MySQL :: MySQL 8.4 Reference Manual :: 7.1.10 Server Status Variables (original) (raw)

The MySQL server maintains many status variables that provide information about its operation. You can view these variables and their values by using the SHOW [GLOBAL | SESSION] STATUS statement (see Section 15.7.7.37, “SHOW STATUS Statement”). The optional GLOBAL keyword aggregates the values over all connections, and SESSION shows the values for the current connection.

The status variables have the following meanings.

• Aborted_clients
  The number of connections that were aborted because the client died without closing the connection properly. SeeSection B.3.2.9, “Communication Errors and Aborted Connections”.
• Aborted_connects
  The number of failed attempts to connect to the MySQL server. See Section B.3.2.9, “Communication Errors and Aborted Connections”.
  For additional connection-related information, check theConnection_errors_ xxx status variables and thehost_cache table.
• Authentication_ldap_sasl_supported_methods
  The authentication_ldap_sasl plugin that implements SASL LDAP authentication supports multiple authentication methods, but depending on host system configuration, they might not all be available. TheAuthentication_ldap_sasl_supported_methods variable provides discoverability for the supported methods. Its value is a string consisting of supported method names separated by spaces. Example: "SCRAM-SHA 1 SCRAM-SHA-256 GSSAPI"
• Binlog_cache_disk_use
  The number of transactions that used the temporary binary log cache but that exceeded the value ofbinlog_cache_size and used a temporary file to store statements from the transaction.
  The number of nontransactional statements that caused the binary log transaction cache to be written to disk is tracked separately in theBinlog_stmt_cache_disk_use status variable.
• Acl_cache_items_count
  The number of cached privilege objects. Each object is the privilege combination of a user and its active roles.
• Binlog_cache_use
  The number of transactions that used the binary log cache.
• Binlog_stmt_cache_disk_use
  The number of nontransaction statements that used the binary log statement cache but that exceeded the value ofbinlog_stmt_cache_size and used a temporary file to store those statements.
• Binlog_stmt_cache_use
  The number of nontransactional statements that used the binary log statement cache.
• Bytes_received
  The number of bytes received from all clients.
• Bytes_sent
  The number of bytes sent to all clients.
• Caching_sha2_password_rsa_public_key
  The public key used by thecaching_sha2_password authentication plugin for RSA key pair-based password exchange. The value is nonempty only if the server successfully initializes the private and public keys in the files named by thecaching_sha2_password_private_key_path andcaching_sha2_password_public_key_path system variables. The value ofCaching_sha2_password_rsa_public_key comes from the latter file.
• Com_ _`xxx`_
  The Com_ _`xxx`_ statement counter variables indicate the number of times each_xxx_ statement has been executed. There is one status variable for each type of statement. For example, Com_delete andCom_update countDELETE andUPDATE statements, respectively. Com_delete_multi andCom_update_multi are similar but apply toDELETE andUPDATE statements that use multiple-table syntax.
  All Com_stmt_ _`xxx`_ variables are increased even if a prepared statement argument is unknown or an error occurred during execution. In other words, their values correspond to the number of requests issued, not to the number of requests successfully completed. For example, because status variables are initialized for each server startup and do not persist across restarts, theCom_restart andCom_shutdown variables that trackRESTART andSHUTDOWN statements normally have a value of zero, but can be nonzero ifRESTART orSHUTDOWN statements were executed but failed.
  The Com_stmt_ _`xxx`_ status variables are as follows:
  • Com_stmt_prepare
  • Com_stmt_execute
  • Com_stmt_fetch
  • Com_stmt_send_long_data
  • Com_stmt_reset
  • Com_stmt_close
    Those variables stand for prepared statement commands. Their names refer to theCOM_ _`xxx`_ command set used in the network layer. In other words, their values increase whenever prepared statement API calls such asmysql_stmt_prepare(),mysql_stmt_execute(), and so forth are executed. However, Com_stmt_prepare,Com_stmt_execute andCom_stmt_close also increase forPREPARE,EXECUTE, orDEALLOCATE PREPARE, respectively. Additionally, the values of the older statement counter variables Com_prepare_sql,Com_execute_sql, andCom_dealloc_sql increase for thePREPARE,EXECUTE, andDEALLOCATE PREPARE statements.Com_stmt_fetch stands for the total number of network round-trips issued when fetching from cursors.
    Com_stmt_reprepare indicates the number of times statements were automatically reprepared by the server, for example, after metadata changes to tables or views referred to by the statement. A reprepare operation incrementsCom_stmt_reprepare, and alsoCom_stmt_prepare.
    Com_explain_other indicates the number ofEXPLAIN FOR CONNECTION statements executed. SeeSection 10.8.4, “Obtaining Execution Plan Information for a Named Connection”.
    Com_change_repl_filter indicates the number of CHANGE REPLICATION FILTER statements executed.
• Compression
  Whether the client connection uses compression in the client/server protocol.
  This status variable is deprecated; expect it to be removed in a future version of MySQL. SeeConfiguring Legacy Connection Compression.
• Compression_algorithm
  The name of the compression algorithm in use for the current connection to the server. The value can be any algorithm permitted in the value of theprotocol_compression_algorithms system variable. For example, the value isuncompressed if the connection does not use compression, or zlib if the connection uses the zlib algorithm.
  For more information, seeSection 6.2.8, “Connection Compression Control”.
