Problem 1:
When the 'Using index' optimization is used, the optimizer may still - after
cost-based optimization - decide to use another index in order to avoid using
a temporary table. But when this happens, the flag to the storage engine to
read index only (not table) was still set. Fixed by resetting the flag in the
storage engine and TABLE structure in the above scenario, unless the new index
allows for the same optimization.
Problem 2:
When a 'ref' access method was employed by cost-based optimizer, (when the column
is non-NULLable), it was assumed that it needed no initialization if 'quick' access
methods (since they are based on range scan). When ORDER BY optimization overrides
the decision, however, it expects to have this initialized and hence crashes.
Fixed in 5.1 (was fixed in 6.0 already) by initializing 'quick' even when there's
'ref' access.
column on partitioned table
An assertion 'ASSERT_COULUMN_MARKED_FOR_READ' is failed if the query
is executed with index containing double column on partitioned table.
The problem is that assertion expects all the fields which are read,
to be in the read_set.
In this query only the field 'a' is in the readset as the tables in
the query are joined by the field 'a' and so the assertion fails
expecting other field 'b'.
Since the function cmp() is just comparison of two parameters passed,
the assertion is not required.
Fixed by removing the assertion in the double fields comparision
function and also fixed the index initialization to do ordered
index scan with RW LOCK which ensures all the fields from a key are in
the read_set.
Note: this bug is not reproducible with other datatypes because the
assertion doesn't exist in comparision function for other
datatypes.
when used with --tab
1) New syntax: added CHARACTER SET clause to the
SELECT ... INTO OUTFILE (to complement the same clause in
LOAD DATA INFILE).
mysqldump is updated to use this in --tab mode.
2) ESCAPED BY/ENCLOSED BY field parameters are documented as
accepting CHAR argument, however SELECT .. INTO OUTFILE
silently ignored rests of multisymbol arguments.
For the symmetrical behavior with LOAD DATA INFILE the
server has been modified to fail with the same error:
ERROR 42000: Field separator argument is not what is
expected; check the manual
3) Current LOAD DATA INFILE recognizes field/line separators
"as is" without converting from client charset to data
file charset. So, it is supposed, that input file of
LOAD DATA INFILE consists of data in one charset and
separators in other charset. For the compatibility with
that [buggy] behaviour SELECT INTO OUTFILE implementation
has been saved "as is" too, but the new warning message
has been added:
Non-ASCII separator arguments are not fully supported
This message warns on field/line separators that contain
non-ASCII symbols.
We disallow the partitioning of a log table. You could however
partition a table first, and then point logging to it. This is
not only against the docs, it also crashes the server.
We catch this case now.
A REPLACE in the MERGE engine is actually a REPLACE
into one (FIRST or LAST) of the underlying MyISAM
tables. So in effect the server works on the meta
data of the MERGE table, while the real insert happens
in the MyISAM table.
The MERGE table has no index, while MyISAM has a
unique index. When a REPLACE into a MERGE table (
and the REPLACE conflicts with a duplicate in a
child table) is done, we try to access the duplicate
key information for the MERGE table. This information
actually does not exist, hence this results in a crash.
The problem can be resolved by modifying the MERGE
engine to provide us the duplicate key information
directly, instead of just returning the MyISAM index
number as the error key. Then the SQL layer (or "the
server") does not try to access the key_info of the
MERGE table, which does not exist.
The current patch modifies the MERGE engine to provide
the position for a record where a unique key violation
occurs.
an assertion in a debug build.
The reason is that the C API doesn't support multiple result sets for prepared
statements and attempting to execute a stored routine which returns multiple result
sets sometimes lead to a network error. The network error sets the diagnostic area
prematurely which later leads to the assert when an attempt is made to set a second
server state.
This patch fixes the issue by changing the scope of the error code returned by
sp_instr_stmt::execute() to include any error which happened during the execution.
To assure that Diagnostic_area::is_sent really mean that the message was sent all
network related functions are checked for return status.
those keywords do nothing in 5.1 (they are meant for future versions, for example featuring the Maria engine)
so they are here removed from the syntax. Adding those keywords to future versions when needed is:
- WL#5034 "Add TRANSACTIONA=0|1 and PAGE_CHECKSUM=0|1 clauses to CREATE TABLE"
- WL#5037 "New ROW_FORMAT value for CREATE TABLE: PAGE"
consumption (CPU) for upgrading a large log table can be intense.
Therefore, truncate the general_log table beforehand if running
mysql_upgrade test with Valgrind.
One of the tests introduced for this bug was failing
because of path size restriction in windows.
Moved the test case to a new test which is disabled under windows.
In create_myisam_from_heap() mark all errors as fatal except
HA_ERR_RECORD_FILE_FULL for a HEAP table.
Not doing so could lead to problems, e.g. in a case when a
temporary MyISAM table gets overrun due to its MAX_ROWS limit
while executing INSERT/REPLACE IGNORE ... SELECT.
The SELECT execution was aborted, but the error was
converted to a warning due to IGNORE clause, so neither 'ok'
nor 'error' packet could be sent back to the client. This
condition led to hanging client when using 5.0 server, or
assertion failure in 5.1.
Problem was that a failing rename just left the partitions at the state
it was at the failure.
Solution was to try to revert the started rename if a failure occured.
When during the optimization an item is moved to the upper select
the item's context left unchanged. This caused wrong result in the
PS/SP mode.
The Item_ident::remove_dependence_processor now sets the context
of the select to which the item is moved to.
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.
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.
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.
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()
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.
