5.1.6 Server Status Variables
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5.1.6 Server Status Variables
The 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 13.7.5.34, “SHOW STATUS
Syntax”). 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.
The following table lists all available server status variables:
Table 5.4 Status Variable Summary
Aborted_clients
numericGLOBAL
Aborted_connects
numericGLOBAL
Binlog_cache_disk_use
numericGLOBAL
Binlog_cache_use
numericGLOBAL
Binlog_stmt_cache_disk_use
numericGLOBAL
Binlog_stmt_cache_use
numericGLOBAL
Bytes_received
numericGLOBAL
| SESSION
Bytes_sent
numericGLOBAL
| SESSION
Com_admin_commands
numericGLOBAL
| SESSION
Com_alter_db
numericGLOBAL
| SESSION
Com_alter_db_upgrade
numericGLOBAL
| SESSION
Com_alter_event
numericGLOBAL
| SESSION
Com_alter_function
numericGLOBAL
| SESSION
Com_alter_procedure
numericGLOBAL
| SESSION
Com_alter_server
numericGLOBAL
| SESSION
Com_alter_table
numericGLOBAL
| SESSION
Com_alter_tablespace
numericGLOBAL
| SESSION
Com_alter_user
numericGLOBAL
| SESSION
Com_analyze
numericGLOBAL
| SESSION
Com_assign_to_keycache
numericGLOBAL
| SESSION
Com_begin
numericGLOBAL
| SESSION
Com_binlog
numericGLOBAL
| SESSION
Com_call_procedure
numericGLOBAL
| SESSION
Com_change_db
numericGLOBAL
| SESSION
Com_change_master
numericGLOBAL
| SESSION
Com_change_repl_filter
numericGLOBAL
| SESSION
Com_check
numericGLOBAL
| SESSION
Com_checksum
numericGLOBAL
| SESSION
Com_commit
numericGLOBAL
| SESSION
Com_create_db
numericGLOBAL
| SESSION
Com_create_event
numericGLOBAL
| SESSION
Com_create_function
numericGLOBAL
| SESSION
Com_create_index
numericGLOBAL
| SESSION
Com_create_procedure
numericGLOBAL
| SESSION
Com_create_server
numericGLOBAL
| SESSION
Com_create_table
numericGLOBAL
| SESSION
Com_create_trigger
numericGLOBAL
| SESSION
Com_create_udf
numericGLOBAL
| SESSION
Com_create_user
numericGLOBAL
| SESSION
Com_create_view
numericGLOBAL
| SESSION
Com_dealloc_sql
numericGLOBAL
| SESSION
Com_delete
numericGLOBAL
| SESSION
Com_delete_multi
numericGLOBAL
| SESSION
Com_do
numericGLOBAL
| SESSION
Com_drop_db
numericGLOBAL
| SESSION
Com_drop_event
numericGLOBAL
| SESSION
Com_drop_function
numericGLOBAL
| SESSION
Com_drop_index
numericGLOBAL
| SESSION
Com_drop_procedure
numericGLOBAL
| SESSION
Com_drop_server
numericGLOBAL
| SESSION
Com_drop_table
numericGLOBAL
| SESSION
Com_drop_trigger
numericGLOBAL
| SESSION
Com_drop_user
numericGLOBAL
| SESSION
Com_drop_view
numericGLOBAL
| SESSION
Com_empty_query
numericGLOBAL
| SESSION
Com_execute_sql
numericGLOBAL
| SESSION
Com_flush
numericGLOBAL
| SESSION
Com_get_diagnostics
numericGLOBAL
| SESSION
Com_grant
numericGLOBAL
| SESSION
Com_ha_close
numericGLOBAL
| SESSION
Com_ha_open
numericGLOBAL
| SESSION
Com_ha_read
numericGLOBAL
| SESSION
Com_help
numericGLOBAL
| SESSION
Com_insert
numericGLOBAL
| SESSION
Com_insert_select
numericGLOBAL
| SESSION
Com_install_plugin
numericGLOBAL
| SESSION
Com_kill
numericGLOBAL
| SESSION
Com_load
numericGLOBAL
| SESSION
Com_lock_tables
numericGLOBAL
| SESSION
Com_optimize
numericGLOBAL
| SESSION
Com_preload_keys
numericGLOBAL
| SESSION
Com_prepare_sql
numericGLOBAL
| SESSION
Com_purge
numericGLOBAL
| SESSION
Com_purge_before_date
numericGLOBAL
| SESSION
Com_release_savepoint
numericGLOBAL
| SESSION
Com_rename_table
numericGLOBAL
| SESSION
Com_rename_user
numericGLOBAL
| SESSION
Com_repair
numericGLOBAL
| SESSION
Com_replace
numericGLOBAL
| SESSION
Com_replace_select
numericGLOBAL
| SESSION
Com_reset
numericGLOBAL
| SESSION
Com_resignal
numericGLOBAL
| SESSION
Com_revoke
numericGLOBAL