• Compression_level
  The compression level in use for the current connection to the server. The value is 6 for zlib connections (the default zlib algorithm compression level), 1 to 22 for zstd connections, and 0 for uncompressed connections.
  For more information, seeSection 6.2.8, “Connection Compression Control”.
• Connection_errors_ xxx
  These variables provide information about errors that occur during the client connection process. They are global only and represent error counts aggregated across connections from all hosts. These variables track errors not accounted for by the host cache (see Section 7.1.12.3, “DNS Lookups and the Host Cache”), such as errors that are not associated with TCP connections, occur very early in the connection process (even before an IP address is known), or are not specific to any particular IP address (such as out-of-memory conditions).
  • Connection_errors_accept
    The number of errors that occurred during calls toaccept() on the listening port.
  • Connection_errors_internal
    The number of connections refused due to internal errors in the server, such as failure to start a new thread or an out-of-memory condition.
  • Connection_errors_max_connections
    The number of connections refused because the servermax_connections limit was reached.
  • Connection_errors_peer_address
    The number of errors that occurred while searching for connecting client IP addresses.
  • Connection_errors_select
    The number of errors that occurred during calls toselect() or poll() on the listening port. (Failure of this operation does not necessarily means a client connection was rejected.)
  • Connection_errors_tcpwrap
    The number of connections refused by thelibwrap library.
• Connections
  The number of connection attempts (successful or not) to the MySQL server.
• Created_tmp_disk_tables
  The number of internal on-disk temporary tables created by the server while executing statements.
  You can compare the number of internal on-disk temporary tables created to the total number of internal temporary tables created by comparingCreated_tmp_disk_tables andCreated_tmp_tables values.
  Note
  Due to a known limitation,Created_tmp_disk_tables does not count on-disk temporary tables created in memory-mapped files. By default, the TempTable storage engine overflow mechanism creates internal temporary tables in memory-mapped files. This behavior is controlled by thetemptable_use_mmap variable.
  See also Section 10.4.4, “Internal Temporary Table Use in MySQL”.
• Created_tmp_files
  How many temporary files mysqld has created.
• Created_tmp_tables
  The number of internal temporary tables created by the server while executing statements.
  You can compare the number of internal on-disk temporary tables created to the total number of internal temporary tables created by comparingCreated_tmp_disk_tables andCreated_tmp_tables values.
  See also Section 10.4.4, “Internal Temporary Table Use in MySQL”.
  Each invocation of the SHOW STATUS statement uses an internal temporary table and increments the globalCreated_tmp_tables value.
• Current_tls_ca
  The active ssl_ca value in the SSL context that the server uses for new connections. This context value may differ from the currentssl_ca system variable value if the system variable has been changed butALTER INSTANCE RELOAD TLS has not subsequently been executed to reconfigure the SSL context from the context-related system variable values and update the corresponding status variables. (This potential difference in values applies to each corresponding pair of context-related system and status variables. SeeServer-Side Runtime Configuration and Monitoring for Encrypted Connections.)
  TheCurrent_tls_ _`xxx`_ status variable values are also available through the Performance Schematls_channel_status table. SeeSection 29.12.22.9, “The tls_channel_status Table”.
• Current_tls_capath
  The active ssl_capath value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Current_tls_cert
  The active ssl_cert value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Current_tls_cipher
  The active ssl_cipher value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Current_tls_ciphersuites
  The active tls_ciphersuites value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Current_tls_crl
  The active ssl_crl value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
  Note
  When you reload the TLS context, OpenSSL reloads the file containing the CRL (certificate revocation list) as part of the process. If the CRL file is large, the server allocates a large chunk of memory (ten times the file size), which is doubled while the new instance is being loaded and the old one has not yet been released. The process resident memory is not immediately reduced after a large allocation is freed, so if you issue the ALTER INSTANCE RELOAD TLS statement repeatedly with a large CRL file, the process resident memory usage may grow as a result of this.
• Current_tls_crlpath
  The active ssl_crlpath value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Current_tls_key
  The active ssl_key value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Current_tls_version
  The active tls_version value in the TLS context that the server uses for new connections. For notes about the relationship between this status variable and its corresponding system variable, see the description ofCurrent_tls_ca.
• Delayed_errors
  This status variable is deprecated (becauseDELAYED inserts are not supported); expect it to be removed in a future release.
• Delayed_insert_threads
  This status variable is deprecated (becauseDELAYED inserts are not supported); expect it to be removed in a future release.
• Delayed_writes
  This status variable is deprecated (becauseDELAYED inserts are not supported); expect it to be removed in a future release.
• Deprecated_use_i_s_processlist_count
  How many times theinformation_schema.processlist table has been accessed since the last restart.
• Deprecated_use_i_s_processlist_last_timestamp
  A timestamp indicating the last time theinformation_schema.processlist table has been accessed since the last restart. Shows microseconds since the Unix Epoch.
• dragnet.Status
  The result of the most recent assignment to thedragnet.log_error_filter_rules system variable, empty if no such assignment has occurred.
• Error_log_buffered_bytes
  The number of bytes currently used in the Performance Schemaerror_log table. It is possible for the value to decrease, for example, if a new event cannot fit until discarding an old event, but the new event is smaller than the old one.
• Error_log_buffered_events
  The number of events currently present in the Performance Schema error_log table. As withError_log_buffered_bytes, it is possible for the value to decrease.
• Error_log_expired_events
  The number of events discarded from the Performance Schemaerror_log table to make room for new events.
• Error_log_latest_write
  The time of the last write to the Performance Schemaerror_log table.
