After-review changes.
For this patch in 10.0, we do not introduce a new public storage engine API,
we just fix the InnoDB/XtraDB issues. In 10.1, we will make a better public
API that can be used for all storage engines (MDEV-6429).
Eliminate the background thread that did deadlock kills asynchroneously.
Instead, we ensure that the InnoDB/XtraDB code can handle doing the kill from
inside the deadlock detection code (when thd_report_wait_for() needs to kill a
later thread to resolve a deadlock).
(We preserve the part of the original patch that introduces dedicated mutex
and condition for the slave init thread, to remove the abuse of
LOCK_thread_count for start/stop synchronisation of the slave init thread).
replication causing replication to fail.
Remove the temporary fix for MDEV-5914, which used READ COMMITTED for parallel
replication worker threads. Replace it with a better, more selective solution.
The issue is with certain edge cases of InnoDB gap locks, for example between
INSERT and ranged DELETE. It is possible for the gap lock set by the DELETE to
block the INSERT, if the DELETE runs first, while the record lock set by
INSERT does not block the DELETE, if the INSERT runs first. This can cause a
conflict between the two in parallel replication on the slave even though they
ran without conflicts on the master.
With this patch, InnoDB will ask the server layer about the two involved
transactions before blocking on a gap lock. If the server layer tells InnoDB
that the transactions are already fixed wrt. commit order, as they are in
parallel replication, InnoDB will ignore the gap lock and allow the two
transactions to proceed in parallel, avoiding the conflict.
Improve the fix for MDEV-6020. When InnoDB itself detects a deadlock, it now
asks the server layer for any preferences about which transaction to roll
back. In case of parallel replication with two transactions T1 and T2 fixed to
commit T1 before T2, the server layer will ask InnoDB to roll back T2 as the
deadlock victim, not T1. This helps in some cases to avoid excessive deadlock
rollback, as T2 will in any case need to wait for T1 to complete before it can
itself commit.
Also some misc. fixes found during development and testing:
- Remove thd_rpl_is_parallel(), it is not used or needed.
- Use KILL_CONNECTION instead of KILL_QUERY when a parallel replication
worker thread is killed to resolve a deadlock with fixed commit
ordering. There are some cases, eg. in sql/sql_parse.cc, where a KILL_QUERY
can be ignored if the query otherwise completed successfully, and this
could cause the deadlock kill to be lost, so that the deadlock was not
correctly resolved.
- Fix random test failure due to missing wait_for_binlog_checkpoint.inc.
- Make sure that deadlock or other temporary errors during parallel
replication are not printed to the the error log; there were some places
around the replication code with extra error logging. These conditions can
occur occasionally and are handled automatically without breaking
replication, so they should not pollute the error log.
- Fix handling of rgi->gtid_sub_id. We need to be able to access this also at
the end of a transaction, to be able to detect and resolve deadlocks due to
commit ordering. But this value was also used as a flag to mark whether
record_gtid() had been called, by being set to zero, losing the value. Now,
introduce a separate flag rgi->gtid_pending, so rgi->gtid_sub_id remains
valid for the entire duration of the transaction.
- Fix one place where the code to handle ignored errors called reset_killed()
unconditionally, even if no error was caught that should be ignored. This
could cause loss of a deadlock kill signal, breaking deadlock detection and
resolution.
- Fix a couple of missing mysql_reset_thd_for_next_command(). This could
cause a prior error condition to remain for the next event executed,
causing assertions about errors already being set and possibly giving
incorrect error handling for following event executions.
- Fix code that cleared thd->rgi_slave in the parallel replication worker
threads after each event execution; this caused the deadlock detection and
handling code to not be able to correctly process the associated
transactions as belonging to replication worker threads.
- Remove useless error code in slave_background_kill_request().
- Fix bug where wfc->wakeup_error was not cleared at
wait_for_commit::unregister_wait_for_prior_commit(). This could cause the
error condition to wrongly propagate to a later wait_for_prior_commit(),
causing spurious ER_PRIOR_COMMIT_FAILED errors.
- Do not put the binlog background thread into the processlist. It causes
too many result differences in mtr, but also it probably is not useful
for users to pollute the process list with a system thread that does not
really perform any user-visible tasks...
replication causing replication to fail.
