NEW_FRM_MEM WITHOUT NEEDING TO".
During the process of opening tables for a statement, we allocated
memory which was used only during view loading even in cases when the
statement didn't use any views. Such an unnecessary allocation (and
corresponding freeing) might have caused significant performance
overhead in some workloads. For example, it caused up to 15% slowdown
in a simple stored routine calculating Fibonacci's numbers.
This memory was pre-allocated as part of "new_frm_mem" MEM_ROOT
initialization at the beginning of open_tables().
This patch addresses this issue by turning off memory pre-allocation
during initialization for this MEM_ROOT. Now, memory on this root
will be allocated only at the point when the first .FRM for a view is
opened.
The patch doesn't contain a test case since it is hard to test the
performance improvements or the absence of memory allocation in our
test framework.
There is an optimization of DISTINCT in JOIN::optimize()
which depends on THD::used_tables value. Each SELECT statement
inside SP resets used_tables value(see mysql_select()) and it
leads to wrong result. The fix is to replace THD::used_tables
with LEX::used_tables.
SHOW ALL PROBLEMS FOR MERGE TABLE COMPLIANCE IN 5.1".
The problem was that CHECK/REPAIR TABLE for a MERGE table which
had several children missing or in wrong engine reported only
issue with the first such table in its result-set. While in 5.0
this statement returned the whole list of problematic tables.
Ability to report problems for all children was lost during
significant refactorings of MERGE code which were done as part
of work on 5.1 and 5.5 releases.
This patch restores status quo ante refactorings by changing
code in such a way that:
1) Failure to open child table due to its absence during CHECK/
REPAIR TABLE for a MERGE table is not reported immediately
when its absence is discovered in open_tables(). Instead
handling/error reporting in such a situation is postponed
until the moment when children are attached.
2) Code performing attaching of children no longer stops when
it encounters first problem with one of the children during
CHECK/REPAIR TABLE. Instead it continues iteration through
the child list until all problems caused by child absence/
wrong engine are reported.
Note that even after this change problem with mismatch of
child/parent definition won't be reported if there is also
another child missing, but this is how it was in 5.0 as well.
In sql_class.cc, 'row_count', of type 'ha_rows', was used as last argument for
ER_TRUNCATED_WRONG_VALUE_FOR_FIELD which is
"Incorrect %-.32s value: '%-.128s' for column '%.192s' at row %ld".
So 'ha_rows' was used as 'long'.
On SPARC32 Solaris builds, 'long' is 4 bytes and 'ha_rows' is 'longlong' i.e. 8 bytes.
So the printf-like code was reading only the first 4 bytes.
Because the CPU is big-endian, 1LL is 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x01
so the first four bytes yield 0. So the warning message had "row 0" instead of
"row 1" in test outfile_loaddata.test:
-Warning 1366 Incorrect string value: '\xE1\xE2\xF7' for column 'b' at row 1
+Warning 1366 Incorrect string value: '\xE1\xE2\xF7' for column 'b' at row 0
All error-messaging functions which internally invoke some printf-life function
are potential candidate for such mistakes.
One apparently easy way to catch such mistakes is to use
ATTRIBUTE_FORMAT (from my_attribute.h).
But this works only when call site has both:
a) the format as a string literal
b) the types of arguments.
So:
func(ER(ER_BLAH), 10);
will silently not be checked, because ER(ER_BLAH) is not known at
compile time (it is known at run-time, and depends on the chosen
language).
And
func("%s", a va_list argument);
has the same problem, as the *real* type of arguments is not
known at this site at compile time (it's known in some caller).
Moreover,
func(ER(ER_BLAH));
though possibly correct (if ER(ER_BLAH) has no '%' markers), will not
compile (gcc says "error: format not a string literal and no format
arguments").
Consequences:
1) ATTRIBUTE_FORMAT is here added only to functions which in practice
take "string literal" formats: "my_error_reporter" and "print_admin_msg".
2) it cannot be added to the other functions: my_error(),
push_warning_printf(), Table_check_intact::report_error(),
general_log_print().