| SESSION
Com_revoke_all
numericGLOBAL
| SESSION
Com_rollback
numericGLOBAL
| SESSION
Com_rollback_to_savepoint
numericGLOBAL
| SESSION
Com_savepoint
numericGLOBAL
| SESSION
Com_select
numericGLOBAL
| SESSION
Com_set_option
numericGLOBAL
| SESSION
Com_show_authors
numericGLOBAL
| SESSION
Com_show_binlog_events
numericGLOBAL
| SESSION
Com_show_binlogs
numericGLOBAL
| SESSION
Com_show_charsets
numericGLOBAL
| SESSION
Com_show_collations
numericGLOBAL
| SESSION
Com_show_contributors
numericGLOBAL
| SESSION
Com_show_create_db
numericGLOBAL
| SESSION
Com_show_create_event
numericGLOBAL
| SESSION
Com_show_create_func
numericGLOBAL
| SESSION
Com_show_create_proc
numericGLOBAL
| SESSION
Com_show_create_table
numericGLOBAL
| SESSION
Com_show_create_trigger
numericGLOBAL
| SESSION
Com_show_databases
numericGLOBAL
| SESSION
Com_show_engine_logs
numericGLOBAL
| SESSION
Com_show_engine_mutex
numericGLOBAL
| SESSION
Com_show_engine_status
numericGLOBAL
| SESSION
Com_show_errors
numericGLOBAL
| SESSION
Com_show_events
numericGLOBAL
| SESSION
Com_show_fields
numericGLOBAL
| SESSION
Com_show_function_code
numericGLOBAL
| SESSION
Com_show_function_status
numericGLOBAL
| SESSION
Com_show_grants
numericGLOBAL
| SESSION
Com_show_keys
numericGLOBAL
| SESSION
Com_show_master_status
numericGLOBAL
| SESSION
Com_show_new_master
numericGLOBAL
| SESSION
Com_show_open_tables
numericGLOBAL
| SESSION
Com_show_plugins
numericGLOBAL
| SESSION
Com_show_privileges
numericGLOBAL
| SESSION
Com_show_procedure_code
numericGLOBAL
| SESSION
Com_show_procedure_status
numericGLOBAL
| SESSION
Com_show_processlist
numericGLOBAL
| SESSION
Com_show_profile
numericGLOBAL
| SESSION
Com_show_profiles
numericGLOBAL
| SESSION
Com_show_relaylog_events
numericGLOBAL
| SESSION
Com_show_slave_hosts
numericGLOBAL
| SESSION
Com_show_slave_status
numericGLOBAL
| SESSION
Com_show_status
numericGLOBAL
| SESSION
Com_show_storage_engines
numericGLOBAL
| SESSION
Com_show_table_status
numericGLOBAL
| SESSION
Com_show_tables
numericGLOBAL
| SESSION
Com_show_triggers
numericGLOBAL
| SESSION
Com_show_variables
numericGLOBAL
| SESSION
Com_show_warnings
numericGLOBAL
| SESSION
Com_signal
numericGLOBAL
| SESSION
Com_slave_start
numericGLOBAL
| SESSION
Com_slave_stop
numericGLOBAL
| SESSION
Com_stmt_close
numericGLOBAL
| SESSION
Com_stmt_execute
numericGLOBAL
| SESSION
Com_stmt_fetch
numericGLOBAL
| SESSION
Com_stmt_prepare
numericGLOBAL
| SESSION
Com_stmt_reprepare
numericGLOBAL
| SESSION
Com_stmt_reset
numericGLOBAL
| SESSION
Com_stmt_send_long_data
numericGLOBAL
| SESSION
Com_truncate
numericGLOBAL
| SESSION
Com_uninstall_plugin
numericGLOBAL
| SESSION
Com_unlock_tables
numericGLOBAL
| SESSION
Com_update
numericGLOBAL
| SESSION
Com_update_multi
numericGLOBAL
| SESSION
Com_xa_commit
numericGLOBAL
| SESSION
Com_xa_end
numericGLOBAL
| SESSION
Com_xa_prepare
numericGLOBAL
| SESSION
Com_xa_recover
numericGLOBAL
| SESSION
Com_xa_rollback
numericGLOBAL
| SESSION
Com_xa_start
numericGLOBAL
| SESSION
Compression
numericSESSION
Connection_errors_accept
numericGLOBAL
Connection_errors_internal
numericGLOBAL
Connection_errors_max_connections
numericGLOBAL
Connection_errors_peer_addr
numericGLOBAL
Connection_errors_select
numericGLOBAL
Connection_errors_tcpwrap
numericGLOBAL
Connections
numericGLOBAL
Created_tmp_disk_tables
numericGLOBAL
| SESSION
Created_tmp_files
numericGLOBAL
Created_tmp_tables
numericGLOBAL
| SESSION
Delayed_errors
numericGLOBAL
Delayed_insert_threads
numericGLOBAL
Delayed_writes
numericGLOBAL
Flush_commands
numericGLOBAL
Handler_commit
numericGLOBAL
| SESSION
