insert...select
Queries following bulk insert into an empty MyISAM table
may break it. This was pure MyISAM problem.
When bulk insert into an empty table is complete, MyISAM
may want to enable indexes via repair by sort. If repair
by sort fails (e.g. insufficient buffer), MyISAM failover
to repair with key cache, requesting repair of data file.
Repair of data file performs data file substitution. This
means that current table instance will point to new data
file. Other cached table instances are still pointing to
an old, deleted data file.
This is fixed by not requesting repair of data file
during enable indexes.
Explicit REPAIR is not affected, since it flushes all
table instances.
BUG#47073 - valgrind errs, corruption,failed repair of partition,
low myisam_sort_buffer_size
Fixed race conditions discovered with the provided test case and
stabilized test case.
Implemented the server infrastructure for the fix:
1. Added a function LEX_STRING *thd_query_string(THD) to return
a LEX_STRING structure instead of char *.
This is the function that must be called in innodb instead of
thd_query()
2. Did some encapsulation in THD : aggregated thd_query and
thd_query_length into a LEX_STRING and made accessor and mutator
methods for easy code updating.
3. Updated the server code to use the new methods where applicable.
low myisam_sort_buffer_size
Repair by sort (default) or parallel repair of a MyISAM table
(doesn't matter partitioned or not) as well as bulk inserts
and enable indexes some times didn't failover to repair with
key cache.
The problem was that after unsuccessful attempt, data file was
closed. Whereas repair with key cache requires open data file.
Fixed by reopening data file.
Also fixed a valgrind warning, which may appear during repair
by sort or parallel repair with certain myisam_sort_buffer_size
number of rows and length of an index entry (very dependent).
the auto_increment value
This is an alternative patch that instead of allowing RECREATE TABLE
on TRUNCATE TABLE it implements reset_auto_increment that is called
after delete_all_rows.
Note: this bug was fixed by Mattias Jonsson:
Pusing this patch: http://lists.mysql.com/commits/70370
This patch fixes compilation warning, "conversion from 'time_t' to 'ulong',
possible loss of data".
The fix is to typecast time_t to ulong before assigning it to ulong.
Backported this from 6.0-bugteam tree.
This patch adds corrections to the original patch
submitted 2009-04-08 (http://lists.mysql.com/commits/71607):
- fixed that the original patch didn't work because of an
incorrect condition;
- added a test case.
Killing insert-select statement on MyISAM corrupts the table.
Killing the insert-select statement corrupts the MyISAM table only
when the destination table is empty and when it has indexes. When
we bulk insert huge data and if the destination table is empty we
disable the indexes for fast inserts, data is then inserted and
indexes are re-enabled after bulk_insert operation
Killing the query, aborts the repair table operation during enable
indexes phase leading to table corruption.
We now truncate the table when we detect that enable indexes is
killed for bulk insert query.As we have an empty table before the
operation, we can fix by truncating the table.
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.
The problem is that select queries executed concurrently with
a concurrent insert on a MyISAM table could be cached if the
select started after the query cache invalidation but before
the unlock of tables performed by the concurrent insert. This
race could happen because the concurrent insert was failing
to prevent cache of select queries happening at the same time.
The solution is to add a 'uncacheable' status flag to signal
that a concurrent insert is being performed on the table and
that queries executing at the same time shouldn't cache the
results.
- Remove bothersome warning messages. This change focuses on the warnings
that are covered by the ignore file: support-files/compiler_warnings.supp.
- Strings are guaranteed to be max uint in length
MyISAM did copy of key statistics incorrectly, which may cause
server crash or incorrect cardinality values. This may happen only on
platforms where size of long differs from size of pointer.
To determine number of bytes to be copied from array of ulong,
MyISAM mistakenly used sizoef(pointer) instead of sizeof(ulong).
code backported from 6.0
per-file messages:
include/my_global.h
Remove SC_MAXWIDTH. This is unused and irrelevant nowadays.
include/my_sys.h
Remove errbuf declaration and unused definitions.
mysys/my_error.c
Remove errbuf definition and move and adjust ERRMSGSIZE.
mysys/my_init.c
Declare buffer on the stack and use my_snprintf.
mysys/safemalloc.c
Use size explicitly. It's more than enough for the message at hand.
sql/sql_error.cc
Use size explicitly. It's more than enough for the message at hand.
sql/sql_parse.cc
Declare buffer on the stack. Use my_snprintf as it will result in
less stack space being used than by a system provided sprintf --
this allows us to put the buffer on the stack without causing much
trouble. Also, the use of errbuff here was not thread-safe as the
function can be entered concurrently from multiple threads.
sql/sql_table.cc
Use MYSQL_ERRMSG_SIZE. Extra space is not needed as my_snprintf will
nul terminate strings.
storage/myisam/ha_myisam.cc
Use MYSQL_ERRMSG_SIZE.
sql/share/errmsg.txt
Error message truncation in test "innodb" in embedded mode
filename in the error message can safely take up to 210 symbols.
mmap is slower that caching indeed.
