prep_alter_part_table upon re-partitioning by system time
memcmp() tries to compare beyond the last member of interval because
sizeof(Vers_part_info::interval) is 80. It is sizeof of variable,
sizeof of type is 76.
Now we compare interval_t struct C++ way.
This patch is the result of running
run-clang-tidy -fix -header-filter=.* -checks='-*,modernize-use-equals-default' .
Code style changes have been done on top. The result of this change
leads to the following improvements:
1. Binary size reduction.
* For a -DBUILD_CONFIG=mysql_release build, the binary size is reduced by
~400kb.
* A raw -DCMAKE_BUILD_TYPE=Release reduces the binary size by ~1.4kb.
2. Compiler can better understand the intent of the code, thus it leads
to more optimization possibilities. Additionally it enabled detecting
unused variables that had an empty default constructor but not marked
so explicitly.
Particular change required following this patch in sql/opt_range.cc
result_keys, an unused template class Bitmap now correctly issues
unused variable warnings.
Setting Bitmap template class constructor to default allows the compiler
to identify that there are no side-effects when instantiating the class.
Previously the compiler could not issue the warning as it assumed Bitmap
class (being a template) would not be performing a NO-OP for its default
constructor. This prevented the "unused variable warning".
For commands
(1) alter table t1 add partition (partition p2);
(2) alter table t1 add partition (partition px history);
It printed the same error message:
Wrong partitioning type, expected type: `SYSTEM_TIME`
For (1) it is not clear from the syntax that we are trying to add
HASH partition. For (2) it is not clear that the table partitioning is
different than SYSTEM_TIME. Now it prints what type we are trying to
add to what type of partitioning.
Fixed warning unused function rename_field_in_list() for compilation
without partitioning.
For commands
(1) alter table t1 add partition (partition p2);
(2) alter table t1 add partition (partition px history);
It printed the same error message:
Wrong partitioning type, expected type: `SYSTEM_TIME`
For (1) it is not clear from the syntax that we are trying to add
HASH partition. For (2) it is not clear that the table partitioning is
different than SYSTEM_TIME. Now it prints what type we are trying to
add to what type of partitioning.
10.5 part: test cases and comments.
The code is in the merge commit 74fe1c44aa
When f.ex. table is partitioned by HASH(a) and we rename column `a' to
`b' partitioning filter stays unchanged: HASH(a). That's the wrong
behavior.
The patch updates partitioning filter in accordance to the new columns
names. That includes partition/subpartition expression and
partition/subpartition field list.
:: 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>
When we need to add/remove or change LIMIT, INTERVAL, AUTO we have to
recreate partitioning from scratch (via data copy). Such operations
should be done fast. To remove options like LIMIT or INTERVAL one
should write:
alter table t1 partition by system_time;
The command checks whether it is new or existing SYSTEM_TIME
partitioning. And in the case of new it behaves as CREATE would do:
adds default number of partitions (2). If SYSTEM_TIME partitioning
already existed it just changes its options: removes unspecified ones
and adds/changes those specified explicitly. In case when partitions
list was supplied it behaves as usual: does full repartitioning.
Examples:
create or replace table t1 (x int) with system versioning
partition by system_time limit 100 partitions 4;
# Change LIMIT
alter table t1 partition by system_time limit 33;
# Remove LIMIT
alter table t1 partition by system_time;
# This does full repartitioning
alter table t1 partition by system_time limit 33 partitions 4;
# This does data copy as pruning will require records in correct partitions
alter table t1 partition by system_time interval 1 hour
starts '2000-01-01 00:00:00';
# But this works fast, LIMIT will apply to DML commands
alter table t1 partition by system_time limit 33;
To sum up, ALTER for SYSTEM_TIME partitioning does full repartitioning
when:
- INTERVAL was added or changed;
- partition list or partition number was specified;
Otherwise it does fast alter table.
Cleaned up dead condition in set_up_default_partitions().
Reviewed by:
Oleksandr Byelkin <sanja@mariadb.com>
Nikita Malyavin <nikitamalyavin@gmail.com>
Moved LIMIT warning from vers_set_hist_part() to new call
vers_check_limit() at table unlock phase. At that point
read_partitions bitmap is already pruned by DML code (see
prune_partitions(), find_used_partitions()) so we have to set
corresponding bits for working history partition.