Handler_delete
numericGLOBAL
| SESSION
Handler_discover
numericGLOBAL
| SESSION
Handler_external_lock
numericGLOBAL
| SESSION
Handler_mrr_init
numericGLOBAL
| SESSION
Handler_prepare
numericGLOBAL
| SESSION
Handler_read_first
numericGLOBAL
| SESSION
Handler_read_key
numericGLOBAL
| SESSION
Handler_read_last
numericGLOBAL
| SESSION
Handler_read_next
numericGLOBAL
| SESSION
Handler_read_prev
numericGLOBAL
| SESSION
Handler_read_rnd
numericGLOBAL
| SESSION
Handler_read_rnd_next
numericGLOBAL
| SESSION
Handler_rollback
numericGLOBAL
| SESSION
Handler_savepoint
numericGLOBAL
| SESSION
Handler_savepoint_rollback
numericGLOBAL
| SESSION
Handler_update
numericGLOBAL
| SESSION
Handler_write
numericGLOBAL
| SESSION
Innodb_available_undo_logs
numericGLOBAL
Innodb_buffer_pool_bytes_data
numericGLOBAL
Innodb_buffer_pool_bytes_dirty
numericGLOBAL
Innodb_buffer_pool_dump_status
numericGLOBAL
Innodb_buffer_pool_load_status
numericGLOBAL
Innodb_buffer_pool_pages_data
numericGLOBAL
Innodb_buffer_pool_pages_dirty
numericGLOBAL
Innodb_buffer_pool_pages_flushed
numericGLOBAL
Innodb_buffer_pool_pages_free
numericGLOBAL
Innodb_buffer_pool_pages_latched
numericGLOBAL
Innodb_buffer_pool_pages_misc
numericGLOBAL
Innodb_buffer_pool_pages_total
numericGLOBAL
Innodb_buffer_pool_read_ahead
numericGLOBAL
Innodb_buffer_pool_read_ahead_evicted
numericGLOBAL
Innodb_buffer_pool_read_requests
numericGLOBAL
Innodb_buffer_pool_reads
numericGLOBAL
Innodb_buffer_pool_wait_free
numericGLOBAL
Innodb_buffer_pool_write_requests
numericGLOBAL
Innodb_data_fsyncs
numericGLOBAL
Innodb_data_pending_fsyncs
numericGLOBAL
Innodb_data_pending_reads
numericGLOBAL
Innodb_data_pending_writes
numericGLOBAL
Innodb_data_read
numericGLOBAL
Innodb_data_reads
numericGLOBAL
Innodb_data_writes
numericGLOBAL
Innodb_data_written
numericGLOBAL
Innodb_dblwr_pages_written
numericGLOBAL
Innodb_dblwr_writes
numericGLOBAL
Innodb_have_atomic_builtins
numericGLOBAL
Innodb_log_waits
numericGLOBAL
Innodb_log_write_requests
numericGLOBAL
Innodb_log_writes
numericGLOBAL
Innodb_num_open_files
numericGLOBAL
Innodb_os_log_fsyncs
numericGLOBAL
Innodb_os_log_pending_fsyncs
numericGLOBAL
Innodb_os_log_pending_writes
numericGLOBAL
Innodb_os_log_written
numericGLOBAL
Innodb_page_size
numericGLOBAL
Innodb_pages_created
numericGLOBAL
Innodb_pages_read
numericGLOBAL
Innodb_pages_written
numericGLOBAL
Innodb_row_lock_current_waits
numericGLOBAL
Innodb_row_lock_time
numericGLOBAL
Innodb_row_lock_time_avg
numericGLOBAL
Innodb_row_lock_time_max
numericGLOBAL
Innodb_row_lock_waits
numericGLOBAL
Innodb_rows_deleted
numericGLOBAL
Innodb_rows_inserted
numericGLOBAL
Innodb_rows_read
numericGLOBAL
Innodb_rows_updated
numericGLOBAL
Innodb_truncated_status_writes
numericGLOBAL
Key_blocks_not_flushed
numericGLOBAL
Key_blocks_unused
numericGLOBAL
Key_blocks_used
numericGLOBAL
Key_read_requests
numericGLOBAL
Key_reads
numericGLOBAL
Key_write_requests
numericGLOBAL
Key_writes
numericGLOBAL
Last_query_cost
numericSESSION
Last_query_partial_plans
numericSESSION
Max_statement_time_exceeded
numericGLOBAL
| SESSION
Max_statement_time_set
numericGLOBAL
| SESSION
Max_statement_time_set_failed
numericGLOBAL
| SESSION
Max_used_connections
numericGLOBAL
Max_used_connections_time
datetimeGLOBAL
Ndb_conflict_fn_max
numericGLOBAL
Ndb_conflict_fn_old
numericGLOBAL
Ndb_number_of_data_nodes
numericGLOBAL
Not_flushed_delayed_rows
numericGLOBAL
Open_files
numericGLOBAL
Open_streams
numericGLOBAL
Open_table_definitions
numericGLOBAL
Open_tables
numericGLOBAL
| SESSION
Opened_files
numericGLOBAL
Opened_table_definitions
numericGLOBAL