In parallel replication, we run transactions from the master in parallel, but
force them to commit in the same order they did on the master. If we force T1
to commit before T2, but T2 holds eg. a row lock that is needed by T1, we get
a deadlock when T2 waits until T1 has committed.
Usually, we do not run T1 and T2 in parallel if there is a chance that they
can have conflicting locks like this, but there are certain edge cases where
it can occasionally happen (eg. MDEV-5914, MDEV-5941, MDEV-6020). The bug was
that this would cause replication to hang, eventually getting a lock timeout
and causing the slave to stop with error.
With this patch, InnoDB will report back to the upper layer whenever a
transactions T1 is about to do a lock wait on T2. If T1 and T2 are parallel
replication transactions, and T2 needs to commit later than T1, we can thus
detect the deadlock; we then kill T2, setting a flag that causes it to catch
the kill and convert it to a deadlock error; this error will then cause T2 to
roll back and release its locks (so that T1 can commit), and later T2 will be
re-tried and eventually also committed.
The kill happens asynchroneously in a slave background thread; this is
necessary, as the reporting from InnoDB about lock waits happen deep inside
the locking code, at a point where it is not possible to directly call
THD::awake() due to mutexes held.
Deadlock is assumed to be (very) rarely occuring, so this patch tries to
minimise the performance impact on the normal case where no deadlocks occur,
rather than optimise the handling of the occasional deadlock.
Also fix transaction retry due to deadlock when it happens after a transaction
already signalled to later transactions that it started to commit. In this
case we need to undo this signalling (and later redo it when we commit again
during retry), so following transactions will not start too early.
Also add a missing thd->send_kill_message() that got triggered during testing
(this corrects an incorrect fix for MySQL Bug#58933).
Analysis: In wsrep case there is two transactions possible trx and
conflicting lock owning transaction. Code was handling trx mutexin
correctly but not for c_lock->trx case.
Fixed by taking clock-trx mutex when needed and releasing trx
mutex if it is taken at lower levels.
Update InnoDB to 5.6.14
Apply MySQL-5.6 hack for MySQL Bug#16434374
Move Aria-only HA_RTREE_INDEX from my_base.h to maria_def.h (breaks an assert in InnoDB)
Fix InnoDB memory leak
IN LOCK_VALIDATE()
rb://917
approved by: Marko Makela
In lock_validate() the limit is used to release the kernel_mutex during
the validation, to obey the latching order.
If we do the limit++ then we are rechecking the same lock most times on
each iteration because limit is being incremented by one and
<space, page_no> will nearly always be > limit. If we set the limit
correctly to (space, page+1) then we are actually making progress
during the iteration.
print page dump
buf_page_print(): Remove the ut_ad(0) from the beginning. Add two flags
(enum buf_page_print_flags) that can be bitwise-ORed together:
BUF_PAGE_PRINT_NO_CRASH:
Do not crash debug builds at the end of buf_page_print().
BUF_PAGE_PRINT_NO_FULL:
Do not print the full page dump. This can be useful when adding
diagnostic printout to flushing or to the doublewrite buffer.
trx_sys_doublewrite_init_or_restore_page(): Replace exit(1) with ut_error,
so that we can get a core dump if this extraordinary condition happens.
rb:924 approved by Sunny Bains
This fix does not remove the underlying cause of the assertion
failure. It just works around the problem, allowing a corrupted
secondary index to be fixed by DROP INDEX and CREATE INDEX (or in the
worst case, by re-creating the table).
ibuf_delete(): If the record to be purged is the last one in the page
or it is not delete-marked, refuse to purge it. Instead, write an
error message to the error log and let a debug assertion fail.
ibuf_set_del_mark(): If the record to be delete-marked is not found,
display some more information in the error log and let a debug
assertion fail.
row_undo_mod_del_unmark_sec_and_undo_update(),
row_upd_sec_index_entry(): Let a debug assertion fail when the record
to be delete-marked is not found.
buf_page_print(): Add ut_ad(0) so that corruption will be more
prominent in stress testing with debug binaries. Add ut_ad(0) here and
there where corruption is noticed.
btr_corruption_report(): Display some data on page_is_comp() mismatch.
btr_assert_not_corrupted(): A wrapper around btr_corruption_report().