To do a one-time check of functions listed in (2), the following
"static code analysis" has been done:
1) replace
my_error(ER_xxx, arguments for substitution in format)
with the equivalent
my_printf_error(ER_xxx,ER(ER_xxx), arguments for substitution in
format),
so that we have ER(ER_xxx) and the arguments *in the same call site*
2) add ATTRIBUTE_FORMAT to push_warning_printf(),
Table_check_intact::report_error(), general_log_print()
3) replace ER(xxx) with the hard-coded English text found in
errmsg.txt (like: ER(ER_UNKNOWN_ERROR) is replaced with
"Unknown error"), so that a call site has the format as string literal
4) this way, ATTRIBUTE_FORMAT can effectively do its job
5) compile, fix errors detected by ATTRIBUTE_FORMAT
6) revert steps 1-2-3.
The present patch has no compiler error when submitted again to the
static code analysis above.
It cannot catch all problems though: see Field::set_warning(), in
which a call to push_warning_printf() has a variable error
(thus, not replacable by a string literal); I checked set_warning() calls
by hand though.
See also WL 5883 for one proposal to avoid such bugs from appearing
again in the future.
The issues fixed in the patch are:
a) mismatch in types (like 'int' passed to '%ld')
b) more arguments passed than specified in the format.
This patch resolves mismatches by changing the type/number of arguments,
not by changing error messages of sql/share/errmsg.txt. The latter would be wrong,
per the following old rule: errmsg.txt must be as stable as possible; no insertions
or deletions of messages, no changes of type or number of printf-like format specifiers,
are allowed, as long as the change impacts a message already released in a GA version.
If this rule is not followed:
- Connectors, which use error message numbers, will be confused (by insertions/deletions
of messages)
- using errmsg.sys of MySQL 5.1.n with mysqld of MySQL 5.1.(n+1)
could produce wrong messages or crash; such usage can easily happen if
installing 5.1.(n+1) while /etc/my.cnf still has --language=/path/to/5.1.n/xxx;
or if copying mysqld from 5.1.(n+1) into a 5.1.n installation.
When fixing b), I have verified that the superfluous arguments were not used in the format
in the first 5.1 GA (5.1.30 'bteam@astra04-20081114162938-z8mctjp6st27uobm').
Had they been used, then passing them today, even if the message doesn't use them
anymore, would have been necessary, as explained above.
TRX->CONC_STATE == 0 || TRX->CONC_STATE == 1
This bug was a different manifestation of Bug#11766752,
which was previously only fixed on mysql-trunk.
This patch backports the fix for Bug#11766752 to mysql-5.5,
which fixes the problem. The patch also adds some extra test
coverage.
ASSERTION TABLE->DB_STAT FAILED IN
SQL_BASE.CC::OPEN_TABLE() DURING I_S Q
This assert could be triggered if a statement requiring a name
lock on a table (e.g. DROP TRIGGER) executed concurrently
with an I_S query which also used the table.
One connection first started an I_S query that opened a given table.
Then another connection started a statement requiring a name lock
on the same table. This statement was blocked since the table was
in use by the I_S query. When the I_S query resumed and tried to
open the table again as part of get_all_tables(), it would encounter
a table instance with an old version number representing the pending
name lock. Since I_S queries ignore version checks and thus pending
name locks, it would try to continue. This caused it to encounter
the assert. The assert checked that the TABLE instance found with a
different version, was a real, open table. However, since this TABLE
instance instead represented a pending name lock, the check would
fail and trigger the assert.
This patch fixes the problem by removing the assert. It is ok for
TABLE::db_stat to be 0 in this case since the TABLE instance can
represent a pending name lock.
Test case added to lock_sync.test.
FAILS IN SET_FIELD_ITERATOR
(Former 59299)
When a PROCEDURE does a natural join, resolving of which columns are
used in the join is done only once; consecutive CALLs to the procedure
will reuse this information:
CREATE PROCEDURE proc() SELECT * FROM t1 NATURAL JOIN v1;
CALL proc(); <- natural join columns resolved here
CALL proc(); <- reuse resolved NJ columns from first CALL
The second CALL knows that it can reuse the resolved NJ columns because
the first CALL sets st_select_lex::first_natural_join_processing=false.
The problem in this bug was that the table the view v1 depends on
changed between CREATE PROCEDURE and the first CALL:
CREATE PROCEDURE...