• Flush_commands
  The number of times the server flushes tables, whether because a user executed a FLUSH TABLES statement or due to internal server operation. It is also incremented by receipt of a COM_REFRESH packet. This is in contrast toCom_flush, which indicates how many FLUSH statements have been executed, whether FLUSH TABLES, FLUSH LOGS, and so forth.
• Global_connection_memory
  The memory used by all user connections to the server. Memory used by system threads or by the MySQL root account is included in the total, but such threads or users are not subject to disconnection due to memory usage. This memory is not calculated unlessglobal_connection_memory_tracking is enabled (disabled by default). The Performance Schema must also be enabled.
  You can control (indirectly) the frequency with which this variable is updated by settingconnection_memory_chunk_size.
• Handler_commit
  The number of internal COMMIT statements.
• Handler_delete
  The number of times that rows have been deleted from tables.
• Handler_external_lock
  The server increments this variable for each call to itsexternal_lock() function, which generally occurs at the beginning and end of access to a table instance. There might be differences among storage engines. This variable can be used, for example, to discover for a statement that accesses a partitioned table how many partitions were pruned before locking occurred: Check how much the counter increased for the statement, subtract 2 (2 calls for the table itself), then divide by 2 to get the number of partitions locked.
• Handler_mrr_init
  The number of times the server uses a storage engine's own Multi-Range Read implementation for table access.
• Handler_prepare
  A counter for the prepare phase of two-phase commit operations.
• Handler_read_first
  The number of times the first entry in an index was read. If this value is high, it suggests that the server is doing a lot of full index scans (for example, SELECT col1 FROM foo, assuming that col1 is indexed).
• Handler_read_key
  The number of requests to read a row based on a key. If this value is high, it is a good indication that your tables are properly indexed for your queries.
• Handler_read_last
  The number of requests to read the last key in an index. WithORDER BY, the server issues a first-key request followed by several next-key requests, whereas withORDER BY DESC, the server issues a last-key request followed by several previous-key requests.
• Handler_read_next
  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.
• Handler_read_prev
  The number of requests to read the previous row in key order. This read method is mainly used to optimize ORDER BY ... DESC.
• Handler_read_rnd
  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. You probably have a lot of queries that require MySQL to scan entire tables or you have joins that do not use keys properly.
• Handler_read_rnd_next
  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. Generally this suggests that your tables are not properly indexed or that your queries are not written to take advantage of the indexes you have.
• Handler_rollback
  The number of requests for a storage engine to perform a rollback operation.
• Handler_savepoint
  The number of requests for a storage engine to place a savepoint.
• Handler_savepoint_rollback
  The number of requests for a storage engine to roll back to a savepoint.
• Handler_update
  The number of requests to update a row in a table.
• Handler_write
  The number of requests to insert a row in a table.
• Innodb_buffer_pool_dump_status
  The progress of an operation to record thepages held in theInnoDB buffer pool, triggered by the setting ofinnodb_buffer_pool_dump_at_shutdown orinnodb_buffer_pool_dump_now.
  For related information and examples, seeSection 17.8.3.6, “Saving and Restoring the Buffer Pool State”.
• Innodb_buffer_pool_load_status
  The progress of an operation towarm up theInnoDB buffer pool by reading in a set of pages corresponding to an earlier point in time, triggered by the setting ofinnodb_buffer_pool_load_at_startup orinnodb_buffer_pool_load_now. If the operation introduces too much overhead, you can cancel it by settinginnodb_buffer_pool_load_abort.
  For related information and examples, seeSection 17.8.3.6, “Saving and Restoring the Buffer Pool State”.
• Innodb_buffer_pool_bytes_data
  The total number of bytes in the InnoDB buffer pool containing data. The number includes bothdirty and clean pages. For more accurate memory usage calculations than withInnodb_buffer_pool_pages_data, when compressed tables cause the buffer pool to hold pages of different sizes.
• Innodb_buffer_pool_pages_data
  The number of pages in theInnoDB buffer pool containing data. The number includes bothdirty and clean pages. When using compressed tables, the reportedInnodb_buffer_pool_pages_data value may be larger thanInnodb_buffer_pool_pages_total (Bug #59550).
• Innodb_buffer_pool_bytes_dirty
  The total current number of bytes held indirty pages in theInnoDB buffer pool. For more accurate memory usage calculations than withInnodb_buffer_pool_pages_dirty, when compressed tables cause the buffer pool to hold pages of different sizes.
• Innodb_buffer_pool_pages_dirty
  The current number of dirty pages in the InnoDB buffer pool.
• Innodb_buffer_pool_pages_flushed
  The number of requests toflush pages from theInnoDB buffer pool.
• Innodb_buffer_pool_pages_free
  The number of free pages in the InnoDB buffer pool.
• Innodb_buffer_pool_pages_latched
  The number of latched pages in the InnoDB buffer pool. These are pages currently being read or written, or that cannot beflushed or removed for some other reason. Calculation of this variable is expensive, so it is available only when the UNIV_DEBUG system is defined at server build time.
• Innodb_buffer_pool_pages_misc
  The number of pages in theInnoDB buffer pool that are busy because they have been allocated for administrative overhead, such as row locks or theadaptive hash index. This value can also be calculated asInnodb_buffer_pool_pages_total −Innodb_buffer_pool_pages_free −Innodb_buffer_pool_pages_data. When using compressed tables,Innodb_buffer_pool_pages_misc may report an out-of-bounds value (Bug #59550).
