The fix is in replacing the waiting for the whole purge finishing
with the the waiting for only delete-marked records purging finishing.
Reviewed by: Marko Mäkelä
- InnoDB bulk insert operation aborts the server for redundant
table. InnoDB miscalculates the record size in temporary file
for the redundant table. CHAR in redundant row format table
always fixed length, but in temporary file, it is variable-length
for variable-length character sets.
- When foreign_key_check is disabled, allowing to modify the
column which is part of foreign key constraint can lead to
refusal of TRUNCATE TABLE, OPTIMIZE TABLE later. So it make
sense to block the column modify operation when foreign key
is involved irrespective of foreign_key_check variable.
Correct way to modify the charset of the column when fk is involved:
SET foreign_key_checks=OFF;
ALTER TABLE child DROP FOREIGN KEY fk, MODIFY m VARCHAR(200) CHARSET utf8mb4;
ALTER TABLE parent MODIFY m VARCHAR(200) CHARSET utf8mb4;
ALTER TABLE child ADD CONSTRAINT FOREIGN KEY (m) REFERENCES PARENT(m);
SET foreign_key_checks=ON;
fk_check_column_changes(): Remove the FOREIGN_KEY_CHECKS while
checking the column change for foreign key constraint. This
is the partial revert of commit 5f1f2fc0e4
and it changes the behaviour of copy alter algorithm
ha_innobase::prepare_inplace_alter_table(): Find the modified
column and check whether it is part of existing and newly
added foreign key constraint.
- InnoDB throws ASAN error while adding the index on virtual column
of system versioned table. InnoDB wrongly assumes that virtual
column collation type changes, creates new column with different
character set. This leads to failure while detaching the column
from indexes.
purge_sys_t::sees(): Wrapper for view.sees().
trx_purge_truncate_history(): Invoke purge_sys.sees() instead of
comparing to head.trx_no, to determine if undo pages can be safely freed.
The test innodb.cursor-restore-locking was adjusted by Vladislav Lesin,
as was the the debug instrumentation in row_purge_del_mark().
Reviewed by: Vladislav Lesin
Adding tests demonstrating that columns:
- mysql.innodb_table_stats.last_update
- mysql.innodb_index_stats.last_update
contain sane values close to NOW() rathar than a garbage.
Tests cover these three underlying TIMESTAMP data formats:
- MariaDB Field_timestamp0 - UINT4 based
Like in a MariaDB native installation running with mysql56_temporal_format=0
- MariaDB Field_timestampf - BINARY(4) based, with UNSIGNED_FLAG
Like in a MariaDB native installation running with mysql56_temporal_format=1
- MySQL-alike Field_timestampf - BINARY(4) based, without UNSIGNED_FLAG
Like with a MariaDB server running over a MySQL-5.6 directory
(e.g. during a migragion).
rw_trx_hash_t::find() acquires element->mutex, then unpins pins, used for
lf_hash element search. After that the "element" can be deallocated and
reused by some other thread.
If we take a look rw_trx_hash_t::insert()->lf_hash_insert()->lf_alloc_new()
calls, we will not find any element->mutex acquisition, as it was not
initialized yet before it's allocation. rw_trx_hash_t::insert() can reuse
the chunk, unpinned in rw_trx_hash_t::find().
The scenario is the following:
1. Thread 1 have just executed lf_hash_search() in
rw_trx_hash_t::find(), but have not acquired element->mutex yet.
2. Thread 2 have removed the element from hash table with
rw_trx_hash_t::erase() call.
3. Thread 1 acquired element->mutex and unpinned pin 2 pin with
lf_hash_search_unpin(pins) call.
4. Some thread purged memory of the element.
5. Thread 3 reused the memory for the element, filled element->id,
element->trx.
6. Thread 1 crashes with failed "DBUG_ASSERT(trx_id == trx->id)"
assertion.
Note that trx_t objects are also reused, see the code around trx_pools
for details.
The fix is to invoke "lf_hash_search_unpin(pins);" after element->trx is
stored in local variable in rw_trx_hash_t::find().
Reviewed by: Nikita Malyavin, Marko Mäkelä.
Let us remove explicit updates of MONITOR_NUM_UNDO_SLOT_USED
and MONITOR_NUM_UNDO_SLOT_CACHED, and let us compute the rough values
from trx_sys.rseg_array[] on demand.
stored externally
row_merge_buf_add(): Has strict assert that fixed length mismatch
shouldn't happen while rebuilding the redundant row format table
btr_index_rec_validate(): Fixed size column can be stored externally.
So sum of inline stored length and external stored length of the
column should be equal to total column length
In MariaDB, we have a confusing problem where:
* The transaction_isolation option can be set in a configuration file, but it cannot be set dynamically.
* The tx_isolation system variable can be set dynamically, but it cannot be set in a configuration file.
Therefore, we have two different names for the same thing in different contexts. This is needlessly confusing, and it complicates the documentation. The same thing applys for transaction_read_only.
MySQL 5.7 solved this problem by making them into system variables. https://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-20.html
This commit takes a similar approach by adding new system variables and marking the original ones as deprecated. This commit also resolves some legacy problems related to SET STATEMENT and transaction_isolation.