ALTER TABLE t2 CHANGE COLUMN a b CHAR;
CALL proc(); <- error when resolving natural join columns
CALL proc(); <- tries to reuse from first CALL => crash
The fix for this bug is to set first_natural_join_processing= FALSE iff
the natural join columns resolving was successful.
FLUSH TABLES under FLUSH TABLES <list> WITH READ LOCK leads
to assert failure.
This assert was triggered if a statement tried up upgrade a metadata
lock with an active FLUSH TABLE <list> WITH READ LOCK. The assert
checks that the connection already holds a global intention exclusive
metadata lock. However, FLUSH TABLE <list> WITH READ LOCK does not
acquire this lock in order to be compatible with FLUSH TABLES WITH
READ LOCK. Therefore any metadata lock upgrade caused the assert to
be triggered.
This patch fixes the problem by preventing metadata lock upgrade
if the connection has an active FLUSH TABLE <list> WITH READ LOCK.
ER_TABLE_NOT_LOCKED_FOR_WRITE will instead be reported to the client.
Test case added to flush.test.
to crash mysqld".
handler::pushed_cond was not always properly reset when table objects where
recycled via the table cache.
handler::pushed_cond is now set to NULL in handler::ha_reset(). This should
prevent pushed conditions from (incorrectly) re-apperaring in later queries.
- Removed files specific to compiling on OS/2
- Removed files specific to SCO Unix packaging
- Removed "libmysqld/copyright", text is included in documentation
- Removed LaTeX headers for NDB Doxygen documentation
- Removed obsolete NDB files
- Removed "mkisofs" binaries
- Removed the "cvs2cl.pl" script
- Changed a few GPL texts to use "program" instead of "library"
temptable views
The TABLE::key_read field indicates if the optimizer has found that row
retrieval only should access the index tree. The triggered assert
inside close_thread_table() checks that this field has been reset when
the table is about to be closed.
During normal execution, these fields are reset right before tables are
closed at the end of mysql_execute_command(). But in the case of errors,
tables are closed earlier. The patch for Bug#52044 refactored the open
tables code so that close_thread_tables() is called immediately if
opening of tables fails. At this point in the execution, it could
happend that all TABLE::key_read fields had not been properly reset,
therefore triggering the assert.
The problematic statement in this case was EXPLAIN where the query
accessed two derived tables and where the first derived table was
processed successfully while the second derived table was not.
Since it was an EXPLAIN, TABLE::key_read fields were not reset after
successful derived table processing since the state needs to be
accessible afterwards. When processing of the second derived table
failed, it's corresponding SELECT_LEX_UNIT was cleaned, which caused
it's TABLE::key_read fields to be reset. Since processing failed,
the error path of open_and_lock_tables() was entered and
close_thread_tables() was called. The assert was then triggered due
to the TABLE::key_read fields set during processing of the first
derived table.
This patch fixes the problem by adding a new derived table processor,
mysql_derived_cleanup() that is called after mysql_derived_filling().
It causes cleanup of all SELECT_LEX_UNITs to be called, resetting
all relevant TABLE::key_read fields.
Test case added to derived.test.
The user-visible problem was that changes to column-level privileges,
happened in between of PREPARE and EXECUTE of a prepared statement, were
neglected. I.e. a prepared statement could be executed with the
column-level privileges as of PREPARE-time. The problem existed for
column-level privileges only.
A similar problem existed for stored programs: the changes between
executions didn't have an effect.
Technically the thing is that table references are cached in
Prepared_statement::prepare() call. In subsequent
Prepared_statement::execute() calls those cached values are used.
There are two functions to get a field by name: find_field_in_table() and
find_field_in_table_ref(). On prepare-phase find_field_in_table_ref() is
called, on execute-phase -- find_field_in_table() because the table is
cached. find_field_in_table() does not check column-level privileges and
expects the caller to do that. The problem was that this check was
forgotten.
The fix is to check them there as it happens in find_field_in_table_ref().
bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ
LOCK" and bug #54673 "It takes too long to get readlock for
'FLUSH TABLES WITH READ LOCK'".
The first bug manifested itself as a deadlock which occurred
when a connection, which had some table open through HANDLER
statement, tried to update some data through DML statement
while another connection tried to execute FLUSH TABLES WITH
READ LOCK concurrently.
