WITH A VARIABLE AND ORDER BY
Bug#16035412 MYSQL SERVER 5.5.29 WRONG SORTING USING COMPLEX INDEX
This is a fix for a regression introduced by Bug#12667154:
Bug#12667154 attempted to fix a performance problem with subqueries
that did filesort. For doing filesort, the optimizer creates a quick
select object to use when building the sort index. This quick select
object was deleted after the first call to create_sort_index(). Thus,
for queries where the subquery was executed multiple times, the quick
object was only used for the first execution. For all later executions
of the subquery, filesort used a complete table scan for building the
sort index. The fix for Bug#12667154 tried to fix this by not deleting
the quick object after the first execution of create_sort_index() so
that it would be re-used for building the sort index by the following
executions of the subquery.
This regression introduced in Bug#12667154 is that due to not deleting
the quick select object after building the sort index, the quick
object could in some cases be used also during the second phase of the
execution of the subquery instead of using the created sort
index. This caused wrong results to be returned.
The fix for this issue is to delete the reference to the select object
after it has been used in create_sort_index(). In this way the select
and quick objects will not be available when doing the second phase
of the execution of the select operation. To ensure that the select
object can be re-used for the following executions of the subquery
we make a copy of the select pointer. This is used for restoring the
select object after the select operation is completed.
mysql-test/suite/innodb/r/innodb_mysql.result:
Changed explain output: The explain now contains "Using where" since we
have restored the select pointer after doing the filesort operation.
sql/sql_select.cc:
Change create_sort_index() so that it always sets the pointer to
the select object to NULL. This is done in order to avoid that the
select->quick object can be used when execution the main part of
the select operation.
sql/sql_select.h:
New member in JOIN_TAB: saved_select. Used by create_sort_index to
make a backup copy of the select pointer.
DIAGNOSTICS_AREA::SET_OK_STATUS
Use DBUG_RETURN() instead of return() if DBUG_ENTER() is
used in the function. This patch is to fix the Windows
pb2 failure on mysql-5.1
Approved by Marko. rb#1792
DIAGNOSTICS_AREA::SET_OK_STATUS
Test fails on 5.1 valgrind build. This is because of close(-1)
system call.
Fixed by adding extra checks for valid file descriptor.
Approved by Vasil(Calvin). rb#1792
I_MAIN.CTYPE_UTF8 FOR MACOSX10.6 FOR 5.1
While converting directory name to filename, a
file separator (FN_LIBCHAR) might get appended
to the resulting file name. This can result in
off-by-one error when length of the input string
is equal to FN_REFLEN. In this case, the terminating
'\0' gets written beyond the buffer allocated to store
the result.
Fixed by incrementing the dst buffer size by 1. As
extra safety, switched to strnmov() and added a debug
assert to check the length of the input file name.
No test case added as the scenario is already
covered by the test cases added for bugs in
the description.
Problem:If Disk becomes full while writing into the binlog,
then the server instance hangs till someone frees the space.
After user frees up the disk space, mysql server crashes
with an assert (m_status != DA_EMPTY)
Analysis: wait_for_free_space is being called in an
infinite loop i.e., server instance will hang until
someone frees up the space. So there is no need to
set status bit in diagnostic area.
Fix: Replace my_error/my_printf_error with
sql_print_warning() which prints the warning in error log.
include/my_sys.h:
Provision to call sql_print_warning from mysys files
mysys/errors.c:
Replace my_error/my_printf_error with
sql_print_warning() which prints the warning in error log.
mysys/my_error.c:
implementation of my_printf_warning
mysys/my_write.c:
Adding logic to break infinite loop in the simulation
sql/mysqld.cc:
Provision to call sql_print_warning from mysys files
Before this fix, configuring the server with:
- performance_schema_events_waits_history_size=0
- performance_schema_events_waits_history_long_size=0
could cause a crash in the performance schema.
These settings to 0 are intended to be valid and supported,
and are in fact working properly in mysql 5.6 and up already.
This fix backports the code fix and test cases from mysql 5.6
to the mysql 5.5 release.
Details of BUG#11746142: CALLING MYSQLD WHILE ANOTHER
INSTANCE IS RUNNING, REMOVES PID FILE
Fix: Before removing the pid file, ensure it was created
by the same process, leave it intact otherwise.
sql/mysqld.cc:
delete_pid_file() introduced, which checks that the pid file
belongs to the process before removing it
Some shell interpreters do not support '-e' test
primary to construct conditions.
man test 1 (on S10)
...skip...
-e file True if file exists. (Not available in sh.)
...skip...
Hence, check for the existence of a file using
'-e' might result in a syntax error on such
shell programs.
