# General Thread States
This article documents the major general thread states. More specific lists related to [delayed inserts](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/inserting-loading-data/insert-delayed), replication, the [query cache](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/query-cache) and the [event scheduler](https://mariadb.com/docs/server/server-usage/triggers-events/event-scheduler/events) are listed in:
* [Event Scheduler Thread States](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-states/event-scheduler-thread-states)
* [Query Cache Thread States](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-states/query-cache-thread-states)
* [Master Thread States](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-states/master-thread-states)
* [Slave Connection Thread States](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-states/slave-connection-thread-states)
* [Slave I/O Thread States](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-states/replica-io-thread-states)
* [Slave SQL Thread States](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-states/slave-sql-thread-states)
These correspond to the `STATE` values listed by the [SHOW PROCESSLIST](https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/show/show-processlist) statement or in the [Information Schema PROCESSLIST Table](https://mariadb.com/docs/server/reference/system-tables/information-schema/information-schema-tables/information-schema-processlist-table) as well as the `PROCESSLIST_STATE` value listed in the [Performance Schema threads Table](https://mariadb.com/docs/server/reference/system-tables/performance-schema/performance-schema-tables/performance-schema-threads-table)
| Value | Description |
| ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| After create | The function that created (or tried to create) a table (temporary or non-temporary) has just ended. |
| Analyzing | Calculating table key distributions, such as when running an [ANALYZE TABLE](https://mariadb.com/docs/server/reference/sql-statements/table-statements/analyze-table) statement. |
| checking permissions | Checking to see whether the permissions are adequate to perform the statement. |
| Checking table | [Checking](https://mariadb.com/docs/server/reference/sql-statements/table-statements/check-table) the table. |
| cleaning up | Preparing to reset state variables and free memory after executing a command. |
| closing tables | Flushing the changes to disk and closing the table. This state will only persist if the disk is full or under extremely high load. |
| converting HEAP to Aria | Converting an internal [MEMORY](https://mariadb.com/docs/server/server-usage/storage-engines/memory-storage-engine) temporary table into an on-disk [Aria](https://mariadb.com/docs/server/server-usage/storage-engines/aria) temporary table. |
| converting HEAP to MyISAM | Converting an internal [MEMORY](https://mariadb.com/docs/server/server-usage/storage-engines/memory-storage-engine) temporary table into an on-disk [MyISAM](https://mariadb.com/docs/server/server-usage/storage-engines/myisam-storage-engine) temporary table. |
| copy to tmp table | A new table has been created as part of an [ALTER TABLE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) statement, and rows are about to be copied into it. |
| Copying to group table | Sorting the rows by group and copying to a temporary table, which occurs when a statement has different [GROUP BY](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select#group-by) and [ORDER BY](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select#order-by) criteria. |
| Copying to tmp table | Copying to a temporary table in memory. |
| Copying to tmp table on disk | Copying to a temporary table on disk, as the resultset is too large to fit into memory. |
| Creating index | Processing an [ALTER TABLE ... ENABLE KEYS](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) for an [Aria](https://mariadb.com/docs/server/server-usage/storage-engines/aria) or [MyISAM](https://mariadb.com/docs/server/server-usage/storage-engines/myisam-storage-engine) table. |
| Creating sort index | Processing a [SELECT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select) statement resolved using an internal temporary table. |
| creating table | Creating a table (temporary or non-temporary). |
| Creating tmp table | Creating a temporary table (in memory or on-disk). |
| deleting from main table | Deleting from the first table in a multi-table [delete](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/delete), saving columns and offsets for use in deleting from the other tables. |
| deleting from reference tables | Deleting matched rows from secondary reference tables as part of a multi-table [delete](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/delete). |
| discard\_or\_import\_tablespace | Processing an [ALTER TABLE ... IMPORT TABLESPACE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) or [ALTER TABLE ... DISCARD TABLESPACE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) statement. |