What happened was that FTWRL in the second connection managed
to perform first step of GRL acquisition and thus blocked all
upcoming DML. After that it started to wait for table open
through HANDLER statement to be flushed. When the first connection
tried to execute DML it has started to wait for GRL/the second
connection creating deadlock.
The second bug manifested itself as starvation of FLUSH TABLES
WITH READ LOCK statements in cases when there was a constant
stream of concurrent DML statements (in two or more
connections).
This has happened because requests for protection against GRL
which were acquired by DML statements were ignoring presence of
pending GRL and thus the latter was starved.
This patch solves both these problems by re-implementing GRL
using metadata locks.
Similar to the old implementation acquisition of GRL in new
implementation is two-step. During the first step we block
all concurrent DML and DDL statements by acquiring global S
metadata lock (each DML and DDL statement acquires global IX
lock for its duration). During the second step we block commits
by acquiring global S lock in COMMIT namespace (commit code
acquires global IX lock in this namespace).
Note that unlike in old implementation acquisition of
protection against GRL in DML and DDL is semi-automatic.
We assume that any statement which should be blocked by GRL
will either open and acquires write-lock on tables or acquires
metadata locks on objects it is going to modify. For any such
statement global IX metadata lock is automatically acquired
for its duration.
The first problem is solved because waits for GRL become
visible to deadlock detector in metadata locking subsystem
and thus deadlocks like one in the first bug become impossible.
The second problem is solved because global S locks which
are used for GRL implementation are given preference over
IX locks which are acquired by concurrent DML (and we can
switch to fair scheduling in future if needed).
Important change:
FTWRL/GRL no longer blocks DML and DDL on temporary tables.
Before this patch behavior was not consistent in this respect:
in some cases DML/DDL statements on temporary tables were
blocked while in others they were not. Since the main use cases
for FTWRL are various forms of backups and temporary tables are
not preserved during backups we have opted for consistently
allowing DML/DDL on temporary tables during FTWRL/GRL.
Important change:
This patch changes thread state names which are used when
DML/DDL of FTWRL is waiting for global read lock. It is now
either "Waiting for global read lock" or "Waiting for commit
lock" depending on the stage on which FTWRL is.
Incompatible change:
To solve deadlock in events code which was exposed by this
patch we have to replace LOCK_event_metadata mutex with
metadata locks on events. As result we have to prohibit
DDL on events under LOCK TABLES.
This patch also adds extensive test coverage for interaction
of DML/DDL and FTWRL.
Performance of new and old global read lock implementations
in sysbench tests were compared. There were no significant
difference between new and old implementations.
sql_show.cc during rqg_info_schema test on Windows".
Ensure we do not access freed memory when filling
information_schema.views when one of the views
could not be properly opened.
|| thd->in_sub_stmt || (thd->state..
Don't rollback statement transactions if we are in a sub-statement.
This could for example happen for open_ltable() when opening the
general log during execution of a stored procedure.
thd->in_sub_stmt || (thd->state..
OPTIMIZE TABLE is not directly supported by InnoDB. Instead,
recreate and analyze of the table is done. After recreate,
the table is closed and locks are released before the table
is reopened and locks re-acquired for the analyze phase.
This assertion was triggered if OPTIMIZE TABLE failed to
acquire thr_lock locks before starting the analyze phase.
The assertion tests (among other things) that there no
active statement transaction. However, as part of acquiring
the thr_lock lock, external_lock() is called for InnoDB
tables and this causes a statement transaction to be started.
If thr_multi_lock() later fails (e.g. due to timeout),
the failure handling code causes this assert to be triggered.
This patch fixes the problem by doing rollback of the
current statement transaction in case open_ltable (used by
OPTIMIZE TABLE) fails to acquire thr_lock locks.
Test case added to lock_sync.test.
After ALTER TABLE which changed only table's metadata, row-based
binlog sometimes got corrupted since the tablemap was unexpectedly
set to 0 for subsequent updates to the same table.
ALTER TABLE which changed only table's metadata always reset
table_map_id for the table share to 0. Despite the fact that
0 is a valid value for table_map_id, this step caused problems
as it could have created situation in which we had more than
one table share with table_map_id equal 0. If more than one
table with table_map_id are 0 were updated in the same statement,
updates to these different tables were written into the same
rows event. This caused slave server to crash.
