----------------------------------------------------------
revno: 2617.69.2
committer: Konstantin Osipov <kostja@sun.com>
branch nick: 5.4-azalea-bugfixing
timestamp: Mon 2009-08-03 19:26:04 +0400
message:
A fix and a test case for Bug#45035 "Altering table under LOCK TABLES
results in "Error 1213 Deadlock found...".
If a user had a table locked with LOCK TABLES
for READ and for WRITE in the same connection, ALTER TABLE
could fail.
Root cause analysis:
If a connection issues
LOCK TABLE t1 write, t1 a read, t1 b read;
the new LOCK TABLES code in 6.0 (part of WL 3726) will create
the following list of TABLE_LIST objects
(thd->locked_tables_list->m_locked_tables):
{"t1" "b" tl_read_no_insert}, {"t1" "a" tl_read_no_insert},
{"t1" "t1" tl_write }
Later on, when we try to ALTER table t1, mysql_alter_table()
closes all TABLE instances and releases its thr_lock locks,
keeping only an exclusive metadata lock on t1.
But when ALTER is finished, Locked_table_list::reopen_tables()
tries to restore the original list of open and locked tables.
Before this patch, it used to do so one by one:
Open t1 b, get TL_READ_NO_INSERT lock,
Open t1 a, get TL_READ_NO_INSERT lock
Open t1, try to get TL_WRITE lock, deadlock.
The cause of the deadlock is that thr_lock.c doesn't
resolve the situation when the read list only consists
of locks taken by the same thread, followed by this very
thread trying to take a WRITE lock. Indeed, since
thr_lock_multi always gets a sorted list of locks,
WRITE locks always precede READ locks in the list
to lock.
Don't try to fix thr_lock.c deficiency, keep this
code simple.
Instead, try to take all thr_lock locks at once
in ::reopen_tables().
------------------------------------------------------------
revno: 2617.43.3
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 40188-6.0
timestamp: Thu 2009-05-07 13:15:54 +0200
message:
Sort results as the file list of the database directory is not
sorted (MY_DONT_SORT).
(This is a follow-up fix for WL#4284).
Part 2 :
There was a special optimization on the ref access method for
ORDER BY ... DESC that was set without actually looking on the type of the
selected index for ORDER BY.
Fixed the SELECT ... ORDER BY .. DESC (it uses a different code path compared
to the ASC that has been fixed with the previous fix).
The problem is not actually related to 2byte collation IDs.
The same crash happens if you change the collation ID in
mysql-test/str_data/Index.xml to a value smaller than 256.
Crash happened in SQL parser, because the "ident_map" and "state_map"
arrays were not initialized in loadable utf8 collations.
Fix: adding proper initialization of the "ident_map" and "state_map"
members for loadable utf8 collations.
{PROCEDURE|FUNCTION} FROM ...'
The master would hit an assertion when binary log was
active. This was due to the fact that the thread's diagnostics
area was being cleared before writing to the binlog,
independently of mysql_routine_grant returning an error or
not. When mysql_routine_grant was to return an error, the return
value and the diagnostics area contents would
mismatch. Consequently, neither my_ok would be called nor an
error would be signaled in the diagnostics area, eventually
triggering the assertion in net_end_statement.
We fix this by not clearing the diagnostics area at binlogging
time.
escaped field names
When in mixed or statement mode, the master logs LOAD DATA
queries by resorting to an Execute_load_query_log_event. This
event does not contain the original query, but a rewritten
version of it, which includes the table field names. However, the
rewrite does not escape the field names. If these names match a
reserved keyword, then the slave will stop with a syntax error
when executing the event.
We fix this by escaping the fields names as it happens already
for the table name.
2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1
- initial changeset that introduced the fix for
Bug#989 and follow up fixes for all test suite failures
introduced in the initial changeset.
------------------------------------------------------------
revno: 2617.31.1
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Fri 2009-03-06 19:17:00 -0300
message:
Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order
WL#4284: Transactional DDL locking
Currently the MySQL server does not keep metadata locks on
schema objects for the duration of a transaction, thus failing
to guarantee the integrity of the schema objects being used
during the transaction and to protect then from concurrent
DDL operations. This also poses a problem for replication as
a DDL operation might be replicated even thought there are
active transactions using the object being modified.
