Under unknown circumstances, the SQL layer may wrongly disregard an
invocation of thd_mark_transaction_to_rollback() when an InnoDB
transaction had been aborted (rolled back) due to one of the following errors:
* HA_ERR_LOCK_DEADLOCK
* HA_ERR_RECORD_CHANGED (if innodb_snapshot_isolation=ON)
* HA_ERR_LOCK_WAIT_TIMEOUT (if innodb_rollback_on_timeout=ON)
Such an error used to cause a crash of InnoDB during transaction commit.
These changes aim to catch and report the error earlier, so that not only
this crash can be avoided but also the original root cause be found and
fixed more easily later.
The idea of this fix is from Michael 'Monty' Widenius.
HA_ERR_ROLLBACK: A new error code that will be translated into
ER_ROLLBACK_ONLY, signalling that the current transaction
has been aborted and the only allowed action is ROLLBACK.
trx_t::state: Add TRX_STATE_ABORTED that is like
TRX_STATE_NOT_STARTED, but noting that the transaction had been
rolled back and aborted.
trx_t::is_started(): Replaces trx_is_started().
ha_innobase: Check the transaction state in various places.
Simplify the logic around SAVEPOINT.
ha_innobase::is_valid_trx(): Replaces ha_innobase::is_read_only().
The InnoDB logic around transaction savepoints, commit, and rollback
was unnecessarily complex and might have contributed to this
inconsistency. So, we are simplifying that logic as well.
trx_savept_t: Replace with const undo_no_t*. When we rollback to
a savepoint, all we need to know is the number of undo log records
that must survive.
trx_named_savept_t, DB_NO_SAVEPOINT: Remove. We can store undo_no_t
directly in the space allocated at innobase_hton->savepoint_offset.
fts_trx_create(): Do not copy previous savepoints.
fts_savepoint_rollback(): If a savepoint was not found, roll back
everything after the default savepoint of fts_trx_create().
The test innodb_fts.savepoint is extended to cover this code.
Reviewed by: Vladislav Lesin
Tested by: Matthias Leich
In MDEV-515, we enabled an optimization where an insert into an
empty table will use table-level locking and undo logging.
This may break applications that expect row-level locking.
The SQL statements created by the mysqldump utility will include the
following:
SET unique_checks=0, foreign_key_checks=0;
We will use these flags to enable the table-level locked and logged
insert. Unless the parameters are set, INSERT will be executed in
the old way, with row-level undo logging and implicit record locks.
We implement an idea that was suggested by Michael 'Monty' Widenius
in October 2017: When InnoDB is inserting into an empty table or partition,
we can write a single undo log record TRX_UNDO_EMPTY, which will cause
ROLLBACK to clear the table.
For this to work, the insert into an empty table or partition must be
covered by an exclusive table lock that will be held until the transaction
has been committed or rolled back, or the INSERT operation has been
rolled back (and the table is empty again), in lock_table_x_unlock().
Clustered index records that are covered by the TRX_UNDO_EMPTY record
will carry DB_TRX_ID=0 and DB_ROLL_PTR=1<<55, and thus they cannot
be distinguished from what MDEV-12288 leaves behind after purging the
history of row-logged operations.
Concurrent non-locking reads must be adjusted: If the read view was
created before the INSERT into an empty table, then we must continue
to imagine that the table is empty, and not try to read any records.
If the read view was created after the INSERT was committed, then
all records must be visible normally. To implement this, we introduce
the field dict_table_t::bulk_trx_id.
This special handling only applies to the very first INSERT statement
of a transaction for the empty table or partition. If a subsequent
statement in the transaction is modifying the initially empty table again,
we must enable row-level undo logging, so that we will be able to
roll back to the start of the statement in case of an error (such as
duplicate key).
INSERT IGNORE will continue to use row-level logging and locking, because
implementing it would require the ability to roll back the latest row.
Since the undo log that we write only allows us to roll back the entire
statement, we cannot support INSERT IGNORE. We will introduce a
handler::extra() parameter HA_EXTRA_IGNORE_INSERT to indicate to storage
engines that INSERT IGNORE is being executed.
In many test cases, we add an extra record to the table, so that during
the 'interesting' part of the test, row-level locking and logging will
be used.
Replicas will continue to use row-level logging and locking until
MDEV-24622 has been addressed. Likewise, this optimization will be
disabled in Galera cluster until MDEV-24623 enables it.
dict_table_t::bulk_trx_id: The latest active or committed transaction
that initiated an insert into an empty table or partition.
Protected by exclusive table lock and a clustered index leaf page latch.
ins_node_t::bulk_insert: Whether bulk insert was initiated.
trx_t::mod_tables: Use C++11 style accessors (emplace instead of insert).
Unlike earlier, this collection will cover also temporary tables.
trx_mod_table_time_t: Add start_bulk_insert(), end_bulk_insert(),
is_bulk_insert(), was_bulk_insert().
trx_undo_report_row_operation(): Before accessing any undo log pages,
invoke trx->mod_tables.emplace() in order to determine whether undo
logging was disabled, or whether this is the first INSERT and we are
supposed to write a TRX_UNDO_EMPTY record.
row_ins_clust_index_entry_low(): If we are inserting into an empty
clustered index leaf page, set the ins_node_t::bulk_insert flag for
the subsequent trx_undo_report_row_operation() call.
lock_rec_insert_check_and_lock(), lock_prdt_insert_check_and_lock():
Remove the redundant parameter 'flags' that can be checked in the caller.
btr_cur_ins_lock_and_undo(): Simplify the logic. Correctly write
DB_TRX_ID,DB_ROLL_PTR after invoking trx_undo_report_row_operation().
trx_mark_sql_stat_end(), ha_innobase::extra(HA_EXTRA_IGNORE_INSERT),
ha_innobase::external_lock(): Invoke trx_t::end_bulk_insert() so that
the next statement will not be covered by table-level undo logging.
ReadView::changes_visible(trx_id_t) const: New accessor for the case
where the trx_id_t is not read from a potentially corrupted index page
but directly from the memory. In this case, we can skip a sanity check.
row_sel(), row_sel_try_search_shortcut(), row_search_mvcc():
row_sel_try_search_shortcut_for_mysql(),
row_merge_read_clustered_index(): Check dict_table_t::bulk_trx_id.
row_sel_clust_sees(): Replaces lock_clust_rec_cons_read_sees().
lock_sec_rec_cons_read_sees(): Replaced with lower-level code.
btr_root_page_init(): Refactored from btr_create().
dict_index_t::clear(), dict_table_t::clear(): Empty an index or table,
for the ROLLBACK of an INSERT operation.
ROW_T_EMPTY, ROW_OP_EMPTY: Note a concurrent ROLLBACK of an INSERT
into an empty table.
This is joint work with Thirunarayanan Balathandayuthapani,
who created a working prototype.
Thanks to Matthias Leich for extensive testing.
Remove usage of deprecated variable storage_engine. It was deprecated in 5.5 but
it never issued a deprecation warning. Make it issue a warning in 10.5.1.
Replaced with default_storage_engine.
storage/innobase/handler/handler0alter.cc:
for NEWDATE key_type says unsigned, thus col->prtype says unsigned,
but field->flags says signed. Use the same flag for value retrieval
that was used for value storage.
