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 13.7.7.37, “SHOW STATUS Statement”). The optional GLOBAL keyword aggregates the values over all connections, and SESSION shows the values for the current connection.
mysql> SHOW GLOBAL STATUS;
+-----------------------------------+------------+
| Variable_name | Value |
+-----------------------------------+------------+
| Aborted_clients | 0 |
| Aborted_connects | 0 |
| Bytes_received | 155372598 |
| Bytes_sent | 1176560426 |
...
| Connections | 30023 |
| Created_tmp_disk_tables | 0 |
| Created_tmp_files | 3 |
| Created_tmp_tables | 2 |
...
| Threads_created | 217 |
| Threads_running | 88 |
| Uptime | 1389872 |
+-----------------------------------+------------+
Many status variables are reset to 0 by the FLUSH STATUS statement.
This section provides a description of each status variable. For a status variable summary, see Section 5.1.6, “Server Status Variable Reference”. For information about status variables specific to NDB Cluster, see Section 23.3.3.9.3, “NDB Cluster Status Variables”.
The status variables have the following meanings.
The number of connections that were aborted because the client died without closing the connection properly. See Section B.3.2.9, “Communication Errors and Aborted Connections”.
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 the Connection_errors_ status variables and the xxxhost_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. The Authentication_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"
This variable was added in MySQL 8.0.21.
The number of transactions that used the temporary binary log cache but that exceeded the value of binlog_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 the Binlog_stmt_cache_disk_use status variable.
The number of cached privilege objects. Each object is the privilege combination of a user and its active roles.
The number of transactions that used the binary log cache.
The number of nontransaction statements that used the binary log statement cache but that exceeded the value of binlog_stmt_cache_size and used a temporary file to store those statements.
The number of nontransactional statements that used the binary log statement cache.
The number of bytes received from all clients.
The number of bytes sent to all clients.
Caching_sha2_password_rsa_public_key
The public key used by the caching_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 the caching_sha2_password_private_key_path and caching_sha2_password_public_key_path system variables. The value of Caching_sha2_password_rsa_public_key comes from the latter file.
The Com_ statement counter variables indicate the number of times each xxxxxx statement has been executed. There is one status variable for each type of statement. For example, Com_delete and Com_update count DELETE and UPDATE statements, respectively. Com_delete_multi and Com_update_multi are similar but apply to DELETE and UPDATE statements that use multiple-table syntax.
All Com_stmt_ 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, the xxxCom_restart and Com_shutdown variables that track RESTART and SHUTDOWN statements normally have a value of zero, but can be nonzero if RESTART or SHUTDOWN statements were executed but failed.
The Com_stmt_ status variables are as follows:xxx
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 the COM_ command set used in the network layer. In other words, their values increase whenever prepared statement API calls such as mysql_stmt_prepare(), mysql_stmt_execute(), and so forth are executed. However, xxxCom_stmt_prepare, Com_stmt_execute and Com_stmt_close also increase for PREPARE, EXECUTE, or DEALLOCATE PREPARE, respectively. Additionally, the values of the older statement counter variables Com_prepare_sql, Com_execute_sql, and Com_dealloc_sql increase for the PREPARE, EXECUTE, and DEALLOCATE 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 increments Com_stmt_reprepare, and also Com_stmt_prepare.
Com_explain_other indicates the number of EXPLAIN FOR CONNECTION statements executed. See Section 8.8.4, “Obtaining Execution Plan Information for a Named Connection”.
Com_change_repl_filter indicates the number of CHANGE REPLICATION FILTER statements executed.
Whether the client connection uses compression in the client/server protocol.
As of MySQL 8.0.18, this status variable is deprecated; expect it to be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
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 the protocol_compression_algorithms system variable. For example, the value is uncompressed if the connection does not use compression, or zlib if the connection uses the zlib algorithm.
For more information, see Section 4.2.8, “Connection Compression Control”.
This variable was added in MySQL 8.0.18.
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, see Section 4.2.8, “Connection Compression Control”.
This variable was added in MySQL 8.0.18.
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 5.1.12.3, “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).
The number of errors that occurred during calls to accept() on the listening port.
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 server max_connections limit was reached.
