MDEV-17554 Auto-create new partition for system versioned tables with history partitioned by INTERVAL/LIMIT

:: Syntax change ::

Keyword AUTO enables history partition auto-creation.

Examples:

    CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
    PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;

    CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
    PARTITION BY SYSTEM_TIME INTERVAL 1 MONTH
    STARTS '2021-01-01 00:00:00' AUTO PARTITIONS 12;

    CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
    PARTITION BY SYSTEM_TIME LIMIT 1000 AUTO;

Or with explicit partitions:

    CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
    PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO
    (PARTITION p0 HISTORY, PARTITION pn CURRENT);

To disable or enable auto-creation one can use ALTER TABLE by adding
or removing AUTO from partitioning specification:

    CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
    PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;

    # Disables auto-creation:
    ALTER TABLE t1 PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR;

    # Enables auto-creation:
    ALTER TABLE t1 PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;

If the rest of partitioning specification is identical to CREATE TABLE
no repartitioning will be done (for details see MDEV-27328).

:: Description ::

Before executing history-generating DML command (see the list of commands below)
add N history partitions, so that N would be sufficient for potentially
generated history. N > 1 may be required when history partitions are switched
by INTERVAL and current_timestamp is N times further than the interval
boundary of the last history partition.

If the last history partition equals or exceeds LIMIT records then new history
partition is created and selected as the working partition. According to
MDEV-28411 partitions cannot be switched (or created) while the command is
running. Thus LIMIT does not carry strict limitation and the history partition
size must be planned as LIMIT value plus average number of history one DML
command can generate.

Auto-creation is implemented by synchronous fast_alter_partition_table() call
from the thread of the executed DML command before the command itself is run
(by the fallback and retry mechanism similar to Discovery feature,
see Open_table_context).

The name for newly added partitions are generated like default partition names
with extension of MDEV-22155 (which avoids name clashes by extending assignment
counter to next free-enough gap).

These DML commands can trigger auto-creation:

    DELETE (including multitable DELETE, excluding DELETE HISTORY)
    UPDATE (including multitable UPDATE)
    REPLACE (including REPLACE .. SELECT)
    INSERT .. ON DUPLICATE KEY UPDATE (including INSERT .. SELECT .. ODKU)
    LOAD DATA .. REPLACE

:: Bug fixes ::

MDEV-23642 Locking timeout caused by auto-creation affects original DML

    The reasons for this are:

    - Do not disrupt main business process (the history is auxiliary service);

    - Consequences are non-fatal (history is not lost, but comes into wrong
      partition; fixed by partitioning rebuild);

    - There is more freedom for application to fail in this case or not: it may
      read warning info and find corresponding error number.

    - While non-failing command is easy to handle by an application and fail it,
      the opposite is hard to handle: there is no automatic actions to fix
      failed command and retry, DBA intervention is required and until then
      application is non-functioning.

MDEV-23639 Auto-create does not work under LOCK TABLES or inside triggers

    Don't do tdc_remove_table() for OT_ADD_HISTORY_PARTITION because it is
    not possible in locked tables mode.

    LTM_LOCK_TABLES mode (and LTM_PRELOCKED_UNDER_LOCK_TABLES) works out
    of the box as fast_alter_partition_table() can reopen tables via
    locked_tables_list.

    In LTM_PRELOCKED we reopen and relock table manually.

:: More fixes ::

* some_table_marked_for_reopen flag fix

  some_table_marked_for_reopen affets only reopen of
  m_locked_tables. I.e. Locked_tables_list::reopen_tables() reopens only
  tables from m_locked_tables.

* Unused can_recover_from_failed_open() condition

  Is recover_from_failed_open() can be really used after
  open_and_process_routine()?

:: Reviewed by ::

Sergei Golubchik <serg@mariadb.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/sql/sql_base.h b/sql/sql_base.h
index c593d85b5e7..06d75596827 100644
--- a/sql/sql_base.h
+++ b/sql/sql_base.h
@@ -533,7 +533,8 @@ public:
     OT_BACKOFF_AND_RETRY,
     OT_REOPEN_TABLES,
     OT_DISCOVER,
-    OT_REPAIR
+    OT_REPAIR,
+    OT_ADD_HISTORY_PARTITION
   };
   Open_table_context(THD *thd, uint flags);
 
@@ -606,6 +607,9 @@ private:
     protection against global read lock.
   */
   mdl_bitmap_t m_has_protection_against_grl;
+
+public:
+  uint vers_create_count;
 };