In a subselect all fields from outer selects are marked as dependent on
selects they are belong to. In some cases optimizer substitutes it for an
equivalent expression. For example "a_field IN (SELECT outer_field)" is
substituted with "a_field = outer_field". As we moved the outer_field to the
upper select it's not really outer anymore. But it was left marked as outer.
If exists an index over a_field optimizer choose wrong execution plan and thus
return wrong result.
Now the Item_in_subselect::single_value_transformer function removes dependent
marking from fields when a subselect is optimized away.
The "get_master_version_and_clock(...)" function in sql/slave.cc ignores
error and passes directly when queries fail, or queries succeed
but the result retrieved is empty.
The "get_master_version_and_clock(...)" function should try to reconnect master
if queries fail because of transient network problems, and fail otherwise.
The I/O thread should print a warning if the some system variables do not
exist on master (very old master)
table
The MERGE table storage engine does not support the HA_CAN_SQL_HANDLE feature
and any attempt to open the merge table will fail with ER_ILLEGAL_HA.
After an error occurred the tables that was opened must be closed again
or they will be left in an inconsistent state. However, the assumption
made in the code for closing and register handler tables was that only
one table will be opened, and this is not true for MERGE tables which
will cause multiple tables to open.
The next time a SELECT operation was issued on the merge table it
caused the system to freeze.
This patch fixes this issue by making sure that all tables which
are opened also are closed in the event of an error.
failed"
Do not assume that SQL prepared statements always run in text protocol.
When invoked from a stored procedure, which is itself invoked
by means of prepared CALL statement, the protocol may be binary.
Juggle with the protocol only when we want to change it
to binary in COM_STMT_EXECUTE, COM_STMT_PREPARE.
This is a backport from 5.4/6.0, where the bug was fixed
as part of WL#4264 "Backup: Stabilize Service Interface"
Fixed the following problems:
1. cmake 2.6 warning because of a changed default on
how the dependencies to libraries with a specified
path are resolved.
Fixed by requiring cmake 2.6.
2. Removed an obsolete pre-NT4 hack including defining
Windows system defines to alter the behavior of windows.h.
3. Disabled warning C4065 on compiling sql_yacc.cc because
of a know incompatibility in some of the newer bison binaries.
match against.
Server crashes when executing prepared statement with duplicating
MATCH() function calls in SELECT and ORDER BY expressions, e.g.:
SELECT MATCH(a) AGAINST('test') FROM t1 ORDER BY MATCH(a) AGAINST('test')
This query gets optimized by the server, so the value returned
by MATCH() from the SELECT list is reused for ORDER BY purposes.
To make this optimization server is comparing items from
SELECT and ORDER BY lists. We were getting server crash because
comparision function for MATCH() item is not intended to be called
at this point of execution.
In 5.0 and 5.1 this problem is workarounded by resetting MATCH()
item to the state as it was during PREPARE.
In 6.0 correct comparision function will be implemented and
duplicating MATCH() items from the ORDER BY list will be
optimized.
"create as select" (innodb table)
Problem: code constructing "CREATE TABLE..." statement
doesn't take into account that current database is not set
in some cases. That may lead to a server crash.
Fix: check if current database is set.
without error
When using quick access methods for searching rows in UPDATE or
DELETE there was no check if a fatal error was not already sent
to the client while evaluating the quick condition.
As a result a false OK (following the error) was sent to the
client and the error was thus transformed into a warning.
Fixed by checking for errors sent to the client during
SQL_SELECT::check_quick() and treating them as real errors.
Fixed a wrong test case in group_min_max.test
Fixed a wrong return code in mysql_update() and mysql_delete()
This patch is a follow up to http://lists.mysql.com/commits/76678.
When an allocation failure occurs for the buffer in the dynamic
array, an error condition was being set. The dynamic array is
usable even if the memory allocation fails. Since in most cases
the thread can continue to work without any problems the error
condition should not be set here.
This patch adds logic to remove the error condition from being set
when the memory allocation for the buffer in dynamic array fails.
mutually-nested subqueries
Queries of the form
SELECT * FROM (SELECT 1) AS t1,
(SELECT 2) AS t2,...
(SELECT 32) AS t32
caused the "Too high level of nesting for select" error
as if the query has a form
SELECT * FROM (SELECT 1 FROM (SELECT 2 FROM (SELECT 3 FROM...
The table_factor parser rule has been modified to adjust
the LEX::nest_level variable value after every derived table.
