on Windows".
On platforms where read-write lock implementation does not
prefer readers by default (Windows, Solaris) server might
have deadlocked while detecting MDL deadlock.
MDL deadlock detector relies on the fact that read-write
locks which are used in its implementation prefer readers
(see new comment for MDL_lock::m_rwlock for details).
So far MDL code assumed that default implementation of
read/write locks for the system has this property.
Indeed, this turned out ot be wrong, for example, for
Windows or Solaris. Thus MDL deadlock detector might have
deadlocked on these systems.
This fix simply adds portable implementation of read/write
lock which prefer readers and changes MDL code to use this
new type of synchronization primitive.
No test case is added as existing rqg_mdl_stability test can
serve as one.
Extend and implement the grammar that allows to FLUSH WITH READ LOCK
a list of tables, rather than all of them.
Incompatible grammar change:
Previously one could perform FLUSH TABLES, HOSTS, PRIVILEGES in a single
statement.
After this change, FLUSH TABLES must always be alone on the list.
Judging by the test suite, however, the old extended syntax
was never or very rarely used.
The new statement requires RELOAD ACL global privilege and
LOCK_TABLES_ACL | SELECT_ACL on individual tables.
In other words, it's an atomic combination of LOCK TALBES <list> READ
and FLUSH TABLES <list>, and requires respective privileges.
For additional information about the semantics, please
see WL#5000 and the comment for flush_tables_with_read_lock()
function in sql_parse.cc
Before this fix, the performance schema file instrumentation would treat:
- a relative path to a file
- an absolute path to the same file
as two different files.
This would lead to:
- separate aggregation counters
- file leaks when a file is removed.
With this fix, a relative and absolute path are resolved to the same file instrument.
The problem was that ALTER TABLE on a merge table which was locked
using LOCK TABLE ... WRITE, by mistake gave
ER_TABLE_NOT_LOCKED_FOR_WRITE.
During opening of the table to be ALTERed, open_table() tried to
get an upgradable metadata lock. In LOCK TABLEs mode, this lock
must already exist (i.e. taken by LOCK TABLE) as new locks of this
type cannot be acquired for fear of deadlock. So in LOCK TABLEs
mode, open_table() tried to find an existing upgradable lock for
the table to be altered.
The problem was that open_table() also tried to find upgradable
metadata locks for children of merge tables even if no such
locks are needed to execute ALTER TABLE on merge tables.
This patch fixes the problem by making sure that open tables code
only searches for upgradable metadata locks for the merge table
and not for the merge children tables.
The patch also fixes a related bug where an upgradable metadata
lock was aquired outside of LOCK TABLEs mode even if the table in
question was temporary. This bug meant that LOCK TABLES or DDL on
temporary tables by mistake could be blocked/aborted by locks held
on base tables with the same table name by other connections.
Test cases added to merge.test and lock_multi.test.
The problem is that cond->fix_fields(thd, 0) breaks
condition(cuts off 'having'). The reason of that is
that NULL valued Item pointer is present in the
middle of Item list and it breaks the Item processing
loop.
performance degradation.
Filesort + join cache combination is preferred to full index scan because it
is usually faster. But it's not the case when the index is clustered one.
Now test_if_skip_sort_order function prefers filesort only if index isn't
clustered.
Attempts to execute RESET statements within a transaction that
had acquired metadata locks, led to an assertion failure on
debug servers. This bug didn't cause any problems on release
builds.
The triggered assert is designed to check that caches are not
flushed or reset while having active transactions. It is triggered
if acquired metadata locks exist that are not from LOCK TABLE or
HANDLER statements.
In this case it was triggered by RESET QUERY CACHE while having
an active transaction that had acquired locks. The reason the
assertion was triggered, was that RESET statements, unlike the
similar FLUSH statements, was not causing an implicit commit.
This patch fixes the problem by making sure RESET statements
commit the current transaction before executing. The commit
causes acquired metadata locks to be released, preventing the
assertion from being triggered.
Incompatible change: This patch changes RESET statements so
that they cause an implicit commit.
Test case added to query_cache.test.
Detailed revision comments:
r6669 | jyang | 2010-02-11 12:24:19 +0200 (Thu, 11 Feb 2010) | 7 lines
branches/5.1: Fix bug #50691, AIX implementation of readdir_r
causes InnoDB errors. readdir_r() returns an non-NULL value
in the case of reaching the end of a directory. It should
not be treated as an error return.
rb://238 approved by Marko
Detailed revision comments:
r6613 | inaam | 2010-02-09 20:23:09 +0200 (Tue, 09 Feb 2010) | 11 lines
branches/5.1: Fix Bug #38901
InnoDB logs error repeatedly when trying to load page into buffer pool
In buf_page_get_gen() if we are unable to read a page (because of
corruption or some other reason) we keep on retrying. This fills up
error log with millions of entries in no time and we'd eventually run
out of disk space. This patch limits the number of attempts that we
make (currently set to 100) and after that we abort with a message.
rb://241 Approved by: Heikki
Detailed revision comments:
r6545 | jyang | 2010-02-03 03:57:32 +0200 (Wed, 03 Feb 2010) | 8 lines
branches/5.1: Fix bug #49001, "SHOW INNODB STATUS deadlock info
incorrect when deadlock detection aborts". Print the correct
lock owner when recursive function lock_deadlock_recursive()
exceeds its maximum depth LOCK_MAX_DEPTH_IN_DEADLOCK_CHECK.
rb://217, approved by Marko.
