Instead of updating global counter, calculate Threads_running on the fly.
All threads having command != COM_SLEEP are included.
Behaviour changes:
Previously SHOW STATUS and SHOW GLOBAL STATUS returned the same values
representing global status. Now SHOW STATUS always returns 1 indicating that
current session has 1 thread running.
Previously only threads that were executing dispatch_command() or running events
were accounted by Threads_running. Now it is rough equivalent of
SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST WHERE state!='Sleep'
LOCK_thd_data was used to protect both THD data and
ensure that the THD is not deleted while it was in use
This patch moves the THD delete protection to LOCK_thd_kill,
which already protects the THD for kill.
The benefits are:
- More well defined what LOCK_thd_data protects
- LOCK_thd_data usage is now much simpler and easier to verify
- Less chance of deadlocks in SHOW PROCESS LIST as there is less
chance of interactions between mutexes
- Remove not needed LOCK_thread_count from
thd_get_error_context_description()
- Fewer mutex taken for thd->awake()
Other things:
- Don't take mysys->var mutex in show processlist to check if thread
is kill marked
- thd->awake() now automatically takes the LOCK_thd_kill mutex
(Simplifies code)
- Apc uses LOCK_thd_kill instead of LOCK_thd_data
THD::vers_update_trt, trx_t::vers_update_trt, trx_savept_t::vers_update_trt:
Remove. Instead, determine from trx_t::mod_tables whether versioned
columns were affected by the transaction.
handlerton::prepare_commit_versioned: Replaces vers_get_trt_data.
Return the transaction start ID and also the commit ID, in case
the transaction modified any system-versioned columns (0 if not).
TR_table::store_data(): Remove (merge with update() below).
TR_table::update(): Add the parameters start_id, end_id.
ha_commit_trans(): Remove a condition on SQLCOM_ALTER_TABLE.
If we need something special for ALTER TABLE...ALGORITHM=INPLACE,
that can be done inside InnoDB by modifying trx_t::mod_tables.
innodb_prepare_commit_versioned(): Renamed from innodb_get_trt_data().
Check trx_t::mod_tables to see if any changes to versioned columns
are present.
trx_mod_table_time_t: A pair of logical timestamps, replacing the
undo_no_t in trx_mod_tables_t. Keep track of not only the first
modification to a persistent table in each transaction, but also
the first modification of a versioned column in a table.
dtype_t, dict_col_t: Add the accessor is_any_versioned(), to check
if the type refers to a system-versioned user or system column.
upd_t::affects_versioned(): Check if an update affects a versioned
column.
trx_undo_report_row_operation(): If a versioned column is affected
by the update, invoke trx_mod_table_time_t::set_versioned().
trx_rollback_to_savepoint_low(): If all changes to versioned columns
were rolled back, invoke trx_mod_table_time_t::rollback_versioned(),
so that trx_mod_table_time_t::is_versioned() will no longer hold.
The background is that one user had a lot of views and using some complex
queries on information schema temporary memory of more than 2G was used.
- Added new element 'total_alloc' to MEM_ROOT for easier debugging.
- Added MAX_MEMORY_USED to information_schema.processlist.
- Added new status variable "Memory_used_initial" that shows how much MariaDB
uses at startup. This gives the base value for "Memory_used".
- Reuse memory continuously for information schema queries instead of
only freeing memory at query end.
Other things
- Removed some not needed set_notnull() calls for not null columns.
As a result of this merge the code for the following tasks appears in 10.3:
- MDEV-12172 Implement tables specified by table value constructors
- MDEV-12176 Transform [NOT] IN predicate with long list of values INTO
[NOT] IN subquery.
Moving a few methods from sp_rcontext to different classes:
- Table_ident::resolve_table_rowtype_ref
- Qualified_column_ident::resolve_type_ref
- Row_definition_list::resolve_table_rowtype_ref
- Row_definition_list::adjust_formal_params_to_actual_params
It easier to reuse these methods this way in the future.
followup for 97c2a7354b - don't use thd->is_error(),
the error could've been set before TABLE_LIST::cleanup_items.
Use the error handler to count errors.
This fixes rpl.rpl_row_binlog_max_cache_size - it was failing when
ER_STMT_CACHE_FULL happened duing multi-table update. Because
multi_update::abort_result_set() calls do_updates() to update
as much as possible, so one cannot rely on thd->is_error() after that.
- Added missing delete thd in bootstrap()
- Delete wrong 'delete thd' in start_wsrep_THD()
- Added missing 'delete thd' in case of SCHEDULER_ONE_THREAD_PER_CONNECTION
- Delete wrong dec_thread_running() in destroy_thd() as it caused thread_running
to be wrong.
- Moved reset_killed() to a normal function to make it easier to debug
- Added check of mutex in wsrep_aborting_thd... functions