| SESSION
Opened_tables
numericGLOBAL
| SESSION
Performance_schema_accounts_lost
numericGLOBAL
Performance_schema_cond_classes_lost
numericGLOBAL
Performance_schema_cond_instances_lost
numericGLOBAL
Performance_schema_digest_lost
numericGLOBAL
Performance_schema_file_classes_lost
numericGLOBAL
Performance_schema_file_handles_lost
numericGLOBAL
Performance_schema_file_instances_lost
numericGLOBAL
Performance_schema_hosts_lost
numericGLOBAL
Performance_schema_locker_lost
numericGLOBAL
Performance_schema_memory_classes_lost
numericGLOBAL
Performance_schema_metadata_lock_lost
numericGLOBAL
Performance_schema_mutex_classes_lost
numericGLOBAL
Performance_schema_mutex_instances_lost
numericGLOBAL
Performance_schema_nested_statement_lost
numericGLOBAL
Performance_schema_prepared_statements_lost
numericGLOBAL
Performance_schema_program_lost
numericGLOBAL
Performance_schema_rwlock_classes_lost
numericGLOBAL
Performance_schema_rwlock_instances_lost
numericGLOBAL
Performance_schema_session_connect_attrs_lost
numericGLOBAL
Performance_schema_socket_classes_lost
numericGLOBAL
Performance_schema_socket_instances_lost
numericGLOBAL
Performance_schema_stage_classes_lost
numericGLOBAL
Performance_schema_statement_classes_lost
numericGLOBAL
Performance_schema_table_handles_lost
numericGLOBAL
Performance_schema_table_instances_lost
numericGLOBAL
Performance_schema_thread_classes_lost
numericGLOBAL
Performance_schema_thread_instances_lost
numericGLOBAL
Performance_schema_users_lost
numericGLOBAL
Prepared_stmt_count
numericGLOBAL
Qcache_free_blocks
numericGLOBAL
Qcache_free_memory
numericGLOBAL
Qcache_hits
numericGLOBAL
Qcache_inserts
numericGLOBAL
Qcache_lowmem_prunes
numericGLOBAL
Qcache_not_cached
numericGLOBAL
Qcache_queries_in_cache
numericGLOBAL
Qcache_total_blocks
numericGLOBAL
Queries
numericGLOBAL
| SESSION
Questions
numericGLOBAL
| SESSION
Rpl_semi_sync_master_clients
numericGLOBAL
Rpl_semi_sync_master_net_avg_wait_time
numericGLOBAL
Rpl_semi_sync_master_net_wait_time
numericGLOBAL
Rpl_semi_sync_master_net_waits
numericGLOBAL
Rpl_semi_sync_master_no_times
numericGLOBAL
Rpl_semi_sync_master_no_tx
numericGLOBAL
Rpl_semi_sync_master_status
booleanGLOBAL
Rpl_semi_sync_master_timefunc_failures
numericGLOBAL
Rpl_semi_sync_master_tx_avg_wait_time
numericGLOBAL
Rpl_semi_sync_master_tx_wait_time
numericGLOBAL
Rpl_semi_sync_master_tx_waits
numericGLOBAL
Rpl_semi_sync_master_wait_pos_backtraverse
numericGLOBAL
Rpl_semi_sync_master_wait_sessions
numericGLOBAL
Rpl_semi_sync_master_yes_tx
numericGLOBAL
Rpl_semi_sync_slave_status
booleanGLOBAL
Rsa_public_key
stringGLOBAL
Select_full_join
numericGLOBAL
| SESSION
Select_full_range_join
numericGLOBAL
| SESSION
Select_range
numericGLOBAL
| SESSION
Select_range_check
numericGLOBAL
| SESSION
Select_scan
numericGLOBAL
| SESSION
Slave_heartbeat_period
GLOBAL
Slave_last_heartbeat
GLOBAL
Slave_open_temp_tables
numericGLOBAL
Slave_received_heartbeats
GLOBAL
Slave_retried_transactions
numericGLOBAL
Slave_running
booleanGLOBAL
Slow_launch_threads
numericGLOBAL
| SESSION
Slow_queries
numericGLOBAL
| SESSION
Sort_merge_passes
numericGLOBAL
| SESSION
Sort_range
numericGLOBAL
| SESSION
Sort_rows
numericGLOBAL
| SESSION
Sort_scan
numericGLOBAL
| SESSION
Ssl_accept_renegotiates
numericGLOBAL
Ssl_accepts
numericGLOBAL
Ssl_callback_cache_hits
numericGLOBAL
Ssl_cipher
stringGLOBAL
| SESSION
Ssl_cipher_list
stringGLOBAL
| SESSION
Ssl_client_connects
numericGLOBAL
Ssl_connect_renegotiates
numericGLOBAL
Ssl_ctx_verify_depth
numericGLOBAL
Ssl_ctx_verify_mode
numericGLOBAL
Ssl_default_timeout
numericGLOBAL