• Innodb_buffer_pool_pages_total
  The total size of the InnoDB buffer pool, inpages. When usingcompressed tables, the reportedInnodb_buffer_pool_pages_data value may be larger thanInnodb_buffer_pool_pages_total (Bug #59550)
• Innodb_buffer_pool_read_ahead
  The number of pages read into the InnoDB buffer pool by theread-ahead background thread.
• Innodb_buffer_pool_read_ahead_evicted
  The number of pages read into the InnoDB buffer pool by theread-ahead background thread that were subsequentlyevicted without having been accessed by queries.
• Innodb_buffer_pool_read_ahead_rnd
  The number of “random” read-aheads initiated byInnoDB. This happens when a query scans a large portion of a table but in random order.
• Innodb_buffer_pool_read_requests
  The number of logical read requests.
• Innodb_buffer_pool_reads
  The number of logical reads that InnoDB could not satisfy from thebuffer pool, and had to read directly from disk.
• Innodb_buffer_pool_resize_status
  The status of an operation to resize theInnoDB buffer pool dynamically, triggered by setting theinnodb_buffer_pool_size parameter dynamically. Theinnodb_buffer_pool_size parameter is dynamic, which allows you to resize the buffer pool without restarting the server. SeeConfiguring InnoDB Buffer Pool Size Online for related information.
• Innodb_buffer_pool_resize_status_code
  Reports status codes for tracking online buffer pool resizing operations. Each status code represents a stage in a resizing operation. Status codes include:
  • 0: No Resize operation in progress
  • 1: Starting Resize
  • 2: Disabling AHI (Adaptive Hash Index)
  • 3: Withdrawing Blocks
  • 4: Acquiring Global Lock
  • 5: Resizing Pool
  • 6: Resizing Hash
  • 7: Resizing Failed
    You can use this status variable in conjunction withInnodb_buffer_pool_resize_status_progress to track the progress of each stage of a resizing operation. TheInnodb_buffer_pool_resize_status_progress variable reports a percentage value indicating the progress of the current stage.
    For more information, seeMonitoring Online Buffer Pool Resizing Progress.
• Innodb_buffer_pool_resize_status_progress
  Reports a percentage value indicating the progress of the current stage of an online buffer pool resizing operation. This variable is used in conjunction withInnodb_buffer_pool_resize_status_code, which reports a status code indicating the current stage of an online buffer pool resizing operation.
  The percentage value is updated after each buffer pool instance is processed. As the status code (reported byInnodb_buffer_pool_resize_status_code) changes from one status to another, the percentage value is reset to 0.
  For related information, seeMonitoring Online Buffer Pool Resizing Progress.
• Innodb_buffer_pool_wait_free
  Normally, writes to the InnoDB buffer pool happen in the background. When InnoDB needs to read or create a page and no clean pages are available, InnoDB flushes somedirty pages first and waits for that operation to finish. This counter counts instances of these waits. Ifinnodb_buffer_pool_size has been set properly, this value should be small.
• Innodb_buffer_pool_write_requests
  The number of writes done to the InnoDB buffer pool.
• Innodb_data_fsyncs
  The number of fsync() operations so far. The frequency of fsync() calls is influenced by the setting of theinnodb_flush_method configuration option.
  Counts the number of fdatasync() operations if innodb_use_fdatasync is enabled.
• Innodb_data_pending_fsyncs
  The current number of pending fsync() operations. The frequency of fsync() calls is influenced by the setting of theinnodb_flush_method configuration option.
• Innodb_data_pending_reads
  The current number of pending reads.
• Innodb_data_pending_writes
  The current number of pending writes.
• Innodb_data_read
  The amount of data read since the server was started (in bytes).
• Innodb_data_reads
  The total number of data reads (OS file reads).
• Innodb_data_writes
  The total number of data writes.
• Innodb_data_written
  The amount of data written so far, in bytes.
• Innodb_dblwr_pages_written
  The number of pages that have been written to thedoublewrite buffer. See Section 17.11.1, “InnoDB Disk I/O”.
• Innodb_dblwr_writes
  The number of doublewrite operations that have been performed. See Section 17.11.1, “InnoDB Disk I/O”.
• Innodb_have_atomic_builtins
  Indicates whether the server was built withatomic instructions.
• Innodb_log_waits
  The number of times that thelog buffer was too small and a wait was required for it to be flushed before continuing.
• Innodb_log_write_requests
  The number of write requests for the InnoDB redo log.
• Innodb_log_writes
  The number of physical writes to the InnoDB redo log file.
• Innodb_num_open_files
  The number of files InnoDB currently holds open.
• Innodb_os_log_fsyncs
  The number of fsync() writes done to theInnoDB redo log files.
• Innodb_os_log_pending_fsyncs
  The number of pending fsync() operations for the InnoDB redo log files.
• Innodb_os_log_pending_writes
  The number of pending writes to the InnoDB redo log files.
• Innodb_os_log_written
  The number of bytes written to the InnoDB redo log files.
• Innodb_page_size
  InnoDB page size (default 16KB). Many values are counted in pages; the page size enables them to be easily converted to bytes.
• Innodb_pages_created
  The number of pages created by operations onInnoDB tables.
• Innodb_pages_read
  The number of pages read from the InnoDB buffer pool by operations on InnoDB tables.
• Innodb_pages_written
  The number of pages written by operations onInnoDB tables.
• Innodb_redo_log_enabled
  Whether redo logging is enabled or disabled. SeeDisabling Redo Logging.
