer that InnoDB uses to write to the log files on disk. |
| Log Compressed Pages Enabled (Total) | Whether to log the compressed version of pages to the redo logs or not. |
| Log Files In Group (Total) | The number of redo log files in the InnoDB redo log group. |
| Log File Size (Total) | The size in bytes of each InnoDB redo log file in a redo log group. |
| Log Group Home Dir (Total) | The directory path to the InnoDB redo log files. |
| Log Write Ahead Size (Total) | The write-ahead block size for the redo log, in bytes. |
| LRU Scan Depth (Total) | Specifies, per buffer pool instance, how far down the buffer pool LRU list the page_cleaner thread scans looking for dirty pages to flush. |
| Max Dirty Pages Pct (Total) | InnoDB tries to write pages from the buffer pool so that the percentage of dirty (not yet written) pages will not exceed this value. |
| Max Dirty Pages Pct LWM (Total) | Low water mark representing percentage of dirty pages where preflushing is enabled to control the dirty page ratio. |
| Max Purge Lag (Total) | How long InnoDB should delay INSERT, UPDATE, and DELETE operations when purge operations are lagging. |
| Max Purge Lag Delay (Total) | Specifies the maximum delay in milliseconds for the delay imposed by the innodb_max_purge_lag configuration option. |
| Max Undo Log Size (Total) | Defines a threshold size for undo tablespaces. |
| Mirrored Log Groups (Total) | The number of identical copies of log groups to keep for the database. |
| Monitor Disable (Total) | Turns off one or more counters in the information_schema.innodb_metrics table. |
| Monitor Enable (Total) | Turns on one or more counters in the information_schema.innodb_metrics table. |
| Monitor Reset (Total) | Resets to zero the count value for one or more counters in the information_schema.innodb_metrics table. |
| Monitor Reset All (Total) | Resets all values (minimum, maximum, and so on) for one or more counters in the information_schema.innodb_metrics table. |
| Old Blocks Pct (Total) | Specifies the approximate percentage of the InnoDB buffer pool used for the old block sublist. |
| Old Blocks Time (Total) | Specifies how long in milliseconds a block inserted into the old sublist of the InnoDB buffer pool must stay there after its first access before it can be moved to the new sublist. |
| Online Alter Log Max Size (Total) | Specifies an upper limit on the size of the temporary log files used during online DDL operations for InnoDB tables. |
| Open Files (Total) | The maximum number of .ibd files that InnoDB can keep open at one time. |
| Page Cleaners (Total) | The number of page cleaner threads that flush dirty pages from buffer pool instances. |
| Page Size (Total) | Specifies the page size for all InnoDB tablespaces in a MySQL instance. This value is set when the instance is created and remains constant afterwards. You can specify page size using the values 16k (the default), 8k, or 4k. |
| Print All Deadlocks Enabled (Total) | When this option is enabled, information about all deadlocks in InnoDB user transactions is recorded in the mysqld error log. |
| Purge Batch Size (Total) | The granularity of changes, expressed in units of InnoDB redo log records, that trigger a purge operation, flushing the changed buffer pool blocks to disk. |
| Purge Rseg Truncate Frequency (Total) | Defines the frequency with which the purge system frees rollback segments. |
| Purge Threads (Total) | The number of background threads devoted to the InnoDB purge operation. |
| Random Read Ahead Enabled (Total) | Enables the random read-ahead technique for optimizing InnoDB I/O. |
| Read Ahead Threshold (Total) | The sensitivity of linear read-ahead that InnoDB uses to prefetch pages into the buffer cache. |
| Read Io Threads (Total) | The number of I/O threads for read operations in InnoDB. |
| Read Only Enabled (Total) | Starts the server in read-only mode. For distributing database applications or data sets on read-only media. Can also be used in data warehouses to share the same data directory between multiple instances. |
| Replication Delay (Total) | The replication thread delay (in ms) on a slave server if innodb_thread_concurrency is reached. |
| Rollback On Timeout Enabled (Total) | Whether InnoDB should rollback the entire transaction if a lock wait timeout is occurs, or just the last statement. |
| Sort Buffer Size (Total) | Specifies the sizes of several buffers used for sorting data during creation of an InnoDB index. |
| Spin Wait Delay (Total) | The maximum delay between polls for a spin lock. |
| Stats Auto Recalc Enabled (Total) | Causes InnoDB to automatically recalculate persistent statistics after the data in a table is changed substantially. The threshold value is currently 10% of the rows in the table. |
| Stats Method (Total) | How the server treats NULL values when collecting statistics about the distribution of index values for InnoDB tables. |
| Stats On Metadata Enabled (Total) | Whether InnoDB should update statistics during metadata statements such as SHOW TABLE STATUS, or when accessing the INFORMATION_SCHEMA tables TABLES or STATISTICS. |
| Stats Persistent (Total) | Specifies whether the InnoDB index statistics produced by the ANALYZE TABLE command are stored on disk, remaining consistent until a subsequent ANALYZE TABLE. Otherwise, the statistics are recalculated more frequently, such as at each server restart, which can lead to variations in query execution plans. |
| Stats Persistent Sample Pages (Total) | The number of index pages to sample when estimating cardinality and other statistics for an indexed column, such as those calculated by ANALYZE TABLE, for tables with persistent statistics. |
| Stats Sample Transient Pages (Total) | The number of InnoDB index pages to sample for index distribution statistics such as are calculated by ANALYZE TABLE. |
| Status File (Total) | Whether InnoDB should report the output of SHOW ENGINE INNODB Status to an innodb_status.<pid> file in the datadir. |
| Strict Mode Enabled (Total) | Whether InnoDB returns errors rather than warnings for exceptional conditions. |
| Support XA Enabled (Total) | Enables InnoDB support for two-phase commit in XA transactions. |
| Sync Array Size (Total) | Splits an internal data structure used to coordinate threads, for higher concurrency in workloads with large numbers of waiting threads. |
| Sync Spin Loops (Total) | The number of times a thread waits for an InnoDB mutex to be freed before the thread is suspended. |
| Table Locks Enabled (Total) | Whether InnoDB should honor LOCK TABLES if autocommit = 0. |
| Temp Data File Path (Total) | Specifies the path, file name, and file size for InnoDB temporary table tablespace data files. |
| Thread Concurrency (Total) | The maximum number of operating system threads concurrently allowed inside InnoDB for transactions. |
| Thread Sleep Delay (Total) | How long InnoDB threads sleep before joining the InnoDB queue, in microseconds. |
| Timed Mutexes Enabled (Total) | Whether mutex waits within InnoDB are timed or not. |
| Undo Directory (Total) | The relative or absolute directory path where InnoDB creates separate tablespaces for the undo logs. |
| Undo Logs (Total) | Defines how many rollback segments in the system tablespace that InnoDB uses within a transaction. |
| Undo Log Truncate Enabled (Total) | When you enable innodb_undo_log_truncate, undo tablespaces that exceed the threshold value defined by innodb_max_undo_log_size are marked for truncation. |
| Undo Tablespaces (Total) | The number of tablespace files that the undo logs are divided between, when you use a non-zero innodb_undo_logs setting. |
| Unique Checks Enabled (Total) | Whether uniqueness checks for secondary indexes are performed within InnoDB. |
| Use Native Aio Enabled (Total) | Whether to use the (Linux only) OS asynchronous IO subsystem. |
| Use Sys Malloc Enabled (Total) | Whether InnoDB uses the operating system memory allocator or its own. |
| Write Io Threads (Total) | The number of I/O threads for write operations in InnoDB. |
Lists the InnoDB Fulltext configuration metrics and provides a brief description of each.