Also we don't do my_error(ME_WARNING|ME_ERROR_LOG), because at that
point it doesn't update warnings number, so command reports 0 warnings
(but warning list is still updated). Instead we do
push_warning_printf() and sql_print_warning() separately.
Under LOCK TABLES external_lock(F_UNLCK) is not executed. There is
start_stmt(), but no corresponding "stop_stmt()". So for that mode we
call vers_check_limit() directly from close_thread_tables().
Test result has been changed according to new LIMIT and warning
printing algorithm. For convenience all LIMIT warnings are marked with
"You see warning above ^".
TODO MDEV-20345 fixed. Now vers_history_generating() contains
fine-grained list of DML-commands that can generate history (and TODO
mechanism worked well).
LIMIT history switching requires the number of history partitions to
be marked for read: from first to last non-empty plus one empty. The
least we can do is to fail with error message if the needed partition
was not marked for read. As this is handler interface we require new
handler error code to display user-friendly error message.
Switching by INTERVAL works out-of-the-box with
ER_ROW_DOES_NOT_MATCH_GIVEN_PARTITION_SET error.
Dead code cleanup:
part_info->num_parts usage was wrong and working incorrectly in
mysql_drop_partitions() because num_parts is already updated in
prep_alter_part_table(). We don't have to update part_info->partitions
because part_info is destroyed at alter_partition_lock_handling().
Cleanups:
- DBUG_EVALUATE_IF() macro replaced by shorter form DBUG_IF();
- Typo in ER_KEY_COLUMN_DOES_NOT_EXITS.
Refactorings:
- Splitted write_log_replace_delete_frm() into write_log_delete_frm()
and write_log_replace_frm();
- partition_info via DDL_LOG_STATE;
- set_part_info_exec_log_entry() removed.
DBUG_EVALUATE removed
DBUG_EVALUTATE was only added for consistency together with
DBUG_EVALUATE_IF. It is not used anywhere in the code.
DBUG_SUICIDE() fix on release build
On release DBUG_SUICIDE() was statement. It was wrong as
DBUG_SUICIDE() is used in expression context.
When there are E empty partitions left, auto-create N new empty
partitions for SYSTEM_TIME partitioning rotated by INTERVAL/LIMIT and
marked by AUTO_INCREMENT keyword. Syntax change: AUTO_INCREMENT
keyword (or shorter AUTO may be used instead) after LIMIT/INTERVAL
clause.
CREATE OR REPLACE TABLE t (x INT) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME LIMIT 100000 AUTO_INCREMENT;
CREATE OR REPLACE TABLE t (x INT) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME INTERVAL 1 WEEK AUTO_INCREMENT;
The current revision implements hard-coded values of 1 for E and N. As
well as auto-creation threshold MinInterval = 1 hour, MinLimit = 1000.
The name for newly added partition will be first chosen as "pX", where
X is partition number and "p" is hard-coded name prefix. If this name
is already occupied, the X will be incremented until the resulting
name will be free to use.
ALTER TABLE ADD PARTITION is now always fast. If there some history
partition overflow occurs manual ALTER TABLE REBUILD PARTITION is
needed.
* Explicit STARTS syntax
* SHOW CREATE
* Default STARTS rounding depending on INTERVAL type
* Warn when STARTS timestamp is later than query time
* Fix uninitialized Lex->create_last_non_select_table under
mysql_unpack_partition()
Default STARTS rounding depending on INTERVAL type
If STARTS clause is omitted, default one is assigned with value
derived from query timestamp. The rounding is done on STARTS value
depending on INTERVAL type:
SECOND: no rounding is done;
MINUTE: timestamp seconds is set to 0;
HOUR: timestamp seconds and minutes are set to 0;
DAY, WEEK, MONTH and YEAR: timestamp seconds, minutes and hours are
set to 0 (the date of rotation is kept as current date).
SYSTEM_TYPE partitioning: COLUMN properties removed. Partitioning is
now pure RANGE based on UNIX_TIMESTAMP(row_end).
DECIMAL type is now allowed as RANGE partitioning, we can partition by
UNIX_TIMESTAMP() (but not for DATETIME which depends on local timezone
of course).