• Innodb_redo_log_capacity_resized
  The total redo log capacity for all redo log files, in bytes, after the last completed capacity resize operation. The value includes ordinary and spare redo log files.
  If there is no pending resize down operation,Innodb_redo_log_capacity_resized should be equal to theinnodb_redo_log_capacity setting if it's used, or it's ((innodb_log_files_in_group * innodb_log_file_size)) if those are used instead. See theinnodb_redo_log_capacity documentation for further clarification. Resize up operations are instantaneous.
  For related information, seeSection 17.6.5, “Redo Log”.
• Innodb_redo_log_checkpoint_lsn
  The redo log checkpoint LSN. For related information, seeSection 17.6.5, “Redo Log”.
• Innodb_redo_log_current_lsn
  The current LSN represents the last written position in the redo log buffer. InnoDB writes data to the redo log buffer inside the MySQL process before requesting that the operating system write the data to the current redo log file. For related information, seeSection 17.6.5, “Redo Log”.
• Innodb_redo_log_flushed_to_disk_lsn
  The flushed-to-disk LSN. InnoDB first writes data to the redo log and then requests that the operating system flush the data to disk. The flushed-to-disk LSN represents the last position in the redo log thatInnoDB knows has been flushed to disk. For related information, see Section 17.6.5, “Redo Log”.
• Innodb_redo_log_logical_size
  A data size value, in bytes, representing the LSN range containing in-use redo log data, spanning from the oldest block required by redo log consumers to the latest written block. For related information, seeSection 17.6.5, “Redo Log”.
• Innodb_redo_log_physical_size
  The amount of disk space in bytes currently consumed by all redo log files on disk, excluding spare redo log files. For related information, see Section 17.6.5, “Redo Log”.
• Innodb_redo_log_read_only
  Whether the redo log is read-only.
• Innodb_redo_log_resize_status
  The redo log resize status indicating the current state of the redo log capacity resize mechanism. Possible values include:
  • OK: There are no issues and no pending redo log capacity resize operations.
  • Resizing down: A resize down operation is in progress.
    A resize up operation is instantaneous and therefore has no pending status.
• Innodb_redo_log_uuid
  The redo log UUID.
• Innodb_row_lock_current_waits
  The number of row locks currently waited for by operations onInnoDB tables.
• Innodb_row_lock_time
  The total time spent in acquiringrow locks forInnoDB tables, in milliseconds.
• Innodb_row_lock_time_avg
  The average time to acquire arow lock forInnoDB tables, in milliseconds.
• Innodb_row_lock_time_max
  The maximum time to acquire arow lock forInnoDB tables, in milliseconds.
• Innodb_row_lock_waits
  The number of times operations on InnoDB tables had to wait for a row lock.
• Innodb_rows_deleted
  The number of rows deleted from InnoDB tables.
• Innodb_rows_inserted
  The number of rows inserted into InnoDB tables.
• Innodb_rows_read
  The number of rows read from InnoDB tables.
• Innodb_rows_updated
  The estimated number of rows updated inInnoDB tables.
  Note
  This value is not meant to be 100% accurate. For an accurate (but more expensive) result, useROW_COUNT().
• Innodb_system_rows_deleted
  The number of rows deleted from InnoDB tables belonging to system-created schemas.
• Innodb_system_rows_inserted
  The number of rows inserted into InnoDB tables belonging to system-created schemas.
• Innodb_system_rows_updated
  The number of rows updated in InnoDB tables belonging to system-created schemas.
• Innodb_system_rows_read
  The number of rows read from InnoDB tables belonging to system-created schemas.
• Innodb_truncated_status_writes
  The number of times output from the SHOW ENGINE INNODB STATUS statement has been truncated.
• Innodb_undo_tablespaces_active
  The number of active undo tablespaces. Includes both implicit (InnoDB-created) and explicit (user-created) undo tablespaces. For information about undo tablespaces, see Section 17.6.3.4, “Undo Tablespaces”.
• Innodb_undo_tablespaces_explicit
  The number of user-created undo tablespaces. For information about undo tablespaces, seeSection 17.6.3.4, “Undo Tablespaces”.
• Innodb_undo_tablespaces_implicit
  The number of undo tablespaces created byInnoDB. Two default undo tablespaces are created by InnoDB when the MySQL instance is initialized. For information about undo tablespaces, seeSection 17.6.3.4, “Undo Tablespaces”.
• Innodb_undo_tablespaces_total
  The total number of undo tablespaces. Includes both implicit (InnoDB-created) and explicit (user-created) undo tablespaces, active and inactive. For information about undo tablespaces, seeSection 17.6.3.4, “Undo Tablespaces”.
• Key_blocks_not_flushed
  The number of key blocks in the MyISAM key cache that have changed but have not yet been flushed to disk.
• Key_blocks_unused
  The number of unused blocks in the MyISAM key cache. You can use this value to determine how much of the key cache is in use; see the discussion ofkey_buffer_size inSection 7.1.8, “Server System Variables”.
• Key_blocks_used
  The number of used blocks in the MyISAM key cache. This value is a high-water mark that indicates the maximum number of blocks that have ever been in use at one time.
• Key_read_requests
  The number of requests to read a key block from theMyISAM key cache.
• Key_reads
  The number of physical reads of a key block from disk into theMyISAM key cache. IfKey_reads is large, then your key_buffer_size value is probably too small. The cache miss rate can be calculated asKey_reads/Key_read_requests.