Connection_errors_peer_address
The number of errors that occurred while searching for connecting client IP addresses.
The number of errors that occurred during calls to select() or poll() on the listening port. (Failure of this operation does not necessarily means a client connection was rejected.)
The number of connections refused by the libwrap library.
The number of connection attempts (successful or not) to the MySQL server.
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 comparing Created_tmp_disk_tables and Created_tmp_tables values.
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 the temptable_use_mmap variable, which is enabled by default.
See also Section 8.4.4, “Internal Temporary Table Use in MySQL”.
How many temporary files mysqld has created.
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 comparing Created_tmp_disk_tables and Created_tmp_tables values.
See also Section 8.4.4, “Internal Temporary Table Use in MySQL”.
Each invocation of the SHOW STATUS statement uses an internal temporary table and increments the global Created_tmp_tables value.
The active ssl_ca value in the SSL context that the server uses for new connections. This context value may differ from the current ssl_ca system variable value if the system variable has been changed but ALTER 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. See Server-Side Runtime Configuration and Monitoring for Encrypted Connections.)
This variable was added in MySQL 8.0.16.
As of MySQL 8.0.21, the Current_tls_ status variable values are also available through the Performance Schema xxxtls_channel_status table. See Section 27.12.21.7, “The tls_channel_status Table”.
The active ssl_capath value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active ssl_cert value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active ssl_cipher value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active tls_ciphersuites value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active ssl_crl value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active ssl_crlpath value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active ssl_key value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
The active tls_version value in the TSL 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 of Current_tls_ca.
This variable was added in MySQL 8.0.16.
This status variable is deprecated (because DELAYED inserts are not supported); expect it to be removed in a future release.
This status variable is deprecated (because DELAYED inserts are not supported); expect it to be removed in a future release.
This status variable is deprecated (because DELAYED inserts are not supported); expect it to be removed in a future release.
The result of the most recent assignment to the dragnet.log_error_filter_rules system variable, empty if no such assignment has occurred.
This variable was added in MySQL 8.0.12.
The number of bytes currently used in the Performance Schema error_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.
This variable was added in MySQL 8.0.22.
The number of events currently present in the Performance Schema error_log table. As with Error_log_buffered_bytes, it is possible for the value to decrease.
This variable was added in MySQL 8.0.22.
The number of events discarded from the Performance Schema error_log table to make room for new events.
This variable was added in MySQL 8.0.22.
The time of the last write to the Performance Schema error_log table.
This variable was added in MySQL 8.0.22.
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 to Com_flush, which indicates how many FLUSH statements have been executed, whether FLUSH TABLES, FLUSH LOGS, and so forth.
group_replication_primary_member
Shows the primary member's UUID when the group is operating in single-primary mode. If the group is operating in multi-primary mode, shows an empty string.
The group_replication_primary_member status variable is deprecated and is scheduled to be removed in a future version.
The number of internal COMMIT statements.
The number of times that rows have been deleted from tables.
The server increments this variable for each call to its external_lock() function, which generally occurs at the beginning and end of access to a table instance. 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.
The number of times the server uses a storage engine's own Multi-Range Read implementation for table access.
A counter for the prepare phase of two-phase commit operations.
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).
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.
The number of requests to read the last key in an index. With ORDER BY, the server issues a first-key request followed by several next-key requests, whereas with ORDER BY DESC, the server issues a last-key request followed by several previous-key requests.
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.
The number of requests to read the previous row in key order. This read method is mainly used to optimize ORDER BY ... DESC.
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.
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.
The number of requests for a storage engine to perform a rollback operation.
The number of requests for a storage engine to place a savepoint.
The number of requests for a storage engine to roll back to a savepoint.
The number of requests to update a row in a table.
The number of requests to insert a row in a table.
Innodb_buffer_pool_dump_status
The progress of an operation to record the pages held in the InnoDB buffer pool, triggered by the setting of innodb_buffer_pool_dump_at_shutdown or innodb_buffer_pool_dump_now.
For related information and examples, see Section 15.8.3.6, “Saving and Restoring the Buffer Pool State”.
