:: 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>
column generated using date_format() and if()
vcol_info->expr is allocated on expr_arena at parsing stage. Since
expr item is allocated on expr_arena all its containee items must be
allocated on expr_arena too. Otherwise fix_session_expr() will
encounter prematurely freed item.
When table is reopened from cache vcol_info contains stale
expression. We refresh expression via TABLE::vcol_fix_exprs() but
first we must prepare a proper context (Vcol_expr_context) which meets
some requirements:
1. As noted above expr update must be done on expr_arena as there may
be new items created. It was a bug in fix_session_expr_for_read() and
was just not reproduced because of no second refix. Now refix is done
for more cases so it does reproduce. Tests affected: vcol.binlog
2. Also name resolution context must be narrowed to the single table.
Tested by: vcol.update main.default vcol.vcol_syntax gcol.gcol_bugfixes
3. sql_mode must be clean and not fail expr update.
sql_mode such as MODE_NO_BACKSLASH_ESCAPES, MODE_NO_ZERO_IN_DATE, etc
must not affect vcol expression update. If the table was created
successfully any further evaluation must not fail. Tests affected:
main.func_like
Reviewed by: Sergei Golubchik <serg@mariadb.org>
1. moved fix_vcol_exprs() call to open_table()
mysql_alter_table() doesn't do lock_tables() so it cannot win from
fix_vcol_exprs() from there. Tests affected: main.default_session
2. Vanilla cleanups and comments.
records_are_comparable() requires this condition:
bitmap_is_subset(table->write_set, table->read_set)
On first iteration vers_update_fields() changes write_set and
read_set. On second iteration the above condition fails.
Added missing read bit for ROW_START. Also reorganized
bitmap_set_bit() so it is called only when needed.
Throw ER_NOT_FORM_FILE if this is wrong FRM data (warning with
ER_VERS_FIELD_WRONG_TYPE is still printed for deeper knowledge of what
was happened).
Keep ER_VERS_FIELD_WRONG_TYPE for creating partitioned table with
trx-versioning. Tested by MDEV-15951 in trx_id.test
TYPELIBs for ENUM/SET columns could erroneously undergo redundant
hex-unescaping at the table open time.
Fix:
- Prevent multiple unescaping of the same TYPELIB
- Prevent sharing TYPELIBs between columns with different mbminlen
extra2_read_len resolved by keeping the implementation
in sql/table.cc by exposed it for use by ha_partition.cc
Remove identical implementation in unireg.h
(ref: bfed2c7d57)
whenever possible, partitioning should use the full
partition plugin name, not the one byte legacy code.
Normally, ha_partition can get the engine plugin from
table_share->default_part_plugin.
But in some cases, e.g. in DROP TABLE, the table isn't
opened, table_share is NULL, and ha_partition has to parse
the frm, much like dd_frm_type() does.
temporary_tables.cc, sql_table.cc:
When dropping a table, it must be deleted in the engine
first, then frm file. Because frm can be the only true
source of metadata that the engine might need for DROP.
table.cc:
when opening a partitioned table, if the engine for
partitions is not found, do not fallback to MyISAM.
Make it possible to specify engine-defined attributes on partitions
as well as tables.
If an engine-defined attribute is only specified at the table level,
it applies to all the partitions in the table.
This is a backward-compatible behavior.
If the same attribute is specified both at the table level and the
partition level, the per-partition one takes precedence.
So, we can consider per-table attributes as default values.
One cannot specify engine-defined attributes on subpartitions.
Implementation details:
* We store per-partition attributes in the partition_element class
because we already have the part_comment field, which is for
per-partition comments.
* In the case of ALTER TABLE statements, the partition_elements in
table->part_info is set up by mysql_unpack_partition().
So, we parse per-partition attributes after the call of the function.
Update was skipped (need_update was false) because compare_record()
used HA_PARTIAL_COLUMN_READ branch and it skipped row_start check
has_explicit_value() was false. When we set bit for row_start in
has_value_set the row is updated with new row_start value.
The bug was caused by combination of MDEV-23446 and 3789692d17. The
latter one says:
... But generated columns that are written to the table are always
deterministic and cannot change unless normal non-generated columns
were changed. ...
Since MDEV-23446 generated row_start can change while non-generated
columns are not changed.
Explicit value flag came from HAS_EXPLICIT_DEFAULT which was used to
distinguish default-generated value from user-supplied one.
Re-execution of a query containing subquery in the FROM clause results
in assert failure in case the query is run as part of a stored routine or
as a prepared statement AND derived table merge optimization is off.
As an example, the following test case
CREATE TABLE t1 (a INT) ;
CREATE PROCEDURE sp() SELECT * FROM (SELECT a FROM t1) tb;
CALL sp();
SET optimizer_switch='derived_merge=off';
CALL sp();
results in assert failure on the second invocation of the 'sp' stored routine.