Table 5.12 InnoDB Fulltext Configuration Metrics
| Name | Description |
|---|---|
| Aux Table (Total) | Specifies the qualified name of an InnoDB table containing a FULLTEXT index. |
| Cache Size (Total) | Size of the cache that holds a parsed document in memory while creating an InnoDB FULLTEXT index. |
| Enable Stopword (Total) | Specifies that a set of stopwords is associated with an InnoDB FULLTEXT index at the time the index is created. |
| Max Token Size (Total) | Maximum length of words that are stored in an InnoDB FULLTEXT index. |
| Min Token Size (Total) | Minimum length of words that are stored in an InnoDB FULLTEXT index. |
| Num Word Optimize (Total) | Number of words to process during each OPTIMIZE TABLE operation on an InnoDB FULLTEXT index. |
| Optimize Fulltext Only Enabled (Total) | Changes the way the OPTIMIZE TABLE statement operates on InnoDB tables. Intended to be enabled temporarily, during maintenance operations for InnoDB tables with FULLTEXT indexes. |
| Server Stopword Table (Total) | Name of the table containing a list of words to ignore when creating an InnoDB FULLTEXT index, in the format db_name/table_name. |
| Sort Pll Degree (Total) | Number of threads used in parallel to index and tokenize text in an InnoDB FULLTEXT index, when building a search index for a large table. |
| User Stopword Table (Total) | Name of the table containing a list of words to ignore when creating an InnoDB FULLTEXT index, in the format db_name/table_name. |
Lists the InnoDB Memcached Configuration configuration metrics and provides a brief description of each.
Table 5.13 InnoDB Memcached Configuration Configuration Metrics
| Name | Description |
|---|---|
| Bk Commit Interval (Total) | Specifies how often to auto-commit idle connections that use the InnoDB memcached interface. |
| Disable Rowlock Enabled (Total) | Disables row locks for op via the InnoDB memcached interface. |
| Enable Binlog Enabled (Total) | Enables binary logging of changes made via the InnoDB Memcached API. |
| Enable Mdl Enabled (Total) | Locks the table used by the InnoDB memcached plug-in, so that it cannot be dropped or altered by DDL through the SQL interface. |
| Engine Lib Name (Total) | Specifies the shared library that implements the InnoDB memcached plug-in. |
| Engine Lib Path (Total) | The path of the directory containing the shared library that implements the InnoDB memcached plug-in. |
| Options (Total) | Space-separated options that are passed to the underlying memcached daemon on startup. |
| Read Batch Size (Total) | Specifies how many memcached read operations (get) to perform before doing a COMMIT to start a new transaction. |
| Trx Level (Total) | Lets you control the transaction isolation level on queries processed by the memcached interface. 0 = READ UNCOMMITTED, 1 = READ COMMITTED, 2 = REPEATABLE READ 3 = SERIALIZABLE. |
| Write Batch Size (Total) | Specifies how many memcached write operations, such as add, set, or incr, to perform before doing a COMMIT to start a new transaction. |
Lists the Insert Delayed configuration metrics and provides a brief description of each.
Table 5.14 Insert Delayed Configuration Metrics
| Name | Description |
|---|---|
| Insert Limit (Total) | After inserting delayed_insert_limit delayed rows, the INSERT DELAYED handler thread checks whether there are any SELECT statements pending. |
| Insert Timeout (Total) | How many seconds an INSERT DELAYED handler thread should wait for INSERT statements before terminating. |
| Max Delayed Threads (Total) | Do not start more than this number of threads to handle INSERT DELAYED statements. |
| Queue Size (Total) | This is a per-table limit on the number of rows to queue when handling INSERT DELAYED statements. |
Lists the Localization configuration metrics and provides a brief description of each.
Table 5.15 Localization Configuration Metrics
| Name | Description |
|---|---|
| Date Format (Total) | This variable is unused. |
| Datetime Format (Total) | This variable is unused. |
| Default Week Format (Total) | The default mode value to use for the WEEK() function. |
| Language (Total) | The directory where error messages are located. |
| Messages (Total) | The locale to use for error messages. |
| Messages Dir (Total) | The directory where error messages are located. |
| System Time Zone (Total) | The server system time zone. |
| Time Format (Total) | The format to use for times, this variable is currently unused. |
| Time Names (Total) | This variable specifies the locale that controls the language used to display day and month names and abbreviations. |
| Time Zone (Total) | The timezone set for the instance. |
Lists the Logging configuration metrics and provides a brief description of each.
Table 5.16 Logging Configuration Metrics
| Name | Description |
|---|---|
| General Log Enabled (Total) | This option enables logging to the general query log, which contains entries that record client connections and SQL statements received from clients. |
| General Log File (Total) | The name of the general query log file. |
| Log Backward Compatible User Definitions Enabled (Total) | Whether to log the user_specification part of CREATE USER, ALTER USER, and GRANT statements in backward-compatible (pre-5.7.6) fashion |
| Log Error (Total) | Log errors and startup messages to this file. |
| Log Error Verbosity (Total) | This variable controls verbosity of the server in writing error, warning, and note messages to the error log. |
| Log Output (Total) | This option determines the destination for general query log and slow query log output. |
| Log Timestamps (Total) | This variable controls the timestamp time zone of error log messages, and of general query log and slow query log messages written to files. |
| Log Warnings (Total) | Print out warnings such as Aborted connection... to the error log. |
| SQL Log Disabled (Total) | If set to true, no logging is done to the general query log for this client. |
| Syslog Enabled (Total) | Whether to write error log output to syslog (on Unix and Unix-like systems) or Event Log (on Windows). |
| Syslog Facility (Total) | The facility for error log output written to syslog (what type of program is sending the message). This variable has no effect unless the log_syslog system variable is enabled. |
| Syslog Include Pid Enabled (Total) | Whether to include the server process ID in each line of error log output written to syslog. This variable has no effect unless the log_syslog system variable is enabled. |
| Syslog Tag (Total) | The tag to be added to the server identifier in error log output written to syslog. This variable has no effect unless the log_syslog system variable is enabled. |
Lists the Metadata configuration metrics and provides a brief description of each.