Innodb_buffer_pool_load_status
The progress of an operation to warm up the InnoDB buffer pool by reading in a set of pages corresponding to an earlier point in time, triggered by the setting of innodb_buffer_pool_load_at_startup or innodb_buffer_pool_load_now. If the operation introduces too much overhead, you can cancel it by setting innodb_buffer_pool_load_abort.
For related information and examples, see Section 15.8.3.6, “Saving and Restoring the Buffer Pool State”.
The total number of bytes in the InnoDB buffer pool containing data. The number includes both dirty and clean pages. For more accurate memory usage calculations than with Innodb_buffer_pool_pages_data, when compressed tables cause the buffer pool to hold pages of different sizes.
The number of pages in the InnoDB buffer pool containing data. The number includes both dirty and clean pages. When using compressed tables, the reported Innodb_buffer_pool_pages_data value may be larger than Innodb_buffer_pool_pages_total (Bug #59550).
Innodb_buffer_pool_bytes_dirty
The total current number of bytes held in dirty pages in the InnoDB buffer pool. For more accurate memory usage calculations than with Innodb_buffer_pool_pages_dirty, when compressed tables cause the buffer pool to hold pages of different sizes.
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 to flush pages from the InnoDB buffer pool.
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 be flushed 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.
The number of pages in the InnoDB buffer pool that are busy because they have been allocated for administrative overhead, such as row locks or the adaptive hash index. This value can also be calculated as Innodb_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, in pages. When using compressed tables, the reported Innodb_buffer_pool_pages_data value may be larger than Innodb_buffer_pool_pages_total (Bug #59550)
The number of pages read into the InnoDB buffer pool by the read-ahead background thread.
Innodb_buffer_pool_read_ahead_evicted
The number of pages read into the InnoDB buffer pool by the read-ahead background thread that were subsequently evicted without having been accessed by queries.
Innodb_buffer_pool_read_ahead_rnd
The number of “random” read-aheads initiated by InnoDB. 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.
The number of logical reads that InnoDB could not satisfy from the buffer pool, and had to read directly from disk.
Innodb_buffer_pool_resize_status
The status of an operation to resize the InnoDB buffer pool dynamically, triggered by setting the innodb_buffer_pool_size parameter dynamically. The innodb_buffer_pool_size parameter is dynamic, which allows you to resize the buffer pool without restarting the server. See Configuring InnoDB Buffer Pool Size Online for related information.
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 some dirty pages first and waits for that operation to finish. This counter counts instances of these waits. If innodb_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.
The number of fsync() operations so far. The frequency of fsync() calls is influenced by the setting of the innodb_flush_method configuration option.
The current number of pending fsync() operations. The frequency of fsync() calls is influenced by the setting of the innodb_flush_method configuration option.
The current number of pending reads.
The current number of pending writes.
The amount of data read since the server was started (in bytes).
The total number of data reads (OS file reads).
The total number of data writes.
The amount of data written so far, in bytes.
The number of pages that have been written to the doublewrite buffer. See Section 15.11.1, “InnoDB Disk I/O”.
The number of doublewrite operations that have been performed. See Section 15.11.1, “InnoDB Disk I/O”.
Indicates whether the server was built with atomic instructions.
The number of times that the log buffer was too small and a wait was required for it to be flushed before continuing.
The number of write requests for the InnoDB redo log.
The number of physical writes to the InnoDB redo log file.
The number of files InnoDB currently holds open.
The number of fsync() writes done to the InnoDB redo log files.
The number of pending fsync() operations for the InnoDB redo log files.
The number of pending writes to the InnoDB redo log files.
The number of bytes written to the InnoDB redo log files.
InnoDB page size (default 16KB). Many values are counted in pages; the page size enables them to be easily converted to bytes.
The number of pages created by operations on InnoDB tables.
The number of pages read from the InnoDB buffer pool by operations on InnoDB tables.
The number of pages written by operations on InnoDB tables.
Whether redo logging is enabled or disabled. Introduced in MySQL 8.0.21.
The number of row locks currently being waited for by operations on InnoDB tables.
The total time spent in acquiring row locks for InnoDB tables, in milliseconds.
The average time to acquire a row lock for InnoDB tables, in milliseconds.
The maximum time to acquire a row lock for InnoDB tables, in milliseconds.
The number of times operations on InnoDB tables had to wait for a row lock.