The solution is to defer the release of metadata locks until
a active transaction is either committed or rolled back. This
prevents other statements from modifying the table for the
entire duration of the transaction. This provides commitment
ordering for guaranteeing serializability across multiple
transactions.
- Incompatible change:
If MySQL's metadata locking system encounters a lock conflict,
the usual schema is to use the try and back-off technique to
avoid deadlocks -- this schema consists in releasing all locks
and trying to acquire them all in one go.
But in a transactional context this algorithm can't be utilized
as its not possible to release locks acquired during the course
of the transaction without breaking the transaction commitments.
To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be
returned if a lock conflict is encountered during a transaction.
Let's consider an example:
A transaction has two statements that modify table t1, then table
t2, and then commits. The first statement of the transaction will
acquire a shared metadata lock on table t1, and it will be kept
utill COMMIT to ensure serializability.
At the moment when the second statement attempts to acquire a
shared metadata lock on t2, a concurrent ALTER or DROP statement
might have locked t2 exclusively. The prescription of the current
locking protocol is that the acquirer of the shared lock backs off
-- gives up all his current locks and retries. This implies that
the entire multi-statement transaction has to be rolled back.
- Incompatible change:
FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ
LOCK won't cause locked tables to be implicitly unlocked anymore.
field='const1' AND field='const2' in some cases
Building multiple equality predicates containing
a constant which is compared as a datetime (with a field)
we should take this fact into account and compare the
constant with another possible constatns as datetimes
as well.
E.g. for the
SELECT ... WHERE a='2001-01-01' AND a='2001-01-01 00:00:00'
we should compare '2001-01-01' with '2001-01-01 00:00:00' as
datetimes but not as strings.
The problem was that the multiple evaluations of a ENCODE or
DECODE function within a single statement caused the random
generator to be reinitialized at each evaluation, even though
the parameters were constants.
The solution is to initialize the random generator only once
if the password (seed) parameter is constant.
This patch borrows code and ideas from Georgi Kodinov's patch.
This patch fixes three bugs as follows. First, aborting the server while purging
binary logs might generate orphan files due to how the purge operation was
implemented:
(purge routine - sql/log.cc - MYSQL_BIN_LOG::purge_logs)
1 - register the files to be removed in a temporary buffer.
2 - update the log-bin.index.
3 - flush the log-bin.index.
4 - erase the files whose names where register in the temporary buffer
in step 1.
Thus a failure while executing step 4 would generate an orphan file. Second,
a similar issue might happen while creating a new binary as follows:
(create routine - sql/log.cc - MYSQL_BIN_LOG::open)
1 - open the new log-bin.
2 - update the log-bin.index.
Thus a failure while executing step 1 would generate an orphan file.
To fix these issues, we record the files to be purged or created before really
removing or adding them. So if a failure happens such records can be used to
automatically remove dangling files. The new steps might be outlined as follows:
(purge routine - sql/log.cc - MYSQL_BIN_LOG::purge_logs)
1 - register the files to be removed in the log-bin.~rec~ placed in
the data directory.
2 - update the log-bin.index.
3 - flush the log-bin.index.
4 - delete the log-bin.~rec~.
(create routine - sql/log.cc - MYSQL_BIN_LOG::open)
1 - register the file to be created in the log-bin.~rec~
placed in the data directory.
2 - open the new log-bin.
3 - update the log-bin.index.
4 - delete the log-bin.~rec~.
(recovery routine - sql/log.cc - MYSQL_BIN_LOG::open_index_file)
1 - open the log-bin.index.
2 - open the log-bin.~rec~.
3 - for each file in log-bin.~rec~.
3.1 Check if the file is in the log-bin.index and if so ignore it.
3.2 Otherwise, delete it.
The third issue can be described as follows. The purge operation was allowing
to remove a file in use thus leading to the loss of data and possible
inconsistencies between the master and slave. Roughly, the routine was only
taking into account the dump threads and so if a slave was not connect the
file might be delete even though it was in use.