Table 5.17 Metadata Configuration Metrics
| Name | Description |
|---|---|
| License (Total) | The type of license the MySQL server has |
| Protocol Version (Total) | The version of the client/server protocol used by the MySQL server |
| Version (Total) | The version number for the MySQL server |
| Version Comment (Total) | The description of the MySQL server version built |
| Version Compile Machine (Total) | The type of machine or architecture on which MySQL was built |
| Version Compile Os (Total) | The type of operating system on which MySQL was built |
Lists the MyISAM configuration metrics and provides a brief description of each.
Table 5.18 MyISAM Configuration Metrics
| Name | Description |
|---|---|
| Concurrent Insert (Total) | Permits INSERT and SELECT statements to run concurrently for MyISAM tables that have no free blocks in the middle of the data file. |
| Delay Key Write (Total) | Delayed key writing causes key buffers not to be flushed between writes for MyISAM tables. |
| Keep Files On Create Enabled (Total) | Whether to overwrite MyISAM MYD/MYI files or return an error if no DATA DIRECTORY / INDEX DIRECTORY option is set, and the files already exist. |
| Key Buffer Size (Total) | The size of the buffer used for MyISAM index blocks. |
| Key Cache Age Threshold (Total) | Controls the demotion of buffers from the hot sublist of a MyISAM key cache to the warm sublist. |
| Key Cache Block Size (Total) | The size in bytes of blocks in the MyISAM key cache. |
| Key Cache Division Limit (Total) | The division point between the hot and warm sublists of the MyISAM key cache buffer list. |
| MyISAM Data Pointer Size (Total) | The default pointer size, in bytes, to be used by CREATE TABLE for MyISAM tables when no MAX_ROWS option is specified. |
| MyISAM Max Sort File Size (Total) | The maximum size of the temporary file that MySQL is permitted to use while re-creating a MyISAM index (during REPAIR TABLE, ALTER TABLE, or LOAD DATA INFILE). |
| MyISAM Mmap Size (Total) | The maximum amount of memory to use for memory mapping compressed MyISAM files. |
| MyISAM Recover Options (Total) | Sets the MyISAM storage engine recovery mode. |
| MyISAM Repair Threads (Total) | If this value is greater than 1, MyISAM table indexes are created in parallel (each index in its own thread) during the Repair by sorting process. |
| MyISAM Sort Buffer Size (Total) | The size of the buffer that is allocated when sorting MyISAM indexes during a REPAIR TABLE or when creating indexes with CREATE INDEX or ALTER TABLE. |
| MyISAM Stats Method (Total) | How the server treats NULL values when collecting statistics about the distribution of index values for MyISAM tables. |
| MyISAM Use Mmap Enabled (Total) | Use memory mapping for reading and writing MyISAM tables. |
| Skip External Locking Enabled (Total) | Do not use external locking (system locking) to lock MyISAMtable files. |
Lists the MyISAM Full Text configuration metrics and provides a brief description of each.
Table 5.19 MyISAM Full Text Configuration Metrics
| Name | Description |
|---|---|
| Boolean Syntax (Total) | The list of operators supported by boolean full-text searches performed using IN BOOLEAN MODE. |
| Max Word Len (Total) | The maximum length of the word to be included in a FULLTEXT index. |
| Min Word Len (Total) | The minimum length of the word to be included in a FULLTEXT index. |
| Query Expansion Limit (Total) | The number of top matches to use for full-text searches performed using WITH QUERY EXPANSION. |
| Stopword File (Total) | The file from which to read the list of stopwords for full-text searches. The server looks for the file in the data directory unless an absolute path name is given to specify a different directory. All the words from the file are used; comments are not honored. By default, a built-in list of stopwords is used (as defined in the storage/myisam/ft_static.c file). Setting this variable to the empty string ('') disables stopword filtering. |
Lists the NDB configuration metrics and provides a brief description of each.
Table 5.20 NDB Configuration Metrics
| Name | Description |
|---|---|
| Engine Condition Pushdown Enabled (Total) | The engine condition pushdown optimization enables processing for certain comparisons to be 'pushed down' to the storage engine level for more efficient execution. |
| NDB Autoincrement Prefetch Size (Total) | Determines the probability of gaps in an autoincremented column. |
Lists the Networking configuration metrics and provides a brief description of each.
Table 5.21 Networking Configuration Metrics
| Name | Description |
|---|---|
| Bind Address (Total) | The network interface(s) that MySQL is bound to. |
| Named Pipe Enabled (Total) | On Windows only, indicates whether the server supports connections over named pipes. |
| Port (Total) | The number of the port on which the server listens for TCP/IP connections. |
| Shared Memory Base Name (Total) | On Windows only, the name of shared memory to use for shared-memory connections. |
| Shared Memory Enabled (Total) | On Windows only, indicates whether the server the server permits shared-memory connections. |
| Skip Name Resolve Enabled (Total) | Whether to not resolve host names when checking client connections, and use only IP addresses instead. |
| Skip Networking Enabled (Total) | Whether to not listen for TCP/IP connections at all. |
| Socket (Total) | On Unix platforms, this variable is the name of the socket file that is used for local client connections. |
Lists the Optimizer configuration metrics and provides a brief description of each.
Table 5.22 Optimizer Configuration Metrics
| Name | Description |
|---|---|
| End Markers In JSON Enabled (Total) | Whether optimizer JSON output should add end markers. |
| Eq Range Index Dive Limit (Total) | Indicates the number of equality ranges in an equality comparison condition when the optimizer should switch from using index dives to index statistics in estimating the number of qualifying rows. |
| Max Length For Sort Data (Total) | The maximum size of parameter values that can be sent with the mysql_stmt_send_long_data() C API function. |
| Max Seeks For Key (Total) | Limit the assumed maximum number of seeks when looking up rows based on a key. |
| Max Sort Length (Total) | The number of bytes to use when sorting data values. Only the first max_sort_length bytes of each value are used; the rest are ignored. |
| Prune Level Enabled (Total) | Controls the heuristics applied during query optimization to prune less-promising partial plans from the optimizer search space. |
| Range Alloc Block Size (Total) | The size of blocks (in bytes) that are allocated when doing range optimization. |
| Search Depth (Total) | The maximum depth of search performed by the query optimizer. |
| Switch Value (Total) | The optimizer_switch system variable enables control over optimizer behavior. |
| Trace (Total) | Controls how to enable optimizer tracing. |
| Trace Features (Total) | Enables or disables selected optimizer tracing features. |
| Trace Limit (Total) | The maximum cumulative size of stored optimizer traces. |
| Trace Max MEM Size (Total) | The maximum cumulative size of stored optimizer traces. |
| Trace Offset (Total) | The offset of optimizer traces to display. |
Lists the Password Validation configuration metrics and provides a brief description of each.
