If a prepared statement used both a MyISAMMRG table and a stored
function or trigger, execution could fail with "No such table"
error or crash.
The error would come from a failure of the MyISAMMRG engine
to meet the expectations of the prelocking algorithm,
in particular maintain lex->query_tables_own_last pointer
in sync with lex->query_tables_last pointer/the contents
of lex->query_tables. When adding merge children, the merge
engine would extend the table list. Then, when adding
prelocked tables, the prelocking algorithm would use a pointer
to the last merge child to assign to lex->query_tables_own_last.
Then, when merge children were removed at the end of
open_tables(), lex->query_tables_own_last
was not updated, and kept pointing
to a removed merge child.
The fix ensures that query_tables_own_last is always in
sync with lex->query_tables_last.
This is a regression introduced by WL#4144 and present only
in next-4284 tree and 6.0.
----------------------------------------------------------
revno: 2617.69.21
committer: Konstantin Osipov <kostja@sun.com>
branch nick: 5.4-4284-1-assert
timestamp: Thu 2009-08-13 20:13:55 +0400
message:
A fix and a test case for Bug#46610 "MySQL 5.4.4: MyISAM MRG engine crash
on auto-repair of child".
Also fixes Bug#42862 "Crash on failed attempt to open a children of a
merge table".
MERGE engine needs to extend the global table list
with TABLE_LIST elements for child tables,
so that they are opened and locked.
Previously these table list elements were allocated
in memory of ha_myisammrg object (MERGE engine handler).
That would lead to access to freed memory in
recover_from_failed_open_table_attempt(), which would
try to recover a MERGE table child (MyISAM table)
and use for that TABLE_LIST of that child.
But by the time recover_from_failed_open_table_attempt()
is invoked, ha_myisammrg object that owns this
TABLE_LIST may be destroyed, and thus TABLE_LIST
memory freed.
The fix is to ensure that TABLE_LIST elements
that are added to the global table list (lex->query_tables)
are always allocated in thd->mem_root, which is not
destroyed until end of execution.
If previously TABLE_LIST elements were allocated
at ha_myisammrg::open() (i.e. when the TABLE
object was created and added to the table cache),
now they are allocated in ha_myisammrg::add_chidlren_list()
(i.e. right after "open" of the merge parent in
open_tables()).
We still create a list of children names
at ha_myisammrg::open() to use as a basis
for creation of TABLE_LISTs, that allows
to avoid reading the merge handler data
file on every execution.
----------------------------------------------------------
revno: 2617.69.20
committer: Konstantin Osipov <kostja@sun.com>
branch nick: 5.4-4284-1-assert
timestamp: Thu 2009-08-13 18:29:55 +0400
message:
WL#4284 "Transactional DDL locking"
A review fix.
Since WL#4284 implementation separated MDL_request and MDL_ticket,
MDL_request becamse a utility object necessary only to get a ticket.
Store it by-value in TABLE_LIST with the intent to merge
MDL_request::key with table_list->table_name and table_list->db
in future.
Change the MDL subsystem to not require MDL_requests to
stay around till close_thread_tables().
Remove the list of requests from the MDL context.
Requests for shared metadata locks acquired in open_tables()
are only used as a list in recover_from_failed_open_table_attempt(),
which calls mdl_context.wait_for_locks() for this list.
To keep such list for recover_from_failed_open_table_attempt(),
introduce a context class (Open_table_context), that collects
all requests.
A lot of minor cleanups and simplications that became possible
with this change.
----------------------------------------------------------
revno: 2617.23.20
committer: Konstantin Osipov <kostja@sun.com>
branch nick: mysql-6.0-runtime
timestamp: Wed 2009-03-04 16:31:31 +0300
message:
WL#4284 "Transactional DDL locking"
Review comments: "Objectify" the MDL API.
MDL_request and MDL_context still need manual construction and
destruction, since they are used in environment that is averse
to constructors/destructors.
------------------------------------------------------------
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: 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"
Backport of:
------------------------------------------------------------
revno: 2630.4.1
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Fri 2008-05-23 17:54:03 +0400
message:
WL#3726 "DDL locking for all metadata objects".
After review fixes in progress.
------------------------------------------------------------
This is the first patch in series. It transforms the metadata
locking subsystem to use a dedicated module (mdl.h,cc). No
significant changes in the locking protocol.
The import passes the test suite with the exception of
deprecated/removed 6.0 features, and MERGE tables. The latter
are subject to a fix by WL#4144.
Unfortunately, the original changeset comments got lost in a merge,
thus this import has its own (largely insufficient) comments.
This patch fixes Bug#25144 "replication / binlog with view breaks".
Warning: this patch introduces an incompatible change:
Under LOCK TABLES, it's no longer possible to FLUSH a table that
was not locked for WRITE.
Under LOCK TABLES, it's no longer possible to DROP a table or
VIEW that was not locked for WRITE.