| SESSION
Ssl_finished_accepts
numericGLOBAL
Ssl_finished_connects
numericGLOBAL
Ssl_server_not_after
numericGLOBAL
| SESSION
Ssl_server_not_before
numericGLOBAL
| SESSION
Ssl_session_cache_hits
numericGLOBAL
Ssl_session_cache_misses
numericGLOBAL
Ssl_session_cache_mode
stringGLOBAL
Ssl_session_cache_overflows
numericGLOBAL
Ssl_session_cache_size
numericGLOBAL
Ssl_session_cache_timeouts
numericGLOBAL
Ssl_sessions_reused
numericGLOBAL
| SESSION
Ssl_used_session_cache_entries
numericGLOBAL
Ssl_verify_depth
numericGLOBAL
| SESSION
Ssl_verify_mode
numericGLOBAL
| SESSION
Ssl_version
stringGLOBAL
| SESSION
Table_locks_immediate
numericGLOBAL
Table_locks_waited
numericGLOBAL
Table_open_cache_hits
numericGLOBAL
| SESSION
Table_open_cache_misses
numericGLOBAL
| SESSION
Table_open_cache_overflows
numericGLOBAL
| SESSION
Tc_log_max_pages_used
numericGLOBAL
Tc_log_page_size
numericGLOBAL
Tc_log_page_waits
numericGLOBAL
Threads_cached
numericGLOBAL
Threads_connected
numericGLOBAL
Threads_created
numericGLOBAL
Threads_running
numericGLOBAL
Uptime
numericGLOBAL
Uptime_since_flush_status
numericGLOBAL
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 C.5.2.11, “Communication Errors and Aborted Connections”.
Aborted_connects
The number of failed attempts to connect to the MySQL server. See Section C.5.2.11, “Communication Errors and Aborted Connections”.
For additional connection-related information, check the
Connection_errors_
status variables and thexxx
host_cache
table.As of MySQL 5.7.3,
Aborted_connects
is not visible in the embedded server because for that server it is not updated and is not meaningful.Binlog_cache_disk_use
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.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 of
binlog_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.
Com_
xxx
The
Com_
statement counter variables indicate the number of times eachxxx
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.If a query result is returned from query cache, the server increments the
Qcache_hits
status variable, notCom_select
. See Section 8.9.3.4, “Query Cache Status and Maintenance”.All of the
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.xxx
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 asmysql_stmt_prepare(), mysql_stmt_execute(), and so forth are executed. However,xxx
Com_stmt_prepare
,Com_stmt_execute
andCom_stmt_close
also increase forPREPARE
,EXECUTE
, orDEALLOCATE PREPARE
, respectively. Additionally, the values of the older statement counter variablesCom_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 after metadata changes to tables or views referred to by the statement. A reprepare operation incrementsCom_stmt_reprepare
, and alsoCom_stmt_prepare
.Com_change_repl_filter
indicates the number ofCHANGE REPLICATION FILTER
statements executed. It was introduced in MySQL 5.7.3.Compression
Whether the client connection uses compression in the client/server protocol.
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 8.11.5.2, “DNS Lookup Optimization 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).
As of MySQL 5.7.3, the
Connection_errors_
status variables are not visible in the embedded server because for that server they are not updated and are not meaningful.xxx
Connection_errors_accept
The number of errors that occurred during calls to
accept()
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 server
max_connections
limit was reached.Connection_errors_peer_addr
The number of errors that occurred while searching for connecting client IP addresses.