Table 5.23 Password Validation Configuration Metrics
| Name | Description |
|---|---|
| Dictionary File (Total) | The path name of the dictionary file used by the validate_password plug-in for checking passwords. |
| Length (Total) | The minimum number of characters that passwords checked by the validate_password plug-in must have. |
| Mixed Case Count (Total) | The minimum number of lowercase and uppercase characters that passwords checked by the validate_password plug-in must have if the password policy is MEDIUM or stronger. |
| Number Count (Total) | The minimum number of numeric (digit) characters that passwords checked by the validate_password plug-in must have if the password policy is MEDIUM or stronger. |
| Policy (Total) | The password policy enforced by the validate_password plug-in. |
| Special Char Count (Total) | The minimum number of numeric (digit) characters that passwords checked by the validate_password plug-in must have if the password policy is MEDIUM or stronger. |
Lists the Performance Schema configuration metrics and provides a brief description of each.
Table 5.24 Performance Schema Configuration Metrics
| Name | Description |
|---|---|
| Accounts Size (Total) | The number of rows in the accounts table. |
| Digests Size (Total) | The maximum number of rows in the events_statements_summary_by_digest table. |
| Enabled (Total) | The value of this variable is ON or OFF to indicate whether the Performance Schema is enabled. By default, the value is OFF. At server startup, you can specify this variable with no value or a value of 1 to enable it, or with a value of 0 to disable it. |
| Events Stages History Long Size (Total) | The number of rows in the events_stages_history_long table. |
| Events Stages History Size (Total) | The number of rows in the events_stages_history table. |
| Events Statements History Long Size (Total) | The number of rows in the events_statements_history_long table. |
| Events Statements History Size (Total) | The number of rows in the events_statements_history table. |
| Events Transactions History Long Size (Total) | The number of rows in the events_transactions_history_long table. |
| Events Transactions History Size (Total) | The number of rows per thread in the events_transactions_history table. |
| Events Waits History Long Size (Total) | The number of rows in the events_waits_history_long table. |
| Events Waits History Size (Total) | The number of rows per thread in the events_waits_history table. |
| Hosts Size (Total) | The number of rows in the hosts table. |
| Max Cond Classes (Total) | The maximum number of condition instruments. |
| Max Cond Instances (Total) | The maximum number of instrumented condition objects. |
| Max Digest Length (Total) | The maximum number of bytes available for computing statement digests. |
| Max File Classes (Total) | The maximum number of file instruments. |
| Max File Handles (Total) | The maximum number of opened file objects. The value of performance_schema_max_file_handles should be greater than the value of open_files_limit: open_files_limit affects the maximum number of open file handles the server can support and performance_schema_max_file_handles affects how many of these file handles can be instrumented. |
| Max File Instances (Total) | The maximum number of instrumented file objects. |
| Max Index Stat (Total) | The maximum number of indexes for which the Performance Schema maintains statistics. |
| Max Memory Classes (Total) | The maximum number of memory instruments. |
| Max Metadata Locks (Total) | The maximum number of metadata lock instruments. |
| Max Mutex Classes (Total) | The maximum number of mutex instruments. |
| Max Mutex Instances (Total) | The maximum number of instrumented mutex objects. |
| Max Prepared Statements Instances (Total) | The maximum number of rows in the prepared_statements_instances table. |
| Max Program Instances (Total) | The maximum number of stored programs for which the Performance Schema maintains statistics. |
| Max Rwlock Classes (Total) | The maximum number of rwlock instruments. |
| Max Rwlock Instances (Total) | The maximum number of instrumented rwlock objects. |
| Max Socket Classes (Total) | The maximum number of socket instruments. |
| Max Socket Instances (Total) | The maximum number of instrumented socket objects. |
| Max SQL Text Length (Total) | The maximum number of bytes used to store SQL statements in the SQL_TEXT column of the events_statements_current, events_statements_history, and events_statements_history_long statement event tables. |
| Max Stage Classes (Total) | The maximum number of stage instruments. |
| Max Statement Classes (Total) | The maximum number of statement instruments. The default value is calculated at server build time based on the number of commands in the client/server protocol and the number of SQL statement types supported by the server. |
| Max Statement Stack (Total) | The maximum depth of nested stored program calls for which the Performance Schema maintains statistics. |
| Max Table Handles (Total) | The maximum number of opened table objects. |
| Max Table Instances (Total) | The maximum number of instrumented table objects. |
| Max Table Lock Stat (Total) | The maximum number of tables for which the Performance Schema maintains lock statistics. |
| Max Thread Classes (Total) | The maximum number of thread instruments. |
| Max Thread Instances (Total) | The maximum number of instrumented thread objects. The max_connections and max_delayed_threads system variables affect how many threads are run in the server. performance_schema_max_thread_instances affects how many of these running threads can be instrumented. If you increase max_connections or max_delayed_threads, you should consider increasing performance_schema_max_thread_instances so that performance_schema_max_thread_instances is greater than the sum of max_connections and max_delayed_threads. |
| Session Connect Attrs Size (Total) | The amount of preallocated memory per thread used to hold connection attribute strings. |
| Setup Actors Size (Total) | The number of rows in the setup_actors table. |
| Setup Objects Size (Total) | The number of rows in the setup_objects table. |
| Users Size (Total) | The number of rows in the users table. |
Lists the Query Cache configuration metrics and provides a brief description of each.
Table 5.25 Query Cache Configuration Metrics
| Name | Description |
|---|---|
| Limit (Total) | The maximum size (in bytes) of result sets to cache within the Query Cache. Result sets larger than this size will not be cached. |
| Min Res Unit (Total) | The minimum size (in bytes) for blocks allocated by the query cache. |
| Query Cache Enabled (Total) | Whether the MySQL server supports the Query Cache or not. |
| Size (Total) | The total amount of memory (in bytes) to allocate for caching query results within the Query Cache. |
| Type (Total) | Controls how the query cache decides whether to cache Select statements, based on the SQL_NO_CACHE and SQL_CACHE keywords. |
| Wlock Invalidate Enabled (Total) | Causes acquisition of a WRITE lock for a table to invalidate any queries in the Query Cache that refer to the table. |
Lists the Replication Master configuration metrics and provides a brief description of each.