This bug happens only on 5.1. It doesn't affect 5.5+.
This patch solves this problem by ensuring that ALTER TABLE
statements which change metadata only never reset table_map_id
to 0. To do this it changes reopen_table() to correctly use
refreshed table_map_id value instead of using the old one/
resetting it.
tables".
Attempting to issue an INSERT DELAYED statement for a MERGE
table might have caused a deadlock if it happened as part of
a transaction or under LOCK TABLES, and there was a concurrent
DDL or LOCK TABLES ... WRITE statement which tried to lock one
of its underlying tables.
The problem occurred when a delayed insert handler thread tried
to open a MERGE table and discovered that to do this it had also
to open all underlying tables and hence acquire metadata
locks on them. Since metadata locks on the underlying tables were
not pre-acquired by the connection thread executing INSERT DELAYED,
attempts to do so might lead to waiting. In this case the
connection thread had to wait for the delayed insert thread.
If the thread which was preventing the lock on the underlying table
from being acquired had to wait for the connection thread (due to
this or other metadata locks), a deadlock occurred.
This deadlock was not detected by the MDL deadlock detector since
waiting for the handler thread by the connection thread is not
represented in the wait-for graph.
This patch solves the problem by ensuring that the delayed
insert handler thread never tries to open underlying tables
of a MERGE table. Instead open_tables() is aborted right after
the parent table is opened and a ER_DELAYED_NOT_SUPPORTED
error is emitted (which is passed to the connection thread and
ultimately to the user).
table causes assert failure".
Attempting to use FLUSH TABLE table_list WITH READ LOCK
statement for a MERGE table led to an assertion failure if
one of its children was not present in the list of tables
to be flushed. The problem was not visible in non-debug builds.
The assertion failure was caused by the fact that in such
situations FLUSH TABLES table_list WITH READ LOCK implementation
tried to use (e.g. lock) such child tables without acquiring
metadata lock on them. This happened because when opening tables
we assumed metadata locks on all tables were already acquired
earlier during statement execution and a such assumption was
false for MERGE children.
This patch fixes the problem by ensuring at open_tables() time
that we try to acquire metadata locks on all tables to be opened.
For normal tables such requests are satisfied instantly since
locks are already acquired for them. For MERGE children metadata
locks are acquired in normal fashion.
Note that FLUSH TABLES merge_table WITH READ LOCK will lock for
read both the MERGE table and its children but will flush only
the MERGE table. To flush children one has to mention them in table
list explicitly. This is expected behavior and it is consistent with
usage patterns for this statement (e.g. in mysqlhotcopy script).
MDL deadlock detector".
Deadlock could have occurred when workload containing mix
of DML, DDL and FLUSH TABLES statements affecting same
set of tables was executed in heavily concurrent environment.
This deadlock occurred when several connections tried to
perform deadlock detection in metadata locking subsystem.
The first connection started traversing wait-for graph,
encountered sub-graph representing wait for flush, acquired
LOCK_open and dived into sub-graph inspection. When it has
encounterd sub-graph corresponding to wait for metadata lock
and blocked while trying to acquire rd-lock on
MDL_lock::m_rwlock (*) protecting this subgraph, since some
other thread had wr-lock on it. When this wr-lock was released
it could have happened (if there was other pending wr-lock
against this rwlock) that rd-lock from the first connection
was left unsatisfied but at the same time new rd-lock request
from the second connection sneaked in and was satisfied (for
this to be possible second rd- request should come exactly
after wr-lock is released but before pending wr-lock manages
to grab rwlock, which is possible both on Linux and in our
own rwlock implementation). If this second connection
continued traversing wait-for graph and encountered sub-graph
representing wait for flush it tried to acquire LOCK_open
and thus deadlock was created.
This patch tries to workaround this problem but not allowing
deadlock detector to lock LOCK_open mutex if some other thread
doing deadlock detection already owns it and current search
depth is greater than 0. Instead deadlock is reported.
Other possible solutions are either known to have negative
effects on performance or require much more time for proper
implementation and testing.
No test case is provided as this bug is very hard to repeat
in MTR environment but is repeatable with the help of RQG
tests.
to allow temp table operations) -- prerequisite patch #3.