• Key_write_requests
  The number of requests to write a key block to theMyISAM key cache.
• Key_writes
  The number of physical writes of a key block from theMyISAM key cache to disk.
• Last_query_cost
  The total cost of the last compiled query as computed by the query optimizer. This is useful for comparing the cost of different query plans for the same query. The default value of 0 means that no query has been compiled yet. The default value is 0. Last_query_cost has session scope.
  This variable shows the cost of queries that have multiple query blocks, summing the cost estimates of each query block, estimating how many times non-cacheable subqueries are executed, and multiplying the cost of those query blocks by the number of subquery executions.
• Last_query_partial_plans
  The number of iterations the query optimizer made in execution plan construction for the previous query.
  Last_query_partial_plans has session scope.
• Locked_connects
  The number of attempts to connect to locked user accounts. For information about account locking and unlocking, seeSection 8.2.20, “Account Locking”.
• Max_execution_time_exceeded
  The number of SELECT statements for which the execution timeout was exceeded.
• Max_execution_time_set
  The number of SELECT statements for which a nonzero execution timeout was set. This includes statements that include a nonzeroMAX_EXECUTION_TIME optimizer hint, and statements that include no such hint but execute while the timeout indicated by themax_execution_time system variable is nonzero.
• Max_execution_time_set_failed
  The number of SELECT statements for which the attempt to set an execution timeout failed.
• Max_used_connections
  The maximum number of connections that have been in use simultaneously since the server started.
• Max_used_connections_time
  The time at whichMax_used_connections reached its current value.
• Not_flushed_delayed_rows
  This status variable is deprecated (becauseDELAYED inserts are not supported); expect it to be removed in a future release.
• mecab_charset
  The character set currently used by the MeCab full-text parser plugin. For related information, seeSection 14.9.9, “MeCab Full-Text Parser Plugin”.
• Ongoing_anonymous_transaction_count
  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.
• Ongoing_anonymous_gtid_violating_transaction_count
  This status variable is only available in debug builds. Shows the number of ongoing transactions which usegtid_next=ANONYMOUS and that violate GTID consistency.
• Ongoing_automatic_gtid_violating_transaction_count
  This status variable is only available in debug builds. Shows the number of ongoing transactions which usegtid_next=AUTOMATIC and that violate GTID consistency.
• Open_files
  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. Also, the count does not include files that storage engines open using their own internal functions rather than asking the server level to do so.
• Open_streams
  The number of streams that are open (used mainly for logging).
• Open_table_definitions
  The number of cached table definitions.
• Open_tables
  The number of tables that are open.
• Opened_files
  The number of files that have been opened withmy_open() (a mysys library function). Parts of the server that open files without using this function do not increment the count.
• Opened_table_definitions
  The number of table definitions that have been cached.
• Opened_tables
  The number of tables that have been opened. IfOpened_tables is big, yourtable_open_cache value is probably too small.
• Performance_schema_ _`xxx`_
  Performance Schema status variables are listed inSection 29.16, “Performance Schema Status Variables”. These variables provide information about instrumentation that could not be loaded or created due to memory constraints.
• Prepared_stmt_count
  The current number of prepared statements. (The maximum number of statements is given by themax_prepared_stmt_count system variable.)
• Queries
  The number of statements executed by the server. This variable includes statements executed within stored programs, unlike the Questions variable. It does not count COM_PING orCOM_STATISTICS commands.
  The discussion at the beginning of this section indicates how to relate this statement-counting status variable to other such variables.
• Questions
  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 theQueries variable. This variable does not count COM_PING,COM_STATISTICS,COM_STMT_PREPARE,COM_STMT_CLOSE, orCOM_STMT_RESET commands.
  The discussion at the beginning of this section indicates how to relate this statement-counting status variable to other such variables.
• Replica_open_temp_tables
  Replica_open_temp_tables shows the number of temporary tables that the replication SQL thread currently has open. If the value is greater than zero, it is not safe to shut down the replica; seeSection 19.5.1.31, “Replication and Temporary Tables”. This variable reports the total count of open temporary tables for_all_ replication channels.
• Resource_group_supported
  Indicates whether the resource group feature is supported.
  On some platforms or MySQL server configurations, resource groups are unavailable or have limitations. In particular, Linux systems might require a manual step for some installation methods. For details, seeResource Group Restrictions.
• Rpl_semi_sync_master_clients
  The number of semisynchronous replicas.
  Deprecated synonym forRpl_semi_sync_source_clients.
• Rpl_semi_sync_master_net_avg_wait_time
  Deprecated synonym forRpl_semi_sync_source_net_avg_wait_time.
• Rpl_semi_sync_master_net_wait_time
  Deprecated synonym forRpl_semi_sync_source_net_wait_time.
• Rpl_semi_sync_master_net_waits
  The total number of times the source waited for replica replies.
  Deprecated synonym forRpl_semi_sync_source_net_waits.
• Rpl_semi_sync_master_no_times
  Deprecated synonym forRpl_semi_sync_source_no_times.
• Rpl_semi_sync_master_no_tx
  Deprecated synonym forRpl_semi_sync_source_no_tx.
• Rpl_semi_sync_master_status
  Deprecated synonym forRpl_semi_sync_source_status.
• Rpl_semi_sync_master_timefunc_failures
  Deprecated synonym forRpl_semi_sync_source_timefunc_failures.
• Rpl_semi_sync_master_tx_avg_wait_time
  Deprecated synonym forRpl_semi_sync_source_tx_avg_wait_time.