Table 5.26 Replication Master Configuration Metrics
| Name | Description |
|---|---|
| Auto Increment Increment (Total) | Controls the interval between successive column values within all AUTO_INCREMENT columns within the MySQL server. |
| Auto Increment Offset (Total) | Determines the starting point for the AUTO_INCREMENT column values within the MySQL server. |
| Enforce Gtid Consistency Enabled (Total) | Allows execution of only those statements that can be logged in a transactionally safe manner. |
| Gtid Executed (Total) | Contains a representation of the set of all transactions that are logged in the binary log. |
| Gtid Executed Compression Period (Total) | Compress the mysql.gtid_executed table each time this many transactions have been processed. A setting of 0 means that this table is not compressed. Since no compression of the table occurs when using the binary log, setting the value of the variable has no effect unless binary logging is disabled. |
| Gtid Mode (Total) | Shows whether GTIDs are enabled. |
| Gtid Next (Total) | Specifies whether and how the next GTID is obtained. |
| Gtid Owned (Total) | Holds a list of all GTIDs along with their owners. |
| Gtid Purged (Total) | The set of all transactions that have been purged from the binary log. |
| Info Repository (Total) | The setting of this variable determines whether the slave logs master status and connection information to a FILE (master.info), or to a TABLE (mysql.slave_master_info). |
| Recovery Rank (Total) | null |
| Repl UUID (Total) | The MySQL server's UUID, this variable is only available on versions > 5.6.1. |
| Semi Sync Master Enabled (Total) | Whether semisynchronous replication is enabled on the master MySQL server. |
| Semi Sync Master Timeout (Total) | How long the master waits on a commit (in milliseconds) for acknowledgment from a slave before timing out and reverting to asynchronous replication. |
| Semi Sync Master Trace Level (Total) | The semisynchronous replication debug trace level on the master. |
| Semi Sync Master Wait No Slave Enabled (Total) | Whether the master waits for the timeout to expire before reverting to normal replication even if the slave count drops to zero during the timeout period. |
| Server Id (Total) | The server ID, used in replication to give each master and slave a unique identity. |
| Verify Checksum Enabled (Total) | Enabling this option causes the master to verify events from the binary log using checksums, and to stop with an error in the event of a mismatch. |
Lists the Replication Slave configuration metrics and provides a brief description of each.
Table 5.27 Replication Slave Configuration Metrics
| Name | Description |
|---|---|
| Allow Batching Enabled (Total) | Whether or not batched updates are enabled on replication slaves. |
| Auto Position Enabled (Total) | The set of global transaction IDs for all received transactions subsequently executed on this slave. Empty if GTIDs are not in use. |
| Checkpoint Group (Total) | Sets the maximum number of transactions that can be processed by a multi-threaded slave before a checkpoint operation is called to update its status as shown by SHOW SLAVE STATUS. Setting this option has no effect on slaves for which multithreading is not enabled. |
| Checkpoint Period (Total) | Sets the maximum time (in milliseconds) that is allowed to pass before a checkpoint operation is called to update the status of a multi-threaded slave as shown by SHOW SLAVE STATUS. Setting this variable has no effect on slaves for which multithreading is not enabled. |
| Compressed Protocol Enabled (Total) | Whether to use compression for the slave/master protocol if both the slave and the master support it. |
| Connect Retry (Total) | The number of seconds between connect retries to the master. |
| Exec Mode (Total) | Controls whether IDEMPOTENT or STRICT mode is used in replication conflict resolution and error checking. |
| Gtid Mode (Total) | Shows whether GTIDs are enabled. |
| Init Slave (Total) | A string to be executed by a slave server each time the SQL thread starts. The format of the string is the same as for the init_connect variable. |
| Load Tmpdir (Total) | The name of the directory where the slave creates temporary files for replicating LOAD DATA INFILE statements. |
| Log Slave Updates Enabled (Total) | Whether the slave should log the updates performed by its SQL thread to its own binary log. |
| Master Bind Address (Total) | When a replication slave has multiple network interfaces, determines which of the slave's network interfaces is chosen for connecting to the master. |
| Master Host (Total) | The master host that the slave is connected to. |
| Master Inet Address (Total) | The internet address as determined by the collecting agent, so as to mimic the DNS lookup as close as possible to what the mysql server would have done. |
| Master Info File (Total) | The name and location of the master.info file. |
| Master Port (Total) | The port used to connect to the master. |
| Master Retry Count (Total) | The number of times that the slave tries to connect to the master before giving up. Reconnects are attempted at intervals set by the MASTER_CONNECT_RETRY option of the CHANGE MASTER TO statement (default 60). |
| Master Server Id (Total) | The server_id variable value from the master. |
| Master Server Inv Uuid (Total) | The uuid from the master mysql.inventory table, generated by MySQL Enterprise Monitor. |
| Master Server Repl Uuid (Total) | The master servers server_uuid variable. |
| Master SSL Allowed Enabled (Total) | Whether slave's the master server allows SSL connections. |
| Master SSL Ca File (Total) | The path to a file that contains a list of trusted SSL CAs for use when connecting to the slave's master. |
| Master SSL Ca Path (Total) | The path to a directory that contains trusted SSL CA certificates in PEM format for use when connecting to the slave's master. |
| Master SSL Cert (Total) | The name of the SSL certificate file to use for establishing a secure connection to the slave's master. |
| Master SSL Cipher (Total) | A list of permissible ciphers to use for SSL encryption when connecting to the slave's master. |
| Master SSL Crl (Total) | The name of the file containing a Certificate Revocation List. |
| Master SSL Crl Path (Total) | The path to a directory that contains Certificate Revocation List files. |
| Master SSL Key (Total) | The name of the SSL key file to use for establishing a secure connection to the slave's master. |
| Master SSL Verify Server Cert Enabled (Total) | Whether the slave should verify the Common Name value in the certificate that the master sends to it against the host name that the slave uses for connecting to the master. The connection is rejected if there is a mismatch. |
| Master User (Total) | The user name of the account used to connect to the master. |
| Max Allowed Packet (Total) | Sets the maximum packet size for the slave SQL and I/O threads, so that large updates using row-based replication do not cause replication to fail because an update exceeded max_allowed_packet. |
| Max Relay Log Size (Total) | The size at which the server rotates relay log files automatically. |
| Net Timeout (Total) | The number of seconds to wait for more data from a master/slave connection before aborting the read. |
| Parallel Type (Total) | Normally, transactions are applied in parallel only if they do not make any changes in the same database. Beginning with MySQL 5.7.2, it is possible to enable parallel execution on the slave of all uncommitted threads already in the prepare phase, without violating consistency, using this variable. |