Fixed by replacing it by '-f'.
DOS ATTACKS
Problem:
For detailed description, see Bug#42502. This bug is a duplicate
of Bug#42502. The complete fix for Bug#42502 was not made as
proposed. Hence the bug still persists.
Fix:
Make the changes as proposed originally for the bugfix of 42502.
Which is to remove the allocation of the memory before we actually
check for any errors.
sql/tztime.cc:
Remove the double allocation for tz_info
TO SIGNED
Problem:
When we are joining types (of fields) in case of a union, we usually
upgrade the datatypes to the largest present in the query.
In case of mediumint, it is not happening.
Analysis:
When joined with types LONG and LONGLONG, mediumint should get
upgraded to LONG and LONGLONG respectively.
W.r.t the given query, constant '1' will be created as a LONGLONG
internally and SIGNED flag is enabled. As a result, while combining
types for the field, LONGLONG along with MEDIUMINT gets converted
to LONG first. LONG with MEDIUMINT(of the third select) gets converted
to MEDIUMINT. SIGNED FLAG would be that of the first field's.
As a result, the final result would be SIGNED MEDIUMINT.
Fix:
While joining types, MEDIUMINT with LONGLONG and MEDIUMINT with LONG
is converted to LONGLONG and LONG respectively. Also, made some
changes for FLOAT and DOUBLE.
sql/field.cc:
Changed merge types for MEDIUMINT.
The problem is a shift operation that is not 64-bit safe.
The consequence is that used tables information for a join with 32 tables
or more will be incorrect.
Fixed by adding a type cast in Item_sum::update_used_tables().
Also used the opportunity to fix some other potential bugs by adding an
explicit type-cast to an integer in a left-shift operation.
Some of them were quite harmless, but was fixed in order to get the same
signed-ness as the other operand of the operation it was used in.
sql/item_cmpfunc.cc
Adjusted signed-ness for some integers in left-shift.
sql/item_subselect.cc
Added type-cast to nesting_map (which is a 32/64 bit type, so
potential bug for deeply nested queries).
sql/item_sum.cc
Added type-cast to nesting_map (32/64-bit type) and table_map
(64-bit type).
sql/opt_range.cc
Added type-cast to ulonglong (which is a 64-bit type).
sql/sql_base.cc
Added type-cast to nesting_map (which is a 32/64-bit type).
sql/sql_select.cc
Added type-cast to nesting_map (32/64-bit type) and key_part_map
(64-bit type).
sql/strfunc.cc
Changed type-cast from longlong to ulonglong, to preserve signed-ness.
Analysis:
When thread cache is enabled, it does not properly initialize
thd->start_utime when a thread is picked from the thread cache.
This breaks the quota management mechanism.
THD::time_out_user_resource_limits() resets
m_user_connect->conn_per_hour to 0 based on thd->start_utime
Fix:
Initialize start_utime when cached thread is reused.
Notes:
Enabled back tests which were disabled because of this issue.
ON "DROP TABLE"
In the function ha_archive::write_row(), there is an error code path
that exits the function without releasing the mutex that was acquired
earlier.
rb#1743 approved by ramil.
HANG
Problem Statement:
When the operation RENAME TABLE is about rename the tablespace of the
table, it will stop all i/o operations on the tablespace temporarily.
For this the fil_space_t::stop_ios member is used.
Once the fil_space_t::stop_ios member is set to TRUE in the RENAME
TABLE operation, it is expected that no new i/o operation will be done
on the tablespace and all pending i/o operation can be completed on
the tablespace.
If the pending i/o operations initiate any new i/o operations then
there will be deadlock. The RENAME TABLE operation will be waiting
for pending i/o on the tablespace to be completed, and the pending i/o
operations will be waiting on the RENAME TABLE operation to set the
file_space_t::stop_ios flag to be set to FALSE.
But in the given scenario the pending i/o operations did not initiate
new i/o. But they where still unnecessarily checking the
fil_space_t::stop_ios flag. This resulted in deadlock.
Solution:
I noticed that this deadlock happens in fil_space_get_size() and
fil_space_get_zip_size() in the i/o threads. These functions check
the stop_ios flag even when no i/o will be initiated. I modified
these functions to ensure that they check the stop_ios flag only when
they will be initiating an i/o operation. This solves the problem.
rb://1635 (mysql-5.5)
rb://1660 (mysql-trunk) approved by Inaam, Jimmy, and ima.
DTUPLE_CREATE_FROM_MEM()
Align to word-size the memory occupied by tuple_buf[] memory chunk.
I confirm that this change fixes the SIGBUS on Solaris.
Approved by: Marko (via IM)