• Rpl_semi_sync_master_tx_wait_time
  Deprecated synonym forRpl_semi_sync_source_tx_wait_time.
• Rpl_semi_sync_master_tx_waits
  Deprecated synonym forRpl_semi_sync_source_tx_waits.
• Rpl_semi_sync_master_wait_pos_backtraverse
  Deprecated synonym forRpl_semi_sync_source_wait_pos_backtraverse.
• Rpl_semi_sync_master_wait_sessions
  Deprecated synonym forRpl_semi_sync_source_wait_sessions.
• Rpl_semi_sync_master_yes_tx
  Deprecated synonym forRpl_semi_sync_source_yes_tx.
• Rpl_semi_sync_source_clients
  The number of semisynchronous replicas.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_net_avg_wait_time
  The average time in microseconds the source waited for a replica reply. This variable is always 0, and is deprecated; expect it to be removed in a future version.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_net_wait_time
  The total time in microseconds the source waited for replica replies. This variable is always 0, and is deprecated; expect it to be removed in a future version.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_net_waits
  The total number of times the source waited for replica replies.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_no_times
  The number of times the source turned off semisynchronous replication.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_no_tx
  The number of commits that were not acknowledged successfully by a replica.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_status
  Whether semisynchronous replication currently is operational on the source. The value is ON if the plugin has been enabled and a commit acknowledgment has occurred. It is OFF if the plugin is not enabled or the source has fallen back to asynchronous replication due to commit acknowledgment timeout.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_timefunc_failures
  The number of times the source failed when calling time functions such as gettimeofday().
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_tx_avg_wait_time
  The average time in microseconds the source waited for each transaction.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_tx_wait_time
  The total time in microseconds the source waited for transactions.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_tx_waits
  The total number of times the source waited for transactions.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_wait_pos_backtraverse
  The total number of times the source waited for an event with binary coordinates lower than events waited for previously. This can occur when the order in which transactions start waiting for a reply is different from the order in which their binary log events are written.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_wait_sessions
  The number of sessions currently waiting for replica replies.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_source_yes_tx
  The number of commits that were acknowledged successfully by a replica.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_replica_status
  Shows whether semisynchronous replication is currently operational on the replica. This is ON if the plugin has been enabled and the replication I/O (receiver) thread is running, OFF otherwise.
  Available when the rpl_semi_sync_source plugin (semisync_source.so library) is installed on the source.
• Rpl_semi_sync_slave_status
  Deprecated synonym forRpl_semi_sync_replica_status.
• Rsa_public_key
  The value of this variable is the public key used by thesha256_password (deprecated) authentication plugin for RSA key pair-based password exchange. The value is nonempty only if the server successfully initializes the private and public keys in the files named by thesha256_password_private_key_path andsha256_password_public_key_path system variables. The value ofRsa_public_key comes from the latter file.
  For information about sha256_password, seeSection 8.4.1.3, “SHA-256 Pluggable Authentication”.
• Secondary_engine_execution_count
  The number of queries offloaded to a secondary engine.
  For use with HeatWave. See HeatWave User Guide.
• Select_full_join
  The number of joins that perform table scans because they do not use indexes. If this value is not 0, you should carefully check the indexes of your tables.
• Select_full_range_join
  The number of joins that used a range search on a reference table.
• Select_range
  The number of joins that used ranges on the first table. This is normally not a critical issue even if the value is quite large.
• Select_range_check
  The number of joins without keys that check for key usage after each row. If this is not 0, you should carefully check the indexes of your tables.
• Select_scan
  The number of joins that did a full scan of the first table.
• Slave_open_temp_tables
  Deprecated alias forReplica_open_temp_tables.
• Slave_rows_last_search_algorithm_used
  Deprecated alias forReplica_rows_last_search_algorithm_used.
• Slow_launch_threads
  The number of threads that have taken more thanslow_launch_time seconds to create.
• Slow_queries
  The number of queries that have taken more thanlong_query_time seconds. This counter increments regardless of whether the slow query log is enabled. For information about that log, seeSection 7.4.5, “The Slow Query Log”.
• Sort_merge_passes
  The number of merge passes that the sort algorithm has had to do. If this value is large, you should consider increasing the value of the sort_buffer_size system variable.
• Sort_range
  The number of sorts that were done using ranges.
• Sort_rows
  The number of sorted rows.
• Sort_scan
  The number of sorts that were done by scanning the table.
• Ssl_accept_renegotiates
  The number of negotiates needed to establish the connection.
• Ssl_accepts
  The number of accepted SSL connections.
• Ssl_callback_cache_hits
  The number of callback cache hits.
• Ssl_cipher
  The current encryption cipher (empty for unencrypted connections).
• Ssl_cipher_list
  The list of possible SSL ciphers (empty for non-SSL connections). If MySQL supports TLSv1.3, the value includes the possible TLSv1.3 ciphersuites. SeeSection 8.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
• Ssl_client_connects
  The number of SSL connection attempts to an SSL-enabled replication source server.
• Ssl_connect_renegotiates
  The number of negotiates needed to establish the connection to an SSL-enabled replication source server.
• Ssl_ctx_verify_depth
  The SSL context verification depth (how many certificates in the chain are tested).
• Ssl_ctx_verify_mode
  The SSL context verification mode.
• Ssl_default_timeout
  The default SSL timeout.
• Ssl_finished_accepts
  The number of successful SSL connections to the server.