Connection_errors_select
The number of errors that occurred during calls to
select()
orpoll()
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 the
libwrap
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.
If an internal temporary table is created initially as an in-memory table but becomes too large, MySQL automatically converts it to an on-disk table. The maximum size for in-memory temporary tables is the minimum of the
tmp_table_size
andmax_heap_table_size
values. IfCreated_tmp_disk_tables
is large, you may want to increase thetmp_table_size
ormax_heap_table_size
value to lessen the likelihood that internal temporary tables in memory will be converted to on-disk tables.You can compare the number of internal on-disk temporary tables created to the total number of internal temporary tables created by comparing the values of the
Created_tmp_disk_tables
andCreated_tmp_tables
variables.See also Section 8.4.4, “How MySQL Uses Internal Temporary Tables”.
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 comparing the values of the
Created_tmp_disk_tables
andCreated_tmp_tables
variables.See also Section 8.4.4, “How MySQL Uses Internal Temporary Tables”.
Each invocation of the
SHOW STATUS
statement uses an internal temporary table and increments the globalCreated_tmp_tables
value.Delayed_errors
In MySQL 5.7, this status variable is deprecated (because
DELAYED
inserts are not supported), and will be removed in a future release.Delayed_insert_threads
In MySQL 5.7, this status variable is deprecated (because
DELAYED
inserts are not supported), and will be removed in a future release.Delayed_writes
In MySQL 5.7, this status variable is deprecated (because
DELAYED
inserts are not supported), and will be removed in a future release.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 aCOM_REFRESH
packet. This is in contrast toCom_flush
, which indicates how manyFLUSH
statements have been executed, whetherFLUSH TABLES
,FLUSH LOGS
, and so forth.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 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.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 thatcol1
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. With
ORDER BY
, the server will issue a first-key request followed by several next-key requests, whereas with WithORDER BY DESC
, the server will issue 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_available_undo_logs
The total number of available
InnoDB
undo logs. Supplements theinnodb_undo_logs
system variable, which reports the number of active undo logs.Innodb_buffer_pool_dump_status
The progress of an operation to record the pages held in the
InnoDB
buffer pool, triggered by the setting ofinnodb_buffer_pool_dump_at_shutdown
orinnodb_buffer_pool_dump_now
.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 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
.Innodb_buffer_pool_bytes_data
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 withInnodb_buffer_pool_pages_data
, whencompressed tables cause the buffer pool to hold pages of different sizes.Innodb_buffer_pool_pages_data
The number of pages in the
InnoDB
buffer pool containing data. The number includes both dirty and clean pages.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 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 to flush pages from the
InnoDB
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 be flushed or removed for some other reason. Calculation of this variable is expensive, so it is available only when theUNIV_DEBUG
system is defined at server build time.Innodb_buffer_pool_pages_misc
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 asInnodb_buffer_pool_pages_total
–Innodb_buffer_pool_pages_free
–Innodb_buffer_pool_pages_data
.Innodb_buffer_pool_pages_total
The total size of the
InnoDB
buffer pool, in pages.Innodb_buffer_pool_read_ahead
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_requests
The number of logical read requests.
Innodb_buffer_pool_reads
The number of logical reads that
InnoDB
could not satisfy from the buffer pool, and had to read directly from disk.Innodb_buffer_pool_wait_free
Normally, writes to the
InnoDB
buffer pool happen in the background. WhenInnoDB
needs to read or create apage 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. 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 offsync()
calls is influenced by the setting of theinnodb_flush_method
configuration option.Innodb_data_pending_fsyncs
The current number of pending
fsync()
operations. The frequency offsync()
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.
Innodb_data_reads
The total number of data 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 the doublewrite buffer. See Section 14.2.10.1, “
InnoDB
Disk I/O”.Innodb_dblwr_writes
The number of doublewrite operations that have been performed. See Section 14.2.10.1, “
InnoDB
Disk I/O”.Innodb_have_atomic_builtins
Indicates whether the server was built with atomic instructions.