| end | State before the final cleanup of an [ALTER TABLE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table), [CREATE VIEW](https://mariadb.com/docs/server/server-usage/views/create-view), [DELETE](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/delete), [INSERT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/inserting-loading-data/insert), [SELECT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select), or [UPDATE](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/update) statement. |
| executing | Executing a statement. |
| Execution of init\_command | Executing statements specified by the --init\_command [mariadb client](https://mariadb.com/docs/server/clients-and-utilities/mariadb-client/mariadb-command-line-client) option. |
| filling schema table | A table in the [information\_schema](https://mariadb.com/docs/server/reference/system-tables/information-schema) database is being built. |
| freeing items | Freeing items from the [query cache](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/query-cache) after executing a command. Usually followed by the cleaning up state. |
| Flushing tables | Executing a [FLUSH TABLES](https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/flush-commands/flush) statement and waiting for other threads to close their tables. |
| FULLTEXT initialization | Preparing to run a [full-text](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/optimization-and-indexes/full-text-indexes) search. This includes running the fulltext search (MATCH ... AGAINST) and creating a list of the result in memory |
| init | About to initialize an [ALTER TABLE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table), [DELETE](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/delete), [INSERT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/inserting-loading-data/insert), [SELECT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select), or [UPDATE](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/update) statement. Could be performaing [query cache](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/query-cache) cleanup, or flushing the [binary log](https://mariadb.com/docs/server/server-management/server-monitoring-logs/binary-log) or InnoDB log. |
| Killed | Thread will abort next time it checks the kill flag. Requires waiting for any locks to be released. |
| Locked | Query has been locked by another query. |
| logging slow query | Writing statement to the [slow query log](https://mariadb.com/docs/server/server-management/server-monitoring-logs/slow-query-log). |
| NULL | State used for [SHOW PROCESSLIST](https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/show/show-processlist). |
| login | Connection thread has not yet been authenticated. |
| manage keys | Enabling or disabling a table index. |
| Opening table\[s] | Trying to open a table. Usually very quick unless the limit set by [table\_open\_cache](https://mariadb.com/docs/server/server-management/variables-and-modes/server-system-variables#table_open_cache) has been reached, or an [ALTER TABLE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) or [LOCK TABLE](https://mariadb.com/docs/server/reference/sql-statements/transactions/lock-tables) is in progress. |
| optimizing | Server is performing initial optimizations in for a query. |
| preparing | State occurring during query optimization. |
| Purging old relay logs | Relay logs that are no longer needed are being removed. |
| query end | Query has finished being processed, but items have not yet been freed (the freeing items state. |
| Reading file | Server is reading the file (for example during [LOAD DATA INFILE](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/inserting-loading-data/load-data-into-tables-or-index/load-data-infile)). |
| Reading from net | Server is reading a network packet. |
| Removing duplicates | Duplicated rows being removed before sending to the client. This happens when SELECT DISTINCT is used in a way that the distinct operation could not be optimized at an earlier point. |
| removing tmp table | Removing an internal temporary table after processing a [SELECT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select) statement. |
| rename | Renaming a table. |
| rename result table | Renaming a table that results from an [ALTER TABLE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) statement having created a new table. |
| Reopen tables | Table is being re-opened after thread obtained a lock but the underlying table structure had changed, so the lock was released. |
| Repair by sorting | Indexes are being created with the use of a sort. Much faster than the related Repair with keycache. |
| Repair done | Multi-threaded repair has been completed. |
| Repair with keycache | Indexes are being created through the key cache, one-by-one. Much slower than the related Repair by sorting. |
| Rolling back | A transaction is being rolled back. |
| Saving state | New table state is being saved. For example, after, analyzing a [MyISAM](https://mariadb.com/docs/server/server-usage/storage-engines/myisam-storage-engine) table, the key distributions, rowcount etc. are saved to the .MYI file. |