Before this patch, semisync assumed transactions running in parallel
can not be larger than max_connections, but this is not true when
the event scheduler is executing events, and cause semisync run out
of preallocated transaction nodes.
Fix the problem by allocating transaction nodes dynamically.
This patch also fixed a possible deadlock when running UNINSTALL
PLUGIN rpl_semi_sync_master and updating in parallel. Fixed by
releasing the internal Delegate lock before unlock the plugins.
------------------------------------------------------------
revno: 2617.23.18
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Mon 2009-03-02 18:18:26 -0300
message:
Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order
WL#4284: Transactional DDL locking
This is a prerequisite patch:
These changes are intended to split lock requests from granted
locks and to allow the memory and lifetime of granted locks to
be managed within the MDL subsystem. Furthermore, tickets can
now be shared and therefore are used to satisfy multiple lock
requests, but only shared locks can be recursive.
The problem is that the MDL subsystem morphs lock requests into
granted locks locks but does not manage the memory and lifetime
of lock requests, and hence, does not manage the memory of
granted locks either. This can be problematic because it puts the
burden of tracking references on the users of the subsystem and
it can't be easily done in transactional contexts where the locks
have to be kept around for the duration of a transaction.
Another issue is that recursive locks (when the context trying to
acquire a lock already holds a lock on the same object) requires
that each time the lock is granted, a unique lock request/granted
lock structure structure must be kept around until the lock is
released. This can lead to memory leaks in transactional contexts
as locks taken during the transaction should only be released at
the end of the transaction. This also leads to unnecessary wake
ups (broadcasts) in the MDL subsystem if the context still holds
a equivalent of the lock being released.
These issues are exacerbated due to the fact that WL#4284 low-level
design says that the implementation should "2) Store metadata locks
in transaction memory root, rather than statement memory root" but
this is not possible because a memory root, as implemented in mysys,
requires all objects allocated from it to be freed all at once.
This patch combines review input and significant code contributions
from Konstantin Osipov (kostja) and Dmitri Lenev (dlenev).
------------------------------------------------------------
revno: 3035.4.1
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 39897-6.0
timestamp: Thu 2009-01-15 12:17:57 -0200
message:
Bug#39897: lock_multi fails in pushbuild: timeout waiting for processlist
The problem is that relying on the "Table lock" thread state in
its current position to detect that a thread is waiting on a lock
is race prone. The "Table lock" state change happens before the
thread actually tries to grab a lock on a table.
The solution is to move the "Table lock" state so that its set
only when a thread is actually going to wait for a lock. The state
change happens after the thread fails to grab the lock (because it
is owned by other thread) and proceeds to wait on a condition.
This is considered part of work related to WL#4284 "Transactional
DDL locking"
Warning: this patch contains an incompatible change.
When waiting on a lock in thr_lock.c, the server used to display "Locked"
processlist state. After this patch, the state is "Table lock".
The new state was actually intended to be display since year 2002,
when Monty added it. But up until removal of thd->locked boolean
member, this state was ignored by SHOW PROCESSLIST code.
"mysql_upgrade (ver 5.1) add 3 fields to mysql.proc table but does
not set values".
mysql_upgrade (ver 5.1) adds 3 fields (character_set_client,
collation_connection and db_collation) to the mysql.proc table, but
does not set any values. When we run stored procedures, which were
created with mysql 5.0, a warning is logged into the error log.
The solution to this is for mysql_upgrade to set default best guess
values for these fields. A warning is also written during upgrade, to
make the user aware that default values are set.
------------------------------------------------------------
revno: 2630.13.17
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Sun 2008-07-27 10:14:46 -0300
message:
Post-merge fixes:
Remove dependency on binlog, require not embedded as test uses
the event scheduler and disable abort on error for syntax only
available on servers built with debugging support.
This is a patch in scope of WL#4284 "Transactional DDL locking"
------------------------------------------------------------
revno: 2630.13.16
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: WL#4284
timestamp: Sat 2008-07-26 13:38:20 -0300
message:
WL#4284: Transactional DDL locking
SQL statements' effect on transactions.
Currently the MySQL server and its storage engines are not
capable of rolling back operations that define or modify data
structures (also known as DDL statements) or operations that
alter any of the system tables (the mysql database). Allowing
these group of statements to participate in transactions
is unfeasible at this time (since rollback has no effect
whatsoever on them) and goes against the design of our metadata
locking subsystem.