| Parallel Workers (Total) | Sets the number of slave worker threads for executing replication events (transactions) in parallel. Setting this variable to 0 (the default) disables parallel execution. |
| Pending Jobs Size Max (Total) | For multi threaded slaves, this variable sets the maximum amount of memory (in bytes) available to slave worker queues holding events not yet applied. |
| Preserve Commit Order (Total) | For multi-threaded slaves, enabling this variable ensures that transactions are externalized on the slave in the same order as they appear in the slave's relay log. Setting this variable has no effect on slaves for which multi-threading is not enabled. |
| Read Only Enabled (Total) | When this property is enabled, the server permits no updates except from users that have the SUPER privilege. |
| Relay Log (Total) | The name of the relay log file. |
| Relay Log Basename (Total) | Holds the name and complete path to the relay log file. |
| Relay Log Index (Total) | The name to use for the slave relay log index file. |
| Relay Log Info File (Total) | The name to use for the file in which the slave records information about the relay logs. |
| Relay Log Info Repository (Total) | Determines whether the slave's position in the relay logs is written to a FILE (relay-log.info) or to a TABLE (mysql.slave_relay_log_info). |
| Relay Log Purge Enabled (Total) | Disables or enables automatic purging of relay log files as soon as they are not needed any more. |
| Relay Log Recovery Enabled (Total) | Enables automatic relay log recovery immediately following server startup, which means that the replication slave discards all unprocessed relay logs and retrieves them from the replication master. |
| Relay Log Space Limit (Total) | The maximum amount of space to use for all relay logs. |
| Replicate Do DB (Total) | Whether the slave SQL thread should restrict replication to statements where the default database (the one selected by USE) is one of those listed. |
| Replicate Do Table (Total) | Whether the slave SQL thread should restrict replication to the specified table(s). |
| Replicate Ignore DB (Total) | Whether the slave SQL thread should not replicate any statement where the default database (the one selected by USE) is one of those listed. |
| Replicate Ignore Server Ids (Total) | Whether the slave should ignore events from 0 or more masters using the IGNORE_SERVER_IDS option in a CHANGE MASTER TO statement. |
| Replicate Ignore Table (Total) | Whether the slave SQL thread should not replicate any statement that updates the specified table(s), even if any other tables might be updated by the same statement. |
| Replicate Wild Do Table (Total) | Whether the slave thread should restrict replication to statements where any of the updated tables match the specified database and table name patterns. |
| Replicate Wild Ignore Table (Total) | Whether the slave thread should not replicate a statement where any table matches the given wildcard pattern. |
| Report Host (Total) | The host name or IP address of the slave to be reported to the master during slave registration. |
| Report Password (Total) | The account password of the slave to be reported to the master during slave registration. |
| Report Port (Total) | The TCP/IP port number for connecting to the slave, to be reported to the master during slave registration. |
| Report User (Total) | The account user name of the slave to be reported to the master during slave registration. |
| Rows Search Algorithms (Total) | When preparing batches of rows for row-based logging and replication using slave_allow_batching, this option controls how the rows are searched for matches - that is, whether or not hashing is used for searches using a primary or unique key, some other key, or no key at all. |
| Semi Sync Slave Enabled (Total) | Whether semisynchronous replication is enabled on the slave. |
| Semi Sync Slave Trace Level (Total) | The semisynchronous replication debug trace level on the slave. |
| Server Id (Total) | The server ID, used in replication to give each master and slave a unique identity. |
| Skip Counter (Total) | The number of events from the master that a slave server should skip. |
| Skip Errors (Total) | Tells the slave SQL thread to continue replication when a statement returns any of the errors listed in the variable value. |
| SQL Delay (Total) | The length of time the slave SQL thread should delay applying events from the relay logs when using time delayed replication. |
| SQL Verify Checksum Enabled (Total) | When preparing batches of rows for row-based logging and replication using slave_allow_batching, this option controls how the rows are searched for matches - that is, whether or not hashing is used for searches using a primary or unique key, some other key, or no key at all. |
| Sync Master Info (Total) | If the value of this variable is greater than 0, a replication slave synchronizes its master.info file to disk (using fdatasync()) after every sync_master_info events. |
| Sync Relay Log (Total) | If the value of this variable is greater than 0, the MySQL server synchronizes its relay log to disk (using fdatasync()) after every sync_relay_log writes to the relay log. |
| Sync Relay Log Info (Total) | If the value of this variable is greater than 0, a replication slave synchronizes its relay-log.info file to disk (using fdatasync()) after every sync_relay_log_info transactions. |
| Transaction Retries (Total) | How many times the slave SQL thread should retry a transaction because of an InnoDB deadlock or because the transaction's execution time exceeded InnoDB's innodb_lock_wait_timeout. |
| Type Conversions (Total) | Controls the type conversion mode in effect on the slave when using row-based replication. |
| Until Condition (Total) | Whether the slave was started with a START SLAVE UNTIL condition. |
| Until Log File (Total) | The master or relay log file that the slave will stop executing at, if started with a START SLAVE UNTIL condition. |
| Until Log Pos (Total) | The master or relay log position that the slave will stop executing at, if started with a START SLAVE UNTIL condition. |
Lists the Secure Connections configuration metrics and provides a brief description of each.
Table 5.28 Secure Connections Configuration Metrics
| Name | Description |
|---|---|
| Ca (Total) | The path to a file that contains a list of trusted SSL CAs. |
| Ca Path (Total) | The name of the SSL certificate file to use for establishing a secure connection. |
| Cert (Total) | The name of the SSL certificate file to use for establishing a secure connection. |
| Cipher (Total) | A list of permissible ciphers to use for SSL encryption. For greatest portability, cipher_list should be a list of one or more cipher names, separated by colons. |
| Crl (Total) | The path to a file containing certificate revocation lists in PEM format. Revocation lists work for MySQL distributions compiled against OpenSSL (but not yaSSL). |
| Crl Path (Total) | The path to a directory that contains files containing certificate revocation lists in PEM format. Revocation lists work for MySQL distributions compiled against OpenSSL (but not yaSSL). |
| Key (Total) | The name of the SSL key file to use for establishing a secure connection. |
Lists the Security configuration metrics and provides a brief description of each.