The number of rows deleted from InnoDB tables.
The number of rows inserted into InnoDB tables.
The number of rows read from InnoDB tables.
The number of rows updated in InnoDB tables.
The number of rows deleted from InnoDB tables belonging to system-created schemas.
The number of rows inserted into InnoDB tables belonging to system-created schemas.
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 15.6.3.4, “Undo Tablespaces”.
Innodb_undo_tablespaces_explicit
The number of user-created undo tablespaces. For information about undo tablespaces, see Section 15.6.3.4, “Undo Tablespaces”.
Innodb_undo_tablespaces_implicit
The number of undo tablespaces created by InnoDB. Two default undo tablespaces are created by InnoDB when the MySQL instance is initialized. For information about undo tablespaces, see Section 15.6.3.4, “Undo Tablespaces”.
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, see Section 15.6.3.4, “Undo Tablespaces”.
The number of key blocks in the MyISAM key cache that have changed but have not yet been flushed to disk.
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 of key_buffer_size in Section 5.1.8, “Server System Variables”.
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.
The number of requests to read a key block from the MyISAM key cache.
The number of physical reads of a key block from disk into the MyISAM key cache. If Key_reads is large, then your key_buffer_size value is probably too small. The cache miss rate can be calculated as Key_reads/Key_read_requests.
The number of requests to write a key block to the MyISAM key cache.
The number of physical writes of a key block from the MyISAM key cache to disk.
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.
In MySQL 8.0.16 and later, 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. (Bug #92766, Bug #28786951) Prior to MySQL 8.0.16, Last_query_cost was computed accurately only for simple, “flat” queries, but not for complex queries such as those containing subqueries or UNION. (For the latter, the value was set to 0.)
The number of iterations the query optimizer made in execution plan construction for the previous query. Last_query_cost has session scope.
The number of attempts to connect to locked user accounts. For information about account locking and unlocking, see Section 6.2.19, “Account Locking”.
The number of SELECT statements for which the execution timeout was exceeded.
The number of SELECT statements for which a nonzero execution timeout was set. This includes statements that include a nonzero MAX_EXECUTION_TIME optimizer hint, and statements that include no such hint but execute while the timeout indicated by the max_execution_time system variable is nonzero.
The number of SELECT statements for which the attempt to set an execution timeout failed.
The maximum number of connections that have been in use simultaneously since the server started.
The time at which Max_used_connections reached its current value.
This status variable is deprecated (because DELAYED inserts are not supported); expect it to be removed in a future release.
The character set currently used by the MeCab full-text parser plugin. For related information, see Section 12.10.9, “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 use gtid_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 use gtid_next=AUTOMATIC and that violate GTID consistency.
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.
The number of streams that are open (used mainly for logging).
The number of cached table definitions.
The number of tables that are open.
The number of files that have been opened with my_open() (a mysys library function). Parts of the server that open files without using this function do not increment the count.
The number of table definitions that have been cached.
The number of tables that have been opened. If Opened_tables is big, your table_open_cache value is probably too small.
Performance_schema_xxx
Performance Schema status variables are listed in Section 27.16, “Performance Schema Status Variables”. These variables provide information about instrumentation that could not be loaded or created due to memory constraints.
The current number of prepared statements. (The maximum number of statements is given by the max_prepared_stmt_count system variable.)
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 or COM_STATISTICS commands.
The discussion at the beginning of this section indicates how to relate this statement-counting status variable to other such variables.
The number of statements executed by the server. This includes only statements sent to the server by clients and not statements executed within stored programs, unlike the Queries variable. This variable does not count COM_PING, COM_STATISTICS, COM_STMT_PREPARE, COM_STMT_CLOSE, or COM_STMT_RESET commands.
The discussion at the beginning of this section indicates how to relate this statement-counting status variable to other such variables.
The number of semisynchronous replicas.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_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.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_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.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_net_waits
The total number of times the source waited for replica replies.
This variable is available only if the source-side semisynchronous replication plugin is installed.
The number of times the source turned off semisynchronous replication.
This variable is available only if the source-side semisynchronous replication plugin is installed.
The number of commits that were not acknowledged successfully by a replica.
This variable is available only if the source-side semisynchronous replication plugin is installed.