Innodb_log_waits
The number of times that the log 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 theInnoDB
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
The compiled-in
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 on
InnoDB
tables.Innodb_pages_read
The number of pages read by operations on
InnoDB
tables.Innodb_pages_written
The number of pages written by operations on
InnoDB
tables.Innodb_row_lock_current_waits
The number of row locks currently being waited for by operations on
InnoDB
tables.Innodb_row_lock_time
The total time spent in acquiring row locks for
InnoDB
tables, in milliseconds.Innodb_row_lock_time_avg
The average time to acquire a row lock for
InnoDB
tables, in milliseconds.Innodb_row_lock_time_max
The maximum time to acquire a row lock for
InnoDB
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 number of rows updated in
InnoDB
tables.Innodb_truncated_status_writes
The number of times output from the
SHOW ENGINE INNODB STATUS
statement has been truncated.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
in Section 5.1.4, “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 the
MyISAM
key cache.Key_reads
The number of physical reads of a key block from disk into the
MyISAM
key cache. IfKey_reads
is large, then yourkey_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 the
MyISAM
key cache.Key_writes
The number of physical writes of a key block from the
MyISAM
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.The
Last_query_cost
value can be computed accurately only for simple “flat” queries, not complex queries such as those with subqueries orUNION
. For the latter, the value is set to 0.Last_query_partial_plans
The number of iterations the query optimizer made in execution plan construction for the previous query.
Last_query_cost
has session scope.Max_statement_time_exceeded
The number of
SELECT
statements for which the execution timeout was exceeded. This variable was added in MySQL 5.7.4.Max_statement_time_set
The number of
SELECT
statements for which a nonzero execution timeout was set. This includes statements that include a nonzeroMAX_STATEMENT_TIME
option, and statements that include no such option but execute while the timeout indicated by themax_statement_time
system variable is nonzero. This variable was added in MySQL 5.7.4.Max_statement_time_set_failed
The number of
SELECT
statements for which the attempt to set an execution timeout failed. This variable was added in MySQL 5.7.4.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 which
Max_used_connections
reached its current value. This variable was added in MySQL 5.7.5.Not_flushed_delayed_rows
In MySQL 5.7, this status variable is deprecated (because
DELAYED
inserts are not supported), and will be removed in a future release.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
.frm
files.Open_tables
The number of tables that are open.
Opened_files
The number of files that have been opened with
my_open()
(amysys
library function). Parts of the server that open files without using this function do not increment the count.Opened_table_definitions
The number of
.frm
files that have been cached.Opened_tables
The number of tables that have been opened. If
Opened_tables
is big, yourtable_open_cache
value is probably too small.Performance_schema_
xxx
Performance Schema status variables are listed in Section 20.13, “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 the
max_prepared_stmt_count
system variable.)Qcache_free_blocks
The number of free memory blocks in the query cache.
Qcache_free_memory
The amount of free memory for the query cache.
Qcache_hits
The number of query cache hits.
Qcache_inserts
The number of queries added to the query cache.
Qcache_lowmem_prunes
The number of queries that were deleted from the query cache because of low memory.
Qcache_not_cached
The number of noncached queries (not cacheable, or not cached due to the
query_cache_type
setting).Qcache_queries_in_cache
The number of queries registered in the query cache.
Qcache_total_blocks
The total number of blocks in the query cache.
Queries
The number of statements executed by the server. This variable includes statements executed within stored programs, unlike the
Questions
variable. It does not countCOM_PING
orCOM_STATISTICS
commands.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 the
Queries
variable. This variable does not countCOM_PING
,COM_STATISTICS
,COM_STMT_PREPARE
,COM_STMT_CLOSE
, orCOM_STMT_RESET
commands.Rpl_semi_sync_master_clients
The number of semisynchronous slaves.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_net_avg_wait_time
The average time in microseconds the master waited for a slave reply.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_net_wait_time
The total time in microseconds the master waited for slave replies.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_net_waits
The total number of times the master waited for slave replies.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_no_times
The number of times the master turned off semisynchronous replication.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_no_tx
The number of commits that were not acknowledged successfully by a slave.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_status
Whether semisynchronous replication currently is operational on the master. The value is
ON
if the plugin has been enabled and a commit acknowledgment has occurred. It isOFF
if the plugin is not enabled or the master has fallen back to asynchronous replication due to commit acknowledgment timeout.This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_timefunc_failures
The number of times the master failed when calling time functions such as
gettimeofday()
.This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_tx_avg_wait_time
The average time in microseconds the master waited for each transaction.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_tx_wait_time
The total time in microseconds the master waited for transactions.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_tx_waits
The total number of times the master waited for transactions.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_wait_pos_backtraverse
The total number of times the master 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 master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_wait_sessions
The number of sessions currently waiting for slave replies.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_master_yes_tx
The number of commits that were acknowledged successfully by a slave.
This variable is available only if the master-side semisynchronous replication plugin is installed.
Rpl_semi_sync_slave_status
Whether semisynchronous replication currently is operational on the slave. This is
ON
if the plugin has been enabled and the slave I/O thread is running,OFF
otherwise.This variable is available only if the slave-side semisynchronous replication plugin is installed.