Table 5.29 Security Configuration Metrics
| Name | Description |
|---|---|
| Auto Generate Certs Enabled (Total) | This variable is available if the server was compiled using OpenSSL. It controls whether the server autogenerates SSL key and certificate files in the data directory, if they do not already exist. |
| Automatic Sp Privileges Enabled (Total) | When this variable has a value of 1 (the default), the server automatically grants the EXECUTE and ALTER ROUTINE privileges to the creator of a stored routine, if the user cannot already execute and alter or drop the routine. |
| Check Proxy Users Enabled (Total) | This variable controls whether the server performs proxy user mapping for authentication plugins that request it. With check_proxy_users enabled, it may also be necessary to enable plug-in-specific system variables to take advantage of server proxy user mapping support. |
| Default Authentication Plugin (Total) | The default authentication plug-in. Permitted values are mysql_native_password (use MySQL native passwords; this is the default) and sha256_password (use SHA-256 passwords). |
| Default Password Lifetime (Total) | This variable defines the global automatic password expiration policy. It applies to accounts that use MySQL built-in authentication methods (accounts that use an authentication plug-in of mysql_native_password, mysql_old_password, or sha256_password). If the value of default_password_lifetime is a positive integer N, it indicates the permitted password lifetime; passwords must be changed every N days. A value of 0 disables automatic password expiration. The default is 360; passwords must be changed approximately once per year. |
| Disconnect On Expired Password Enabled (Total) | Controls how the server handles clients with expired passwords. |
| Local Infile Enabled (Total) | Whether LOCAL is supported for LOAD DATA INFILE statements. |
| Mysql Native Password Proxy Users Enabled (Total) | This variable controls whether the mysql_native_password built-in authentication plug-in supports proxy users. It has no effect unless the check_proxy_users system variable is enabled. |
| Old Passwords Enabled (Total) | Whether the server should use pre-4.1-style passwords for MySQL user accounts. |
| Secure Auth Enabled (Total) | Disallow authentication by clients that attempt to use accounts that have old (pre-4.1) passwords. |
| Secure File Privileges (Total) | If set to the name of a directory, it limits the effect of the LOAD_FILE() function and the LOAD DATA and SELECT ... INTO OUTFILE statements to work only with files in that directory. |
| Sha256 Password Auto Generate RSA Keys Enabled (Total) | This variable is available if the server was compiled using OpenSSL. It controls whether the server autogenerates RSA private/public key-pair files in the data directory, if they do not already exist. |
| Sha256 Password Private Key Path (Total) | The path name of the RSA private key file for the sha256_password authentication plug-in. If the file is named as a relative path, it is interpreted relative to the server data directory. The file must be in PEM format. Because this file stores a private key, its access mode should be restricted so that only the MySQL server can read it. |
| Sha256 Password Proxy Users Enabled (Total) | This variable controls whether the sha256_password built-in authentication plug-in supports proxy users. It has no effect unless the check_proxy_users system variable is enabled. |
| Sha256 Password Public Key Path (Total) | The path name of the RSA public key file for the sha256_password authentication plug-in. If the file is named as a relative path, it is interpreted relative to the server data directory. The file must be in PEM format. Because this file stores a public key, copies can be freely distributed to client users. |
| Skip Show Database Enabled (Total) | With this option, the SHOW DATABASES statement is permitted only to users who have the SHOW DATABASES privilege, and the statement displays all database names. |
| Validate User Plugins Enabled (Total) | If this variable is enabled (the default), the server checks each user account and produces a warning if conditions are found that would make the account unusable. |
Lists the Slow Query Logging configuration metrics and provides a brief description of each.
Table 5.30 Slow Query Logging Configuration Metrics
| Name | Description |
|---|---|
| Log Queries Not Using Indexes Enabled (Total) | If you are using this option with the slow query log enabled, queries that are expected to retrieve all rows are logged. |
| Log Slow Admin Statements Enabled (Total) | Log slow administrative statements such as OPTIMIZE TABLE, ANALYZE TABLE, and ALTER TABLE to the slow query log. |
| Log Slow Queries Enabled (Total) | This option enables logging to the slow query log, which contains entries for all queries that have taken more than long_query_time seconds to execute. |
| Log Slow Slave Statements Enabled (Total) | When the slow query log is enabled, this option enables logging for queries that have taken more than long_query_time seconds to execute on the slave. |
| Log Throttle Queries Not Using Indexes Enabled (Total) | If log_queries_not_using_indexes is enabled, the log_throttle_queries_not_using_indexes variable limits the number of such queries per minute that can be written to the slow query log. |
| Long Query Time (Total) | If a query takes longer than this many seconds, the server increments the Slow_queries status variable. |
| Min Examined Row Limit (Total) | Queries that examine fewer than this number of rows are not logged to the slow query log. |
| Slow Query Log File (Total) | The name of the slow query log file |
Lists the Statement Processing configuration metrics and provides a brief description of each.
Table 5.31 Statement Processing Configuration Metrics
| Name | Description |
|---|---|
| Auto Is Null Enabled (Total) | If this variable is set to 1, then after a statement that successfully inserts an automatically generated AUTO_INCREMENT value, you can find that value by issuing a statement of the following form: SELECT * FROM tbl_name WHERE auto_col IS NULL If the statement returns a row, the value returned is the same as if you invoked the LAST_INSERT_ID() function. |
| Big Selects Enabled (Total) | If set to 0, MySQL aborts SELECT statements that are likely to take a very long time to execute (that is, statements for which the optimizer estimates that the number of examined rows exceeds the value of max_join_size). This is useful when an inadvisable WHERE statement has been issued. |
| Buffer Result Enabled (Total) | If set to 1, sql_buffer_result forces results from SELECT statements to be put into temporary tables. This helps MySQL free the table locks early and can be beneficial in cases where it takes a long time to send results to the client. |
| Div Precision Increment (Total) | Indicates the number of digits by which to increase the scale of the result of division operations performed with the / operator. |
| Group Concat Max Len (Total) | The maximum permitted result length in bytes for the GROUP_CONCAT() function. |
| Internal Tmp Disk Storage Engine (Total) | The storage engine for on-disk internal temporary tables. Permitted values are MYISAM and INNODB. |
| Max Digest Length (Total) | The maximum number of bytes available for computing statement digests. When this amount of space is used for computing the digest for a statement, no further tokens from the parsed statement are collected or figure into the digest value. Statements differing only after that many bytes of parsed statement tokens produce the same digest and are aggregated for digest statistics. |
| Max Error Count (Total) | The maximum number of error, warning, and note messages to be stored for display by the SHOW ERRORS and SHOW WARNINGS statements. |
| Max Execution Time (Total) | The execution timeout for SELECT statements, in milliseconds. If the value is 0, timeouts are not enabled. |
| Max Join Size (Total) | Do not permit statements that probably need to examine more than max_join_size rows (for single-table statements) or row combinations (for multiple-table statements) or that are likely to do more than max_join_size disk seeks. |
| Max Prepared Stmt Count (Total) | Limits the total number of prepared statements in the server. |
| Max Sp Recursion Depth (Total) | The number of times that any given stored procedure may be called recursively. Stored procedure recursion increases the demand on thread stack space. If you increase the value of max_sp_recursion_depth, it may be necessary to increase thread stack size by increasing the value of thread_stack at server startup. |
| Max Write Lock Count (Total) | After this many write locks, permit some pending read lock requests to be processed in between. |
| Notes Enabled (Total) | If set to 1 (the default), warnings of Note level increment warning_count and the server records them. If set to 0, Note warnings do not increment warning_count and the server does not record them. |
| Quote Show Create Enabled (Total) | If set to 1 (the default), the server quotes identifiers for SHOW CREATE TABLE and SHOW CREATE DATABASE statements. If set to 0, quoting is disabled. |
| Safe Updates Enabled (Total) | If set to 1, MySQL aborts UPDATE or DELETE statements that do not use a key in the WHERE clause or a LIMIT clause. This makes it possible to catch UPDATE or DELETE statements where keys are not used properly and that would probably change or delete a large number of rows. |
| Select Limit (Total) | The maximum number of rows to return from SELECT statements. The default value for a new connection is the maximum number of rows that the server permits per table. |
| Warnings Enabled (Total) | This variable controls whether single-row INSERT statements produce an information string if warnings occur. |
Lists the Table Configuration configuration metrics and provides a brief description of each.