• Ssl_finished_connects
  The number of successful replica connections to an SSL-enabled replication source server.
• Ssl_server_not_after
  The last date for which the SSL certificate is valid. To check SSL certificate expiration information, use this statement:

mysql> SHOW STATUS LIKE 'Ssl_server_not%';  
+-----------------------+--------------------------+  
| Variable_name         | Value                    |  
+-----------------------+--------------------------+  
| Ssl_server_not_after  | Apr 28 14:16:39 2025 GMT |  
| Ssl_server_not_before | May  1 14:16:39 2015 GMT |  
+-----------------------+--------------------------+  

• Ssl_server_not_before
  The first date for which the SSL certificate is valid.
• Ssl_session_cache_hits
  The number of SSL session cache hits.
• Ssl_session_cache_misses
  The number of SSL session cache misses.
• Ssl_session_cache_mode
  The SSL session cache mode. When the value of thessl_session_cache_mode server variable is ON, the value of theSsl_session_cache_mode status variable is SERVER.
• Ssl_session_cache_overflows
  The number of SSL session cache overflows.
• Ssl_session_cache_size
  The SSL session cache size.
• Ssl_session_cache_timeout
  The timeout value in seconds of SSL sessions in the cache.
• Ssl_session_cache_timeouts
  The number of SSL session cache timeouts.
• Ssl_sessions_reused
  This is equal to 0 if TLS was not used in the current MySQL session, or if a TLS session has not been reused; otherwise it is equal to 1.
  Ssl_sessions_reused has session scope.
• Ssl_used_session_cache_entries
  How many SSL session cache entries were used.
• Ssl_verify_depth
  The verification depth for replication SSL connections.
• Ssl_verify_mode
  The verification mode used by the server for a connection that uses SSL. The value is a bitmask; bits are defined in theopenssl/ssl.h header file:

# define SSL_VERIFY_NONE                 0x00  
# define SSL_VERIFY_PEER                 0x01  
# define SSL_VERIFY_FAIL_IF_NO_PEER_CERT 0x02  
# define SSL_VERIFY_CLIENT_ONCE          0x04  

SSL_VERIFY_PEER indicates that the server asks for a client certificate. If the client supplies one, the server performs verification and proceeds only if verification is successful. SSL_VERIFY_CLIENT_ONCE indicates that a request for the client certificate is performed only in the initial handshake.

• Ssl_version
  The SSL protocol version of the connection (for example, TLSv1.2). If the connection is not encrypted, the value is empty.
• Table_locks_immediate
  The number of times that a request for a table lock could be granted immediately.
• Table_locks_waited
  The number of times that a request for a table lock could not be granted immediately and a wait was needed. If this is high and you have performance problems, you should first optimize your queries, and then either split your table or tables or use replication.
• Table_open_cache_hits
  The number of hits for open tables cache lookups.
• Table_open_cache_misses
  The number of misses for open tables cache lookups.
• Table_open_cache_overflows
  The number of overflows for the open tables cache. This is the number of times, after a table is opened or closed, a cache instance has an unused entry and the size of the instance is larger than table_open_cache / table_open_cache_instances.
• Tc_log_max_pages_used
  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. If the product ofTc_log_max_pages_used andTc_log_page_size is always significantly less than the log size, the size is larger than necessary and can be reduced. (The size is set by the--log-tc-size option. This variable is unused: It is unneeded for binary log-based recovery, and the memory-mapped recovery log method is not used unless the number of storage engines that are capable of two-phase commit and that support XA transactions is greater than one. (InnoDB is the only applicable engine.)
• Tc_log_page_size
  The page size used for the memory-mapped implementation of the XA recovery log. The default value is determined usinggetpagesize(). This variable is unused for the same reasons as described forTc_log_max_pages_used.
• Tc_log_page_waits
  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. If this value is large, you might want to increase the log size (with the--log-tc-size option). For binary log-based recovery, this variable increments each time the binary log cannot be closed because there are two-phase commits in progress. (The close operation waits until all such transactions are finished.)
• Telemetry_metrics_supported
  Whether server telemetry metrics is supported.
  For more information, see the Server telemetry metrics service section in the MySQL Source Code documentation.
• telemetry.live_sessions
  Displays the current number of sessions instrumented with telemetry. This can be useful when unloading the Telemetry component, to monitor how many sessions are blocking the unload operation.
  For more information, see the Server telemetry traces service section in the MySQL Source Code documentation and Chapter 35, Telemetry.
• Telemetry_traces_supported
  Whether server telemetry traces is supported.
  For more information, see the Server telemetry traces service section in the MySQL Source Code documentation.
• Threads_cached
  The number of threads in the thread cache.
• Threads_connected
  The number of currently open connections.
• Threads_created
  The number of threads created to handle connections. IfThreads_created is big, you may want to increase thethread_cache_size value. The cache miss rate can be calculated asThreads_created/Connections.
• Threads_running
  The number of threads that are not sleeping.
• Tls_library_version
  The runtime version of the OpenSSL library that is in use for this MySQL instance.
• Tls_sni_server_name
  The Server Name Indication (SNI) that is in use for this session, if specified by the client; otherwise, empty. SNI is an extension to the TLS protocol (OpenSSL must be compiled using TLS extensions for this status variable to function). The MySQL implementation of SNI represents the client-side only.
• Uptime
  The number of seconds that the server has been up.
• Uptime_since_flush_status
  The number of seconds since the most recent FLUSH STATUS statement.