Rsa_public_key
The RSA public key value used by the
sha256_password
authentication plugin. 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
, see Section 6.3.9.4, “The SHA-256 Authentication Plugin”.This variable is available only if MySQL was built using OpenSSL.
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_heartbeat_period
Shows the replication heartbeat interval (in seconds) on a replication slave.
Slave_last_heartbeat
Shows when the most recent heartbeat signal was received by a replication slave, as a
TIMESTAMP
value.Slave_open_temp_tables
The number of temporary tables that the slave SQL thread currently has open. If the value is greater than zero, it is not safe to shut down the slave; see Section 16.4.1.22, “Replication and Temporary Tables”.
Slave_received_heartbeats
This counter increments with each replication heartbeat received by a replication slave since the last time that the slave was restarted or reset, or a
CHANGE MASTER TO
statement was issued.Slave_retried_transactions
The total number of times since startup that the replication slave SQL thread has retried transactions.
Slave_running
This is
ON
if this server is a replication slave that is connected to a replication master, and both the I/O and SQL threads are running; otherwise, it isOFF
.Slow_launch_threads
The number of threads that have taken more than
slow_launch_time
seconds to create.This variable is not meaningful in the embedded server (
libmysqld
) and as of MySQL 5.7.2 is no longer visible within the embedded server.Slow_queries
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 5.2.5, “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 SSL cipher (empty for non-SSL connections).
Ssl_cipher_list
The list of possible SSL ciphers.
Ssl_client_connects
The number of SSL connection attempts to an SSL-enabled master.
Ssl_connect_renegotiates
The number of negotiates needed to establish the connection to an SSL-enabled master.
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 slave connections to an SSL-enabled master.
Ssl_server_not_after
The last date for which the SSL certificate is valid.
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.
Ssl_session_cache_overflows
The number of SSL session cache overflows.
Ssl_session_cache_size
The SSL session cache size.
Ssl_session_cache_timeouts
The number of SSL session cache timeouts.
Ssl_sessions_reused
How many SSL connections were reused from the cache.
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 for replication SSL connections.
Ssl_version
The SSL protocol version of the connection.
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 of
Tc_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. Currently, 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 capable of two-phase commit 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 using
getpagesize()
. Currently, 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.)Threads_cached
The number of threads in the thread cache.
This variable is not meaningful in the embedded server (
libmysqld
) and as of MySQL 5.7.2 is no longer visible within the embedded server.Threads_connected
The number of currently open connections.
Threads_created
The number of threads created to handle connections. If
Threads_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.
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.
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User Comments
Posted by Demetrios Stavrinos on July 22 2004 12:27pm[Delete] [Edit]Reading the explanation for Handler read rnd next , I question it! I list some number from a test db that does almost all accesses by locating a record with a key (GE or xxx%) and then using next to access related record; yet the Handler read rnd next is relatively large.
Posted by Heikki Hannikainen on April 28 2006 10:23am[Delete] [Edit]Handler read key 42053
Handler read next 453703
Handler read rnd 696
Handler read rnd next 104378
On MySQL 5.0 the com_* variables of 'show status' are counted for the current connection only. The new undocumented command 'show global status' shows server-wide counters. (http://bugs.mysql.com/bug.php?id=19422)
Posted by sheila yao on April 16 2007 9:23pm[Delete] [Edit]In version 4.0.17, the explanation to Handler_ is different:
Posted by Roel Van de Paar on September 21 2009 4:34am[Delete] [Edit]Example:
Handler_delete:
The number of times a row was deleted from a table.
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.
Could this be a typo for Handler_delete? Because requests and rows updated/deleted/inserted are different concept.
Sheila
There's a bug in 5.0.36 (and likely surrounding versions) for Handler_write: it increases by one every time a row from SHOW STATUS is displayed:
1 row in set (0.00 sec)------
mysql> FLUSH STATUS;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW GLOBAL STATUS; SHOW SESSION STATUS;
[...] 224 rows in set (0.01 sec)
[...] 224 rows in set (0.01 sec)
mysql> SHOW SESSION STATUS LIKE 'Handler_write';
------
Given the bug for Handler_write it is not possible to find out how many rows were inserted in this version, unless you use a workaround:
Rows_inserted= Handler_write - (number of times SHOW STATUS was run * number of rows SHOW STATUS displayed)
This could be programmed further using the Com_show_status variable:
--------
mysql> SHOW SESSION STATUS LIKE 'Com_show_status';
1 row in set (0.00 sec)
--------
So, on a system/version that had 224 rows in SHOW STATUS (please check), the workaround formula would be:
Rows_inserted=Handler_write-(Com_show_status * 224)
Note though that this workaround does not work when using partial SHOW STATUS statements (using LIKE etc) from time to time.