******
Backport of:
------------------------------------------------------------
revno: 2630.4.2
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sat 2008-05-24 14:03:45 +0400
message:
WL#3726 "DDL locking for all metadata objects".
After review fixes in progress.
******
Backport of:
------------------------------------------------------------
revno: 2630.4.3
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sat 2008-05-24 14:08:51 +0400
message:
WL#3726 "DDL locking for all metadata objects"
Fixed failing Windows builds by adding mdl.cc to the lists
of files needed to build server/libmysqld on Windows.
******
Backport of:
------------------------------------------------------------
revno: 2630.4.4
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sat 2008-05-24 21:57:58 +0400
message:
WL#3726 "DDL locking for all metadata objects".
Fix for assert failures in kill.test which occured when one
tried to kill ALTER TABLE statement on merge table while it
was waiting in wait_while_table_is_used() for other connections
to close this table.
These assert failures stemmed from the fact that cleanup code
in this case assumed that temporary table representing new
version of table was open with adding to THD::temporary_tables
list while code which were opening this temporary table wasn't
always fulfilling this.
This patch changes code that opens new version of table to
always do this linking in. It also streamlines cleanup process
for cases when error occurs while we have new version of table
open.
******
WL#3726 "DDL locking for all metadata objects"
Add libmysqld/mdl.cc to .bzrignore.
******
Backport of:
------------------------------------------------------------
revno: 2630.4.6
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sun 2008-05-25 00:33:22 +0400
message:
WL#3726 "DDL locking for all metadata objects".
Addition to the fix of assert failures in kill.test caused by
changes for this worklog.
Make sure we close the new table only once.
WL#3951 - MyISAM: Additional Error Logs for Data Corruption
When table corruption is detected, in addition to current error message
provide following information:
- list of threads (and queries) accessing a table;
- thread_id of a thread that detected corruption;
- source file name and line number where this corruption was detected;
- optional extra information (string).
----------------------------------------------------------------------
ChangeSet@1.2571, 2008-04-08 12:30:06+02:00, vvaintroub@wva. +122 -0
Bug#32082 : definition of VOID in my_global.h conflicts with Windows
SDK headers
VOID macro is now removed. Its usage is replaced with void cast.
In some cases, where cast does not make much sense (pthread_*, printf,
hash_delete, my_seek), cast is ommited.
2677 Vladislav Vaintroub 2008-11-04
CMakeLists.txt files cleanup
- remove SAFEMALLOC and SAFE_MUTEX definitions that were
present in *each* CMakeLists.txt. Instead, put them into top level
CMakeLists.txt, but disable on Windows, because
a) SAFEMALLOC does not add any functionality that is not already
present in Debug C runtime ( and 2 safe malloc one on top of the other
only unnecessarily slows down the server)
b)SAFE_MUTEX does not work on Windows and have been
explicitely disabled on Windows with #undef previously. Fortunately,
ntdll does pretty good job identifying l problems with
CRITICAL_SECTIONs.
DebugBreak()s on using uninited critical section, unlocking unowned
critical section)
-Also, remove occationally used -D_DEBUG (added by compiler
anyway)
bzr branch mysql-5.1-performance-version mysql-trunk # Summit
cd mysql-trunk
bzr merge mysql-5.1-innodb_plugin # which is 5.1 + Innodb plugin
bzr rm innobase # remove the builtin
Next step: build, test fixes.
A REPLACE in the MERGE engine is actually a REPLACE
into one (FIRST or LAST) of the underlying MyISAM
tables. So in effect the server works on the meta
data of the MERGE table, while the real insert happens
in the MyISAM table.
The MERGE table has no index, while MyISAM has a
unique index. When a REPLACE into a MERGE table (
and the REPLACE conflicts with a duplicate in a
child table) is done, we try to access the duplicate
key information for the MERGE table. This information
actually does not exist, hence this results in a crash.
The problem can be resolved by modifying the MERGE
engine to provide us the duplicate key information
directly, instead of just returning the MyISAM index
number as the error key. Then the SQL layer (or "the
server") does not try to access the key_info of the
MERGE table, which does not exist.
The current patch modifies the MERGE engine to provide
the position for a record where a unique key violation
occurs.
and base tables
myrg_attach_children() could reuse a buffer that was allocated
previously based on a definition of a child table. The problem
was that the child's definition might have been changed, so
reusing the buffer could lead to crashes or valgrind errors
under some circumstances.
Fixed by changing myrg_attach_children() so that the
rec_per_key_part buffer is reused only when the child table
have not changed, and reallocated otherwise (the old buffer is
deallocated if necessary).
The conformance checker was not taking into
account, and, making concessions for acceptable
incompatibilites in tables created by
versions earlier than 4.1.
The current patch relaxes the conformance
checker to ignore differences in key_alg
and language for tables created by versions
earlier than 4.1.
Probe definition file is now a separate file that is copied during
build to the correct location, this enforces dependency requirements
correctly and allows builds to work when using the current or separate
build directories
