m_tickets.front() == m_trans_sentinel'".
Debug build of server crashed due to assert failure in MDL
subsystem when one tried to execute multi-table REPAIR or
OPTIMIZE in autocommit=0 mode.
The assert failure occured when multi-table REPAIR or OPTIMIZE
started processing of second table from its table list and
tried to acquire upgradable metadata lock on this table.
The cause of the assert failure were MDL locks left over from
processing of previous table. It turned out that in autocommit=0
mode close_thread_tables() which happens at the end of table
processing doesn't release metadata locks.
This fix solves problem by releasing locks explicitly using
MDL_context::release_trans_locks() call.
fulltext search and row op.
The search for fulltext indexes is searching for some special
predicate layouts. While doing so it's not checking for the number
of columns of the expressions it tries to calculate.
And since row expressions can't return a single scalar value there
was a crash.
Fixed by checking if the expressions are scalar (in addition to
being constant) before calling Item::val_xxx() methods.
Fix Bug#50555 "handler commands crash server in my_hash_first()"
as a post-merge fix (the new handler tests are not passing
otherwise).
- in hash.c, don't call calc_hash if ! my_hash_inited().
- add tests and results for the test case for Bug#50555
Performing fulltext prefix search (a word with truncation
operator) may cause a dead-loop. ft_min_word_len value
doesn't matter actually.
The problem was introduced along with "smarter index merge"
optimization.
There was two problems:
The first was the symptom, caused by bad error handling in
ha_partition. It did not handle print_error etc. when
having no partitions (when used by dummy handler).
The second was the real problem that when dropping tables
it reused the table type (storage engine) from when the lock
was asked for, not the table type that it had when gaining
the exclusive name lock. So that it tried to delete tables
from wrong storage engines.
Solutions for the first problem was to accept some handler
calls to the partitioning handler even if it was not setup
with any partitions, and also if possible fallback
to use the base handler's default functions.
Solution for the second problem was to remove the optimization
to reuse the definition from the cache, instead always check
the frm-file when holding the LOCK_open mutex
(updated with a fix for a debug print crash and better
comments as required by reviewer, and removed optimization
to avoid reading the frm-file).
Add a wait-for graph based deadlock detector to the
MDL subsystem.
Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and
bug #37346 "innodb does not detect deadlock between update and
alter table".
The first bug manifested itself as an unwarranted abort of a
transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER
statement, when this transaction tried to repeat use of a
table, which it has already used in a similar fashion before
ALTER started.
The second bug showed up as a deadlock between table-level
locks and InnoDB row locks, which was "detected" only after
innodb_lock_wait_timeout timeout.
A transaction would start using the table and modify a few
rows.
Then ALTER TABLE would come in, and start copying rows
into a temporary table. Eventually it would stumble on
the modified records and get blocked on a row lock.
The first transaction would try to do more updates, and get
blocked on thr_lock.c lock.
This situation of circular wait would only get resolved
by a timeout.
Both these bugs stemmed from inadequate solutions to the
problem of deadlocks occurring between different
locking subsystems.
In the first case we tried to avoid deadlocks between metadata
locking and table-level locking subsystems, when upgrading shared
metadata lock to exclusive one.
Transactions holding the shared lock on the table and waiting for
some table-level lock used to be aborted too aggressively.
We also allowed ALTER TABLE to start in presence of transactions
that modify the subject table. ALTER TABLE acquires
TL_WRITE_ALLOW_READ lock at start, and that block all writes
against the table (naturally, we don't want any writes to be lost
when switching the old and the new table). TL_WRITE_ALLOW_READ
lock, in turn, would block the started transaction on thr_lock.c
lock, should they do more updates. This, again, lead to the need
to abort such transactions.
The second bug occurred simply because we didn't have any
mechanism to detect deadlocks between the table-level locks
in thr_lock.c and row-level locks in InnoDB, other than
innodb_lock_wait_timeout.
This patch solves both these problems by moving lock conflicts
which are causing these deadlocks into the metadata locking
subsystem, thus making it possible to avoid or detect such
deadlocks inside MDL.
To do this we introduce new type-of-operation-aware metadata
locks, which allow MDL subsystem to know not only the fact that
transaction has used or is going to use some object but also what
kind of operation it has carried out or going to carry out on the
object.
This, along with the addition of a special kind of upgradable
metadata lock, allows ALTER TABLE to wait until all
transactions which has updated the table to go away.
This solves the second issue.
Another special type of upgradable metadata lock is acquired
by LOCK TABLE WRITE. This second lock type allows to solve the
first issue, since abortion of table-level locks in event of
DDL under LOCK TABLES becomes also unnecessary.
Below follows the list of incompatible changes introduced by
this patch:
- From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those
statements that acquire TL_WRITE_ALLOW_READ lock)
wait for all transactions which has *updated* the table to
complete.
- From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE
(i.e. all statements which acquire TL_WRITE table-level lock) wait
for all transaction which *updated or read* from the table
to complete.
As a consequence, innodb_table_locks=0 option no longer applies
to LOCK TABLES ... WRITE.
- DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort
statements or transactions which use tables being dropped or
renamed, and instead wait for these transactions to complete.
- Since LOCK TABLES WRITE now takes a special metadata lock,
not compatible with with reads or writes against the subject table
and transaction-wide, thr_lock.c deadlock avoidance algorithm
that used to ensure absence of deadlocks between LOCK TABLES
WRITE and other statements is no longer sufficient, even for
MyISAM. The wait-for graph based deadlock detector of MDL
subsystem may sometimes be necessary and is involved. This may
lead to ER_LOCK_DEADLOCK error produced for multi-statement
transactions even if these only use MyISAM:
session 1: session 2:
begin;
update t1 ... lock table t2 write, t1 write;
-- gets a lock on t2, blocks on t1
update t2 ...