Detailed revision comments:
r6538 | sunny | 2010-01-30 00:43:06 +0200 (Sat, 30 Jan 2010) | 6 lines
branches/5.1: Check *first_value every time against the column max
value and set *first_value to next autoinc if it's > col max value.
ie. not rely on what is passed in from MySQL.
[49497] Error 1467 (ER_AUTOINC_READ_FAILED) on inserting a negative value
rb://236
Detailed revision comments:
r6536 | sunny | 2010-01-30 00:13:42 +0200 (Sat, 30 Jan 2010) | 6 lines
branches/5.1: Check *first_value everytime against the column max
value and set *first_value to next autoinc if it's > col max value.
ie. not rely on what is passed in from MySQL.
[49497] Error 1467 (ER_AUTOINC_READ_FAILED) on inserting a negative value
rb://236
Detailed revision comments:
r6535 | sunny | 2010-01-30 00:08:40 +0200 (Sat, 30 Jan 2010) | 11 lines
branches/5.1: Undo the change from r6424. We need to return DB_SUCCESS even
if we were unable to initialize the tabe autoinc value. This is required for
the open to succeed. The only condition we currently treat as a hard error
is if the autoinc field instance passed in by MySQL is NULL.
Previously if the table autoinc value was 0 and the next value was requested
we had an assertion that would fail. Change that assertion and treat a value
of 0 to mean that the autoinc system is unavailable. Generation of next
value will now return failure.
rb://237
This change fixes test failure for partition_repair_myisam
and partition_recover_myisam.
The problem was that:
- the file std_data/corrupt_crash.MYI
contains charsetnr=63 (binary) for index segments.
- the new .frm file contains charsetnr=8 (latin1) for
the same segments.
As a result REPAIR refused to repair frm+MYI files
with different segment definition.
This fix restores the old behavior for frm and MYI files:
they now store charsetnr=63 for numeric/datetime data types.
The problem was incorrect escaping used inside a strnig : in \"$MYSQLD\" was written as "\MYSQL\"
(backslash and quote characters transposed), when defining FIND_PROC variable for BSD or SysV
style "ps" command-
Additionally fixed obvious code duplication and random naming in CHECK_PID test.
Propagation of a large unsigned numeric constant
in the WHERE expression led to wrong result.
For example,
"WHERE a = CAST(0xFFFFFFFFFFFFFFFF AS USIGNED) AND FOO(a)",
where a is an UNSIGNED BIGINT, and FOO() accepts strings,
was transformed to "... AND FOO('-1')".
That has been fixed.
Also EXPLAIN EXTENDED printed incorrect numeric constants in
transformed WHERE expressions like above. That has been
fixed too.
bool MDL_context::try_acquire_lock(MDL_request*)
This assert was triggered in the following way:
1) HANDLER OPEN t1 from connection 1
2) DROP TABLE t1 from connection 2. This will block due to the metadata lock
held by the open handler in connection 1.
3) DML statement (e.g. INSERT) from connection 1. This will close the table
opened by the HANDLER in 1) and release its metadata lock. This is done due
to the pending exclusive metadata lock from 2).
4) DROP TABLE t1 from connection 2 now completes and removes table t1.
5) HANDLER READ from connection 1. Since the handler table was closed in 3),
the handler code will try to reopen the table. First a new metadata lock on
t1 will be granted before the command fails since the table was removed in 4).
6) HANDLER READ from connection 1. This caused the assert.
The reason for the assert was that the MDL_request's pointer to the lock
ticket was not reset when the statement failed. HANDLER READ then tried to
acquire a lock using the same MDL_request object, triggering the assert.
This bug was only noticeable on debug builds and did not cause any problems
on release builds.
This patch fixes the problem by assuring that the pointer to the metadata
lock ticket is reset when reopening of handler tables fails.
Test case added to handler.inc
Crash happens in dlopen() code when trying to load the library. Crash does not happen when library is
not DTrace instrumented . Additionally, crash does not happen with default Solaris 10 GCC 3.4.3 and
it does not happen if main executable is instrumented.
So , just check for this specific situation (32 bit, GCC3.4.6 , Solaris) and disable Dtrace in shared libraries.
We have only single plugin so far that is instrumented (ha_example)
The problem was in an incorrect debug assertion. The expression
used in the failing assertion states that when finding
references matching ORDER BY expressions, there can be only one
reference to a single table. But that does not make any sense,
all test cases for this bug are valid examples with multiple
identical WHERE expressions referencing the same table which
are also present in the ORDER BY list.
Fixed by removing the failing assertion. We also have to take
care of the 'found' counter so that we count multiple
references only once. We rely on this fact later in
eq_ref_table().