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.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_timefunc_failures
The number of times the source failed when calling time functions such as gettimeofday().
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_tx_avg_wait_time
The average time in microseconds the source waited for each transaction.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_tx_wait_time
The total time in microseconds the source waited for transactions.
This variable is available only if the source-side semisynchronous replication plugin is installed.
The total number of times the source waited for transactions.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_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.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_wait_sessions
The number of sessions currently waiting for replica replies.
This variable is available only if the source-side semisynchronous replication plugin is installed.
The number of commits that were acknowledged successfully by a replica.
This variable is available only if the source-side semisynchronous replication plugin is installed.
Whether semisynchronous replication currently is operational on the replica. This is ON if the plugin has been enabled and the replication I/O thread is running, OFF otherwise.
This variable is available only if the replica-side semisynchronous replication plugin is installed.
The value of this variable is the public key used by the sha256_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 the sha256_password_private_key_path and sha256_password_public_key_path system variables. The value of Rsa_public_key comes from the latter file.
For information about sha256_password, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”.
Secondary_engine_execution_count
The number of queries offloaded to a secondary engine. This variable was added in MySQL 8.0.13.
For use with HeatWave. See HeatWave User Guide.
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.
The number of joins that used a range search on a reference table.
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.
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.
The number of joins that did a full scan of the first table.
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; see Section 17.5.1.31, “Replication and Temporary Tables”. This variable reports the total count of open temporary tables for all replication channels.
Slave_rows_last_search_algorithm_used
The search algorithm that was most recently used by this replica to locate rows for row-based replication. The result shows whether the replica used indexes, a table scan, or hashing as the search algorithm for the last transaction executed on any channel.
The method used depends on the setting for the slave_rows_search_algorithms system variable, and the keys that are available on the relevant table.
This variable is available only for debug builds of MySQL.
The number of threads that have taken more than slow_launch_time seconds to create.
The number of queries that have taken more than long_query_time seconds. This counter increments regardless of whether the slow query log is enabled. For information about that log, see Section 5.4.5, “The Slow Query Log”.
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.
The number of sorts that were done using ranges.
The number of sorted rows.
The number of sorts that were done by scanning the table.
The number of negotiates needed to establish the connection.
The number of accepted SSL connections.
The number of callback cache hits.
The current encryption cipher (empty for unencrypted connections).
The list of possible SSL ciphers (empty for non-SSL connections). If MySQL supports TLSv1.3, the value includes the possible TLSv1.3 ciphersuites. See Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
The number of SSL connection attempts to an SSL-enabled replication source server.
The number of negotiates needed to establish the connection to an SSL-enabled replication source server.
The SSL context verification depth (how many certificates in the chain are tested).
The SSL context verification mode.
The default SSL timeout.
The number of successful SSL connections to the server.
The number of successful replica connections to an SSL-enabled replication source server.
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 |
+-----------------------+--------------------------+The first date for which the SSL certificate is valid.
The number of SSL session cache hits.
The number of SSL session cache misses.
The SSL session cache mode.
The number of SSL session cache overflows.
The SSL session cache size.
The number of SSL session cache timeouts.
How many SSL connections were reused from the cache.
Ssl_used_session_cache_entries
How many SSL session cache entries were used.
The verification depth for replication SSL connections.
The verification mode used by the server for a connection that uses SSL. The value is a bitmask; bits are defined in the openssl/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.
The SSL protocol version of the connection (for example, TLSv1). If the connection is not encrypted, the value is empty.
The number of times that a request for a table lock could be granted immediately.
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.
The number of hits for open tables cache lookups.
The number of misses for open tables cache lookups.
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.
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 of Tc_log_max_pages_used and Tc_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.)
The page size used for the memory-mapped implementation of the XA recovery log. The default value is determined using getpagesize(). This variable is unused for the same reasons as described for Tc_log_max_pages_used.
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.)
The number of threads in the thread cache.
The number of currently open connections.
The number of threads created to handle connections. If Threads_created is big, you may want to increase the thread_cache_size value. The cache miss rate can be calculated as Threads_created/Connections.
The number of threads that are not sleeping.
The number of seconds that the server has been up.
The number of seconds since the most recent FLUSH STATUS statement.