The solution is to issue implicit commits before and after
those statements execution. This effectively confines each of
those statements to its own special transaction and ensures
that metadata locks taken during this special transaction
are not leaked into posterior statements/transactions.
When checking for an error after removing the special view error handler the code
was not taking into account that open_tables() may fail because of the current
statement being killed.
Added a check for thd->killed.
Added a client program to test it.
When a .CSV file for table in the CSV engine contains
\X characters as part of unquoted fields, e.g.
2,naraya\nan
\n is not interpreted as a new line (it is however interpreted as a
newline in a quoted field).
The old algorithm copied the entire value for a unquoted field without
parsing the \X characters.
The new algorithm adds the capability to handle \X characters in the
unquoted fields of a .CSV file.
Problem: Item_char_typecast reported wrong max_length when
casting to BINARY, which lead, in particular, in wrong
"ORDER BY BINARY(char_column)" results.
Fix: making Item_char_typecast report correct max_length.
@ mysql-test/r/ctype_utf16.result
Fixing old incorrect test result.
@ mysql-test/r/ctype_utf32.result
Fixing old incorrect test result.
@ mysql-test/r/ctype_utf8.result
Adding new test
@ mysql-test/t/ctype_utf8.test
Adding new test
@ sql/item_timefunc.cc
Making Item_char_typecast report correct max_length
when cast is done to BINARY.
Support for flushing individual logs, so that the user can
selectively flush a subset of the server logs.
Flush of individual logs is done according to the
following syntax:
FLUSH <log_category> LOGS;
The syntax is extended so that the user is able to flush a
subset of logs:
FLUSH [log_category LOGS,];
where log_category is one of:
SLOW
ERROR
BINARY
ENGINE
GENERAL
RELAY.
----------------------------------------------------------
revno: 2630.4.38
committer: Konstantin Osipov <konstantin@mysql.com>
branch nick: mysql-6.0-4144
timestamp: Wed 2008-06-25 22:07:06 +0400
message:
WL#4144 - Lock MERGE engine children.
Committing a version of the patch merged with WL#3726
on behalf of Ingo.
Step #1: Move locking from parent to children.
MERGE children are now left in the query list of tables
after inserted there in open_tables(). So they are locked
by lock_tables() as all other tables are.
The MERGE parent does not store locks any more. It appears
in a MYSQL_LOCK with zero lock data. This is kind of a "dummy"
lock.
All other lock handling is also done directly on the children.
To protect against parent or child modifications during LOCK
TABLES, the children are detached after every statement and
attached before every statement, even under LOCK TABLES.
The children table list is removed from the query list of tables
on every detach and on close of the parent.
Step #2: Move MERGE specific functionality from SQL layer
into table handler.
Functionality moved from SQL layer (mainly sql_base.cc)
to the table handler (ha_myisammrg.cc).
Unnecessary code is removed from the SQL layer.
Step #3: Moved all MERGE specific members from TABLE
to ha_myisammrg.
Moved members from TABLE to ha_myisammrg.
Renamed some mebers.
Fixed comments.
Step #4: Valgrind and coverage testing
Valgrind did not uncover new problems.
Added purecov comments.
Added a new test for DATA/INDEX DIRECTORY options.
Changed handling of ::reset() for non-attached children.
Fixed the merge-big test.
Step #5: Fixed crashes detected during review
Changed detection when to attach/detach.
Added new tests.
Backport also the fix for Bug#44040 "MySQL allows creating a
MERGE table upon VIEWs but crashes when using it"
----------------------------------------------------------
revno: 2630.4.35
committer: Konstantin Osipov <konstantin@mysql.com>
branch nick: mysql-6.0-3726
timestamp: Wed 2008-06-25 16:44:00 +0400
message:
Fix a MyISAM-specific bug in the new implementation of
LOCK TABLES (WL#3726).
If more than one instance of a MyISAM table are open in the
same connection, all of them must share the same status_param.
Otherwise, unlock of a table may lead to lost records.
See also comments in thr_lock.c.