Here the problem is that mmap is used even if --myisam-use-mmap=OFF
solved by checking the flag in ha_myisam::extra() as it is called in
init_read_record()
per-file comments:
storage/myisam/ha_myisam.cc
Bug#40634 table scan temporary table is 4x slower due to mmap instead instead of caching
do nothing for HA_EXTRA_MMAP if no opt_myisam_use_mmap
A table with BLOB/TEXT prefix key part, created with version 4.1,
could not be opened by a 5.1 server.
The routine check at table open, if the frm file matches the MyISAM
table, was too picky regarding old and new implementation of such
keys.
Added relaxed check for blob prefix key part.
No test case. It requires to create a table in 4.1 and open it in
5.1.
myisamchk did always show Character set: latin1_swedish_ci (8),
regardless what DEFAULT CHARSET the table had.
When the server created a MyISAM table, it did not copy the
characterset number into the MyISAM create info structure.
Added assignment of charset number to MI_CREATE_INFO.
corrupts a MERGE table
Bug 26867 - LOCK TABLES + REPAIR + merge table result in
memory/cpu hogging
Bug 26377 - Deadlock with MERGE and FLUSH TABLE
Bug 25038 - Waiting TRUNCATE
Bug 25700 - merge base tables get corrupted by
optimize/analyze/repair table
Bug 30275 - Merge tables: flush tables or unlock tables
causes server to crash
Bug 19627 - temporary merge table locking
Bug 27660 - Falcon: merge table possible
Bug 30273 - merge tables: Can't lock file (errno: 155)
The problems were:
Bug 26379 - Combination of FLUSH TABLE and REPAIR TABLE
corrupts a MERGE table
1. A thread trying to lock a MERGE table performs busy waiting while
REPAIR TABLE or a similar table administration task is ongoing on
one or more of its MyISAM tables.
2. A thread trying to lock a MERGE table performs busy waiting until all
threads that did REPAIR TABLE or similar table administration tasks
on one or more of its MyISAM tables in LOCK TABLES segments do UNLOCK
TABLES. The difference against problem #1 is that the busy waiting
takes place *after* the administration task. It is terminated by
UNLOCK TABLES only.
3. Two FLUSH TABLES within a LOCK TABLES segment can invalidate the
lock. This does *not* require a MERGE table. The first FLUSH TABLES
can be replaced by any statement that requires other threads to
reopen the table. In 5.0 and 5.1 a single FLUSH TABLES can provoke
the problem.
Bug 26867 - LOCK TABLES + REPAIR + merge table result in
memory/cpu hogging
Trying DML on a MERGE table, which has a child locked and
repaired by another thread, made an infinite loop in the server.
Bug 26377 - Deadlock with MERGE and FLUSH TABLE
Locking a MERGE table and its children in parent-child order
and flushing the child deadlocked the server.
Bug 25038 - Waiting TRUNCATE
Truncating a MERGE child, while the MERGE table was in use,
let the truncate fail instead of waiting for the table to
become free.
Bug 25700 - merge base tables get corrupted by
optimize/analyze/repair table
Repairing a child of an open MERGE table corrupted the child.
It was necessary to FLUSH the child first.
Bug 30275 - Merge tables: flush tables or unlock tables
causes server to crash
Flushing and optimizing locked MERGE children crashed the server.
Bug 19627 - temporary merge table locking
Use of a temporary MERGE table with non-temporary children
could corrupt the children.
Temporary tables are never locked. So we do now prohibit
non-temporary chidlren of a temporary MERGE table.
Bug 27660 - Falcon: merge table possible
It was possible to create a MERGE table with non-MyISAM children.
Bug 30273 - merge tables: Can't lock file (errno: 155)
This was a Windows-only bug. Table administration statements
sometimes failed with "Can't lock file (errno: 155)".
These bugs are fixed by a new implementation of MERGE table open.
When opening a MERGE table in open_tables() we do now add the
child tables to the list of tables to be opened by open_tables()
(the "query_list"). The children are not opened in the handler at
this stage.
After opening the parent, open_tables() opens each child from the
now extended query_list. When the last child is opened, we remove
the children from the query_list again and attach the children to
the parent. This behaves similar to the old open. However it does
not open the MyISAM tables directly, but grabs them from the already
open children.
When closing a MERGE table in close_thread_table() we detach the
children only. Closing of the children is done implicitly because
they are in thd->open_tables.
For more detail see the comment at the top of ha_myisammrg.cc.
Changed from open_ltable() to open_and_lock_tables() in all places
that can be relevant for MERGE tables. The latter can handle tables
added to the list on the fly. When open_ltable() was used in a loop
over a list of tables, the list must be temporarily terminated
after every table for open_and_lock_tables().
table_list->required_type is set to FRMTYPE_TABLE to avoid open of
special tables. Handling of derived tables is suppressed.
These details are handled by the new function
open_n_lock_single_table(), which has nearly the same signature as
open_ltable() and can replace it in most cases.
In reopen_tables() some of the tables open by a thread can be
closed and reopened. When a MERGE child is affected, the parent
must be closed and reopened too. Closing of the parent is forced
before the first child is closed. Reopen happens in the order of
thd->open_tables. MERGE parents do not attach their children
automatically at open. This is done after all tables are reopened.