| Searching rows for update | Finding matching rows before performing an [UPDATE](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/changing-deleting-data/update), which is needed when the UPDATE would change the index used for the UPDATE |
| Sending data | Sending data to the client as part of processing a [SELECT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select) statement or other statements that returns data like [INSERT ... RETURNING](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/inserting-loading-data/insertreturning) . Often the longest-occurring state as it also include all reading from tables and disk read activities. Where an aggregation or un-indexed filtering occurs there is significantly more rows read than what is sent to the client. |
| setup | Setting up an [ALTER TABLE](https://mariadb.com/docs/server/reference/sql-statements/data-definition/alter/alter-table) operation. |
| Sorting for group | Sorting as part of a [GROUP BY](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select#group-by) |
| Sorting for order | Sorting as part of an [ORDER BY](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select#order-by) |
| Sorting index | Sorting index pages as part of a table optimization operation. |
| Sorting result | Processing a [SELECT](https://mariadb.com/docs/server/reference/sql-statements/data-manipulation/selecting-data/select) statement using a non-temporary table. |
| statistics | Calculating statistics as part of deciding on a query execution plan. Usually a brief state unless the server is disk-bound. |
| System lock | Requesting or waiting for an external lock for a specific table. The [storage engine](https://mariadb.com/docs/server/server-usage/storage-engines) determines what kind of external lock to use. For example, the [MyISAM](https://mariadb.com/docs/server/server-usage/storage-engines/myisam-storage-engine) storage engine uses file-based locks. However, MyISAM's external locks are disabled by default, due to the default value of the [skip\_external\_locking](https://mariadb.com/docs/server/server-management/variables-and-modes/server-system-variables#skip_external_locking) system variable. Transactional storage engines such as [InnoDB](https://mariadb.com/docs/server/server-usage/storage-engines/innodb) also register the transaction or statement with MariaDB's [transaction coordinator](https://mariadb.com/docs/server/server-management/server-monitoring-logs/transaction-coordinator-log) while in this thread state. See [MDEV-19391](https://jira.mariadb.org/browse/MDEV-19391) for more information about that. |
| Table lock | About to request a table's internal lock after acquiring the table's external lock. This thread state occurs after the System lock thread state. |
| update | About to start updating table. |
| Updating | Searching for and updating rows in a table. |
| updating main table | Updating the first table in a multi-table update, and saving columns and offsets for use in the other tables. |
| updating reference tables | Updating the secondary (reference) tables in a multi-table update |
| updating status | This state occurs after a query's execution is complete. If the query's execution time exceeds [long\_query\_time](https://mariadb.com/docs/server/server-management/variables-and-modes/server-system-variables#long_query_time), then [Slow\_queries](https://mariadb.com/docs/server/server-management/variables-and-modes/server-status-variables#slow_queries) is incremented, and if the [slow query log](https://mariadb.com/docs/server/server-management/server-monitoring-logs/slow-query-log) is enabled, then the query is logged. If the [SERVER\_AUDIT](https://mariadb.com/docs/server/reference/plugins/mariadb-audit-plugin) plugin is enabled, then the query is also logged into the audit log at this stage. If the [userstats](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/statistics-for-optimizing-queries/user-statistics) plugin is enabled, then CPU statistics are also updated at this stage. |
| User lock | About to request or waiting for an advisory lock from a [GET LOCK()](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/get_lock) call. For [SHOW PROFILE](https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/show/show-profile), means requesting a lock only. |
| User sleep | A [SLEEP()](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/sleep) call has been invoked. |
| Waiting for commit lock | [FLUSH TABLES WITH READ LOCK](https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/flush-commands/flush) is waiting for a commit lock, or a statement resulting in an explicit or implicit commit is waiting for a read lock to be released. This state was called Waiting for all running commits to finish in earlier versions. |
| Waiting for global read lock | Waiting for a global read lock. |
| Waiting for table level lock | External lock acquired,and internal lock about to be requested. Occurs after the System lock state. In earlier versions, this was called Table lock. |
| Waiting for xx lock | Waiting to obtain a lock of type xx. |
| Waiting on cond | Waiting for an unspecified condition to occur. |
| Writing to net | Writing a packet to the network. |
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