(ER_LOCK_DEADLOCK)
- Finally, support of LOW_PRIORITY option for LOCK TABLES ... WRITE
was abandoned.
LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same
priority as the usual LOCK TABLE ... WRITE.
SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE in
the wait queue.
- We do not take upgradable metadata locks on implicitly
locked tables. So if one has, say, a view v1 that uses
table t1, and issues:
LOCK TABLE v1 WRITE;
FLUSH TABLE t1; -- (or just 'FLUSH TABLES'),
an error is produced.
In order to be able to perform DDL on a table under LOCK TABLES,
the table must be locked explicitly in the LOCK TABLES list.
Fixed 2 problems :
1. test_if_order_by_key() was continuing on the primary key
as if it has a primary key suffix (as the secondary keys do).
This leads to crashes in ORDER BY <pk>,<pk>.
Fixed by not treating the primary key as the secondary one
and not depending on it being clustered with a primary key.
2. The cost calculation was trying to read the records
per key when operating on ORDER BYs that order on all of the
secondary key + some of the primary key.
This leads to crashes because of out-of-bounds array access.
Fixed by assuming we'll find 1 record per key in such cases.
column is used for ORDER BY
Problem: filesort isn't meant for null length sort data
(e.g. char(0)), that leads to a server crash.
Fix: disregard sort order if sort data record length is 0 (nothing
to sort).
The problem was that a DROP TRIGGER statement inside a stored
procedure could cause a crash in subsequent invocations. This
was due to the addition, on the first execution, of a temporary
table reference to the stored procedure query table list. In
a subsequent invocation, there would be a attempt to reinitialize
the temporary table reference, which by then was already gone.
The solution is to backup and reset the query table list each
time a trigger needs to be dropped. This ensures that any temp
changes to the query table list are discarded. It is safe to
do so at this time as drop trigger is restricted from more
complicated scenarios (ie, not allowed within stored functions,
etc).
Server crashes when accessing ARCHIVE table with missing
.ARZ file.
When opening a table, ARCHIVE didn't properly pass through
error code from lower level azopen() to higher level open()
method.
Bulk REPLACE or bulk INSERT ... ON DUPLICATE KEY UPDATE may
break dynamic record MyISAM table.
The problem is limited to bulk REPLACE and INSERT ... ON
DUPLICATE KEY UPDATE, because only these operations may
be done via UPDATE internally and may request write cache.
When flushing write cache, MyISAM may write remaining
cached data at wrong position. Fixed by requesting write
cache to seek to a correct position.
table and view...
Invalid memory reads after a query referencing MyISAM table
multiple times with write lock. Invalid memory reads may
lead to server crash, valgrind warnings, incorrect values
in INFORMATION_SCHEMA.TABLES.{TABLE_ROWS, DATA_LENGTH,
INDEX_LENGTH, ...}.
This may happen when one of the table instances gets closed
after a query, e.g. out of slots in open tables cache. UNION,
MERGE and VIEW are irrelevant.
The problem was that MyISAM didn't restore state info
pointer to default value.
In case of 'CREATE VIEW' subselect transformation does not happen(see JOIN::prepare).
During fix_fields Item_row may call is_null() method for its arugmens which
leads to item calculation(wrong subselect in our case as
transformation did not happen before). This is_null() call
does not make sence for 'CREATE VIEW'.
Note:
Only Item_row is affected because other items don't call is_null()
during fix_fields() for arguments.
SHOW CREATE TABLE on a view (v1) that contains a function whose
statement uses another view (v2), could trigger a infinite loop
if the view referenced within the function causes a warning to
be raised while opening the said view (v2).
The problem was a infinite loop over the stack of internal error
handlers. The problem would be triggered if the stack contained
two or more handlers and the first two handlers didn't handle the
raised condition. In this case, the loop variable would always
point to the second handler in the stack.
The solution is to correct the loop variable assignment so that
the loop is able to iterate over all handlers in the stack.
in multitable delete/subquery
SQL_BUFFER_RESULT should not have an effect on non-SELECT
statements according to our documentation.
Fixed by not passing it through to multi-table DELETE (similarly
to how it's done for multi-table UPDATE).
The problem was that a failure to open a view wasn't being
properly handled. When opening a view with unknown definer,
the open procedure would be treated as successful and would
later crash when attempting to lock the view (which wasn't
opened to begin with).
The solution is to skip further processing when opening a
table if it fails with a fatal error.
error causes debug assertion
The IGNORE option of the multiple-table UPDATE command was
not intended to suppress errors caused by the
sql_safe_updates mode. This flag will raise an error if the
execution of UPDATE does not use a key for row retrieval,
and should continue do so regardless of the IGNORE option.
However the implementation of IGNORE does not support
exceptions to the rule; it always converts errors to
warnings and cannot be extended. The Internal_error_handler
interface offers the infrastructure to handle individual
errors, making sure that the error raised by
sql_safe_updates is not silenced.
Fixed by implementing an Internal_error_handler and using it
for UPDATE IGNORE commands.
Detailed revision comments:
r6489 | sunny | 2010-01-21 02:57:50 +0200 (Thu, 21 Jan 2010) | 2 lines
branches/5.1: Factor out test for bug#44030 from innodb-autoinc.test
into a separate test/result files.
Detailed revision comments:
r6488 | sunny | 2010-01-21 02:55:08 +0200 (Thu, 21 Jan 2010) | 2 lines
branches/5.1: Factor out test for bug#44030 from innodb-autoinc.test
into a separate test/result files.