So all children are open when attaching them.
Special lock handling like mysql_lock_abort() or mysql_lock_remove()
needs to be suppressed for MERGE children or forwarded to the parent.
This depends on the situation. In loops over all open tables one
suppresses child lock handling. When a single table is touched,
forwarding is done.
Behavioral changes:
===================
This patch changes the behavior of temporary MERGE tables.
Temporary MERGE must have temporary children.
The old behavior was wrong. A temporary table is not locked. Hence
even non-temporary children were not locked. See
Bug 19627 - temporary merge table locking.
You cannot change the union list of a non-temporary MERGE table
when LOCK TABLES is in effect. The following does *not* work:
CREATE TABLE m1 ... ENGINE=MRG_MYISAM ...;
LOCK TABLES t1 WRITE, t2 WRITE, m1 WRITE;
ALTER TABLE m1 ... UNION=(t1,t2) ...;
However, you can do this with a temporary MERGE table.
You cannot create a MERGE table with CREATE ... SELECT, neither
as a temporary MERGE table, nor as a non-temporary MERGE table.
CREATE TABLE m1 ... ENGINE=MRG_MYISAM ... SELECT ...;
Gives error message: table is not BASE TABLE.
- Reserver namespace and place in frm for TABLE_CHECKSUM and PAGE_CHECKSUM create options
- Added syncing of directory when creating .frm files
- Portability fixes
- Added missing cast that could cause bugs
- Code cleanups
- Made some bit functions inline
- Moved things out of myisam.h to my_handler.h to make them more accessable
- Renamed some myisam variables and defines to make them more globaly usable (as they are used outside of MyISAM)
- Fixed bugs in error conditions
- Use compiler time asserts instead of run time
- Fixed indentation
HA_EXTRA_PREPARE_FOR_DELETE -> HA_EXTRA_PREPARE_FOR_DROP as the old name was wrong
(Added a define for old value to ensure we don't break any old code)
Added HA_EXTRA_PREPARE_FOR_RENAME as a signal for rename (before we used a DROP signal which is wrong)
- Initialize error messages early to get better errors when mysqld or an engine fails to start
- Fix windows bug that query_performance_frequency was not initialized if registry code failed
- thread_stack -> my_thread_stack_size
Faster thr_alarm()
Added 'Opened_files' status variable to track calls to my_open()
Don't give warnings when running mysql_install_db
Added option --source-install to mysql_install_db
I had to do the following renames() as used polymorphism didn't work with Forte compiler on 64 bit systems
index_read() -> index_read_map()
index_read_idx() -> index_read_idx_map()
index_read_last() -> index_read_last_map()
Bug#25422 (Hang with log tables)
Bug 17876 (Truncating mysql.slow_log in a SP after using cursor locks the
thread)
Bug 23044 (Warnings on flush of a log table)
Bug 29129 (Resetting general_log while the GLOBAL READ LOCK is set causes
a deadlock)
Prior to this fix, the server would hang when performing concurrent
ALTER TABLE or TRUNCATE TABLE statements against the LOG TABLES,
which are mysql.general_log and mysql.slow_log.
The root cause traces to the following code:
in sql_base.cc, open_table()
if (table->in_use != thd)
{
/* wait_for_condition will unlock LOCK_open for us */
wait_for_condition(thd, &LOCK_open, &COND_refresh);
}
The problem with this code is that the current implementation of the
LOGGER creates 'fake' THD objects, like
- Log_to_csv_event_handler::general_log_thd
- Log_to_csv_event_handler::slow_log_thd
which are not associated to a real thread running in the server,
so that waiting for these non-existing threads to release table locks
cause the dead lock.
In general, the design of Log_to_csv_event_handler does not fit into the
general architecture of the server, so that the concept of general_log_thd
and slow_log_thd has to be abandoned:
- this implementation does not work with table locking
- it will not work with commands like SHOW PROCESSLIST
- having the log tables always opened does not integrate well with DDL
operations / FLUSH TABLES / SET GLOBAL READ_ONLY
With this patch, the fundamental design of the LOGGER has been changed to:
- always open and close a log table when writing a log
- remove totally the usage of fake THD objects
- clarify how locking of log tables is implemented in general.
See WL#3984 for details related to the new locking design.
Additional changes (misc bugs exposed and fixed):
1)
mysqldump which would ignore some tables in dump_all_tables_in_db(),
but forget to ignore the same in dump_all_views_in_db().
2)
mysqldump would also issue an empty "LOCK TABLE" command when all the tables
to lock are to be ignored (numrows == 0), instead of not issuing the query.
3)
Internal errors handlers could intercept errors but not warnings
(see sql_error.cc).
4)
Implementing a nested call to open tables, for the performance schema tables,
exposed an existing bug in remove_table_from_cache(), which would perform:
in_use->some_tables_deleted=1;
against another thread, without any consideration about thread locking.
This call inside remove_table_from_cache() was not required anyway,
since calling mysql_lock_abort() takes care of aborting -- cleanly -- threads
that might hold a lock on a table.
This line (in_use->some_tables_deleted=1) has been removed.