Table 5.32 Table Configuration Configuration Metrics
| Name | Description |
|---|---|
| Big Tables Enabled (Total) | Enable large result sets by saving all temporary sets in files. |
| Default Storage Engine (Total) | Sets the default storage engine for tables. |
| Default Tmp Storage Engine (Total) | Sets the default storage engine for temporary tables (created with CREATE TEMPORARY TABLE). |
| Explicit Defaults For Timestamp Enabled (Total) | Sets whether TIMESTAMP columns should have an explicit DEFAULT clause. |
| Flush Enabled (Total) | Whether to flush (synchronize) all changes to disk after each SQL statement. |
| Flush Time (Total) | How often (in seconds) to close all tables, to free up resources and synchronize unflushed data to disk, for low resource systems. |
| Lock Wait Timeout (Total) | This timeout applies to all statements that use metadata locks. These include DML and DDL operations on tables, views, stored procedures, and stored functions, as well as LOCK TABLES, FLUSH TABLES WITH READ LOCK, and HANDLER statements. |
| Lower Case File System Enabled (Total) | describes the case sensitivity of file names on the file system where the data directory is located. OFF means file names are case sensitive, ON means they are not case sensitive. |
| Lower Case Table Names (Total) | Whether table names are stored in lowercase or uppercase on disk, and whether comparisons are case sensitive or not. |
| Low Priority Updates Enabled (Total) | When enabled, all INSERT, UPDATE, DELETE, and LOCK TABLE WRITE statements wait until there is no pending SELECT or LOCK TABLE READ on the affected table. This affects only storage engines that use only table-level locking (such as MyISAM, MEMORY, and MERGE). |
| Max Heap Table Size (Total) | The maximum size to which user-created MEMORY tables are permitted to grow. |
| Max Tmp Tables (Total) | The maximum number of temporary tables a client can keep open at the same time. (This variable does not yet do anything.). |
| Metadata Locks Cache Size (Total) | The size of the metadata locks cache. The server uses this cache to avoid creation and destruction of synchronization objects. |
| Metadata Locks Hash Instances (Total) | The set of metadata locks can be partitioned into separate hashes to permit connections accessing different objects to use different locking hashes and reduce contention. |
| Old Alter Table Enabled (Total) | Whether to revert to using a temporary table, copying over the data, and then renaming the temporary table to the original, as used by MySQL 5.0 and earlier. |
| Open Files Limit (Total) | Changes the number of file descriptors available to mysqld. |
| Sync Frm Enabled (Total) | If this variable is set to 1, when any nontemporary table is created its .frm file is synchronized to disk (using fdatasync()). |
| Table Definition Cache (Total) | The number of table definitions that can be stored in the definition cache. |
| Table Open Cache (Total) | The number of concurrently open tables for all threads allowed. |
| Table Open Cache Instances (Total) | The number of open tables cache instances (default 1). To improve scalability by reducing contention among sessions, the open tables cache can be partitioned into several smaller cache instances of size table_open_cache / table_open_cache_instances . |
| Tmp Table Size (Total) | The maximum size to which in-memory temporary tables are permitted to grow before being automatically converting to an on-disk temporary table. |
| Updatable Views With Limit Enabled (Total) | If this variable is set to 1, when any nontemporary table is created its .frm file is synchronized to disk (using fdatasync()). |
Lists the Thread Pool configuration metrics and provides a brief description of each.
Table 5.33 Thread Pool Configuration Metrics
| Name | Description |
|---|---|
| Algorithm (Total) | This variable controls which algorithm the thread pool plug-in uses. A value of 0 (the default) uses a conservative low-concurrency algorithm which is most well tested and is known to produce very good results. A value of 1 increases the concurrency and uses a more aggressive algorithm which at times has been known to perform 5-10% better on optimal thread counts, but has degrading performance as the number of connections increases. |
| High Priority Connection (Total) | This variable affects queuing of new statements prior to execution. If the value is 0 (false, the default), statement queuing uses both the low-priority and high-priority queues. If the value is 1 (true), queued statements always go to the high-priority queue. |
| Max Unused Threads (Total) | The maximum permitted number of unused threads in the thread pool. This variable makes it possible to limit the amount of memory used by sleeping threads. |
| Prio Kickup Timer (Total) | This variable affects statements waiting for execution in the low-priority queue. The value is the number of milliseconds before a waiting statement is moved to the high-priority queue. |
| Size (Total) | The number of thread groups in the thread pool. This is the most important parameter controlling thread pool performance. It affects how many statements can execute simultaneously. |
| Stall Limit (Total) | The value is the amount of time a statement has to finish after starting to execute before it becomes defined as stalled, at which point the thread pool permits the thread group to begin executing another statement. |
Lists the Threads configuration metrics and provides a brief description of each.
Table 5.34 Threads Configuration Metrics
| Name | Description |
|---|---|
| Cache Size (Total) | How many threads the server should cache for reuse. |
| Concurrency (Total) | This variable is specific to Solaris systems, for which mysqld invokes the thr_setconcurrency() with the variable value. |
| Handling (Total) | The thread-handling model used by the server for connection threads. The permissible values are no-threads (the server uses a single thread) and one-thread-per-connection. |
| Slow Launch Time (Total) | If creating a thread takes longer than this many seconds, the server increments the Slow_launch_threads status variable. |
| Stack Size (Total) | The stack size for each thread. |
Lists the Transactions configuration metrics and provides a brief description of each.
Table 5.35 Transactions Configuration Metrics
| Name | Description |
|---|---|
| Autocommit Enabled (Total) | The autocommit mode. If set to 1, all changes to a table take effect immediately. If set to 0, you must use COMMIT to accept a transaction or ROLLBACK to cancel it. |
| Completion Type (Total) | Affects transactions that begin with START TRANSACTION or BEGIN and end with COMMIT or ROLLBACK. Sets whether the server should start a new transaction immediately after a COMMIT/ROLLBACK (by setting to CHAIN), or disconnect after completing a COMMIT/ROLLBACK (by setting to RELEASE), otherwise do not implicitly start a new transaction (by setting to NO_CHAIN, the default). |
| Isolation (Total) | The default transaction isolation level. |
| Read Only Enabled (Total) | The default transaction access mode. The value can be OFF (read/write, the default) or ON (read only). |