The reason for assertion failure is that the expression
derived->is_excluded()
returns the value true where the value false expected.
The method is_excluded() returns the value true for a derived table
that has been merged to a parent select. Such transformation happens as part
of Derived Table Merge Optimization that is performed on first invocation of
a stored routine or a prepared statement containing a query with subquery
in the FROM clause of the main SELECT.
When the same routine or prepared statement is run the second time and
Derived Table Merge Optimization is OFF the MariaDB server tries to materialize
a derived table specified by the subquery that fails since this subquery
has already been merged to the top-most SELECT. This transformation is permanent
and can't be reverted. That is the reason why the assert
DBUG_ASSERT(!derived->is_excluded());
fails inside the function TABLE_LIST::set_check_materialized().
Similar behaviour can be observed in case a stored routine or prepared statement
containing a SELECT statement with subquery in the FROM clause, first is run
with the optimizer_switch option set to derived_merge=off and re-run after this
option has been switched to derived_merge=on. In this case a derived table for
subquery is materialized on the first execution and marked as merged derived
table on the second execution that results in error with misleading error
message:
MariaDB [test]> CALL sp1();
ERROR 1030 (HY000): Got error 1 "Operation not permitted" from storage engine MEMORY
To fix the issue, a derived table that has been already optimized shouldn't be
re-marked for one more round of optimization.
One significant consequence following from suggested change is that the data
member TABLE_LIST::derived_type is not updated once the table optimization
has been done. This fact should be taken into account when Prepared Statement
being handled since once a table listed in a query has been optimized on
execution of the statement PREPARE FROM it won't be touched anymore on handling
the statement EXECUTE.
One side effect caused by this change could be observed for the following
test case:
CREATE TABLE t1 (s1 INT);
CREATE VIEW v1 AS
SELECT s1,s2 FROM (SELECT s1 as s2 FROM t1 WHERE s1 <100) x, t1 WHERE t1.s1=x.s2;
INSERT INTO v1 (s1) VALUES (-300);
PREPARE stmt FROM "INSERT INTO v1 (s1) VALUES (-300)";
EXECUTE stmt;
Execution of the above EXECUTE statement results in issuing the error
ER_COLUMNACCESS_DENIED_ERROR since table_ref->is_merged_derived() is false
and check_column_grant_in_table_ref() called for a temporary table that
shouldn't be. To fix this issue the function find_field_in_tables has been
modified in such a way that the function check_column_grant_in_table_ref()
is not called for a temporary table.
InnoDB fails to apply buffered insert operation for
'mysql/transaction_registry' table during system versioning DDL.
To avoid this, DDL calls extra(HA_EXTRA_IGNORE_INSERT) to
inform the InnoDB for applying the buffered insert operation.
Long UNIQUE HASH index silently creates virtual column index, which should
be impossible for base columns featuring AUTO_INCREMENT.
Fix: add a relevant check; add new vcol type for a prettier error message.
In commit 1811fd51fb the assertion
should have said error_reported instead of !error_reported.
But, that revised assertion would still fail in main.defaults
where ER_BAD_DATA is reported during CREATE TABLE.
This is a duplicate of MDEV-18278 89936f11e9, but I will add an
additional assertion
Description:
The frm corruption should not be reported during CREATE TABLE. Normally
it doesn't, and the data to fill TABLE is taken by open_table_from_share
call. However, the vcol data is stored as SQL string in
table->s->vcol_defs.str and is anyway parsed on each table open.
It is impossible [or hard] to avoid, because it's hard to clone the
expression tree in general (it's easier to parse).
Normally parse_vcol_defs should only fail on semantic errors. If so,
error_reported is set to true. Any other failure is not expected during
table creation. There is either unhandled/unacknowledged error, or
something went really wrong, like memory reject. This all should be
asserted anyway.
Solution:
* Set *error_reported=true for the forward references check;
* Assert for every unacknowledged error during table creation.
There were two independent problems which lead to the crash
and to the non-relevant records returned in I_S queries:
- The code in the I_S implementation was not secure
about values with 0x00 bytes.
It's fixed by using check_db_name() and check_table_name()
inside make_table_name_list(), and by adding the test for
0x00 inside check_table_name().
- The code in Item_string::print() did not convert
strings without introducers when restoring
the CREATE VIEW statement from an Item tree.
This made wrong literals inside the "query" line in the view FRM file
in cases when the VIEW parse time
character_set_client!=character_set_connection.
That's fixed by adding a proper conversion.
This change also fixed a similar problem in SHOW PROCEDURE CODE -
the literals were displayed in wrong character set in SP instructions
in cases when the SP parse time
character_set_client!=character_set_connection.