Rename open_temporary_table() to open_table_uncached().
open_temporary_table() will be introduced in following patches
to open temporary tables for a statement.
to allow temp table operations) -- prerequisite patch #2.
Introduce a new form of find_temporary_table() function:
find_temporary_table() by a table key. It will be used
in further patches.
Replace find_temporary_table(table_list->db, table_list->name)
by more appropiate find_temporary_table(table_list) across
the codebase.
to allow temp table operations) -- prerequisite patch #1.
Move a piece of code that initialiazes TABLE instance
after it was successfully opened into a separate function.
This function will be reused in the following patches.
on CREATE TABLE .. SELECT I_S.PART
This assert was triggered if an InnoDB table was created using
CREATE TABLE ... AS SELECT where the query used an I_S table, and
a view existed in the database. It would also be triggered for
any statement changing an InnoDB table (e.g. INSERT, UPDATE, DELETE)
which had a subquery referencing an I_S table.
The assert was triggered if open_normal_and_derived_tables() failed
and a statement transaction had been started. This will usually not
happen as tables are opened before a statement transaction is started.
However, e.g. CREATE TABLE ... AS SELECT starts a transaction in order
to insert tuples into the new table. And if the subquery references
an I_S table, all current tables and views can be opened in order to
fill the I_S table on the fly. If a view is discovered, open will fail
as it is instructed to open tables only (OPEN_TABLE_ONLY). This would
cause the assert to be triggered.
The assert was added in the patch for Bug#52044 and was therefore
not in any released versions of the server.
This patch fixes the problem by adjusting the assert to take into
consideration the possibility of tables being opened as part of
an I_S query. This is similar to what is already done for
close_tables_for_reopen().
Test case added to information_schema_inno.test.
temp table
This patch introduces two key changes in the replication's behavior.
Firstly, it reverts part of BUG#51894 which puts any update to temporary tables
into the trx-cache. Now, updates to temporary tables are handled according to
the type of their engines as a regular table.
Secondly, an unsafe mixed statement, (i.e. a statement that access transactional
table as well non-transactional or temporary table, and writes to any of them),
are written into the trx-cache in order to minimize errors in the execution when
the statement logging format is in use.
Such changes has a direct impact on which statements are classified as unsafe
statements and thus part of BUG#53259 is reverted.
check_if_table_exists()
This assert was triggered when the server tried to load plugins
while running in embedded server mode. In embedded server mode,
check_if_table_exists() was used to check if mysql.plugin existed
so that ER_NO_SUCH_TABLE could be silently ignored.
The problem was that this check was done without acquiring a metadata
lock on mysql.plugin first. This triggered the assert.
This patch fixes the problem by removing the call to
check_if_table_exists() from plugin_load(). Instead an error handler
which traps ER_NO_SUCH_TABLE is installed before trying to open
mysql.plugin when running in embedded server mode.
No test coverage added since this assert was triggered by
existing tests running in embedded server mode.
'CREATE TABLE IF NOT EXISTS ... SELECT' behaviour
BUG#47132, BUG#47442, BUG49494, BUG#23992 and BUG#48814 will disappear
automatically after the this patch.
BUG#55617 is fixed by this patch too.
This is the 5.5 part.
It implements:
- 'CREATE TABLE IF NOT EXISTS ... SELECT' statement will not insert
anything and binlog anything if the table already exists.
It only generate a warning that table already exists.
- A couple of test cases for the behavior changing.
corruption on ADD PARTITION and LOCK TABLE
Bug#53770: Server crash at handler.cc:2076 on
LOAD DATA after timed out COALESCE PARTITION
5.5 fix for:
Bug#51042: REORGANIZE PARTITION can leave table in an
inconsistent state in case of crash
Needs to be back-ported to 5.1
5.5 fix for:
Bug#50418: DROP PARTITION does not interact with
transactions
Main problem was non-persistent operations done
before meta-data lock was taken (53770+53676).
And 53676 needed to keep the table/partitions opened and locked
while copying the data to the new partitions.
Also added thorough tests to spot some additional bugs
in the ddl_log code, which could result in bad state
between the .frm and partitions.
Collapsed patch, includes all fixes required from the reviewers.