Assert that page_is_comp() agrees with the table flags.
rb:911 approved by Inaam Rana
Fix a deadlock in the initial patch. lock_validate() must not hold the
lock system mutex while s-latching a block, because some functions,
such as lock_rec_convert_impl_to_expl(), may be already holding an x-latch
on the block that lock_validate() is interested in while attempting to
acquire the lock system mutex.
This deadlock was not caught by UNIV_SYNC_DEBUG because of
buf_block_dbg_add_level(block, SYNC_NO_ORDER_CHECK).
lock_clust_rec_some_has_impl(), row_get_rec_trx_id(),
lock_rec_queue_validate(), lock_table_other_has_incompatible(),
lock_table_has_to_wait_in_queue(), lock_table_queue_validate():
Add const qualifiers.
row_get_trx_id_offset(): Add const qualifiers. Keep the parameter rec
only in UNIV_DEBUG builds. Inline the function.
lock_rec_validate_page(): Take the buffer block as a parameter, to
avoid a buf_page_get_gen() call in most cases.
lock_rec_validate_page_low(): A version of lock_rec_validate_page()
that assumes that the lock system mutexes are already being held.
lock_rec_get_next_on_page_const(): A const variant of
lock_rec_get_next_on_page().
lock_validate(): Do not release the lock system mutex while
buffer-fixing the block for the lock_rec_validate_page() call.
Releasing the mutex apparently caused the assertion failure.
rb:665 approved by Sunny Bains
It is filling the error log when testing the debug version of the server.
The printout only seems to be useful when debugging a crash, not when
testing an instrumented version of the server.
Fix compiler warning:
lock/lock0lock.c: In function 'lock_print_info_all_transactions':
lock/lock0lock.c:4299:10: error: variable 'page' set but not used [-Werror=unused-but-set-variable]
------------------------------------------------------------
revno: 3495
committer: Marko Mäkelä <marko.makela@oracle.com>
branch nick: 5.1-innodb
timestamp: Wed 2010-06-02 13:37:14 +0300
message:
Bug#53674: InnoDB: Error: unlock row could not find a 4 mode lock on the record
In semi-consistent read, only unlock freshly locked non-matching records.
lock_rec_lock_fast(): Return LOCK_REC_SUCCESS,
LOCK_REC_SUCCESS_CREATED, or LOCK_REC_FAIL instead of TRUE/FALSE.
enum db_err: Add DB_SUCCESS_LOCKED_REC for indicating a successful
operation where a record lock was created.
lock_sec_rec_read_check_and_lock(),
lock_clust_rec_read_check_and_lock(), lock_rec_enqueue_waiting(),
lock_rec_lock_slow(), lock_rec_lock(), row_ins_set_shared_rec_lock(),
row_ins_set_exclusive_rec_lock(), sel_set_rec_lock(),
row_sel_get_clust_rec_for_mysql(): Return DB_SUCCESS_LOCKED_REC if a
new record lock was created. Adjust callers.
row_unlock_for_mysql(): Correct the function documentation.
row_prebuilt_t::new_rec_locks: Correct the documentation.
In semi-consistent read, only unlock freshly locked non-matching records.
Define DB_SUCCESS_LOCKED_REC for indicating a successful operation
where a record lock was created.
lock_rec_lock_fast(): Return LOCK_REC_SUCCESS,
LOCK_REC_SUCCESS_CREATED, or LOCK_REC_FAIL instead of TRUE/FALSE.
lock_sec_rec_read_check_and_lock(),
lock_clust_rec_read_check_and_lock(), lock_rec_enqueue_waiting(),
lock_rec_lock_slow(), lock_rec_lock(), row_ins_set_shared_rec_lock(),
row_ins_set_exclusive_rec_lock(), sel_set_rec_lock(),
row_sel_get_clust_rec_for_mysql(): Return DB_SUCCESS_LOCKED_REC if a
new record lock was created. Adjust callers.
row_unlock_for_mysql(): Correct the function documentation.
row_prebuilt_t::new_rec_locks: Correct the documentation.
