A rule was introduced by the 5.1 part of the fix for bug 27531 to
prefer filesort over indexed ORDER BY when accessing all of the rows of a
table (because it's faster). This new rule was not accounting for the
presence of a LIMIT clause.
Fixed the condition for this rule so it will prefer filesort over
indexed ORDER BY only if no LIMIT.
As the result of DOUBLE claculations can be bigger
than DBL_MAX constant we use in code, we shouldn't use this constatn
as a biggest possible value.
Particularly the rtree_pick_key function set 'min_area= DBL_MAX' relying
that any rtree_area_increase result will be less so we return valid
key. Though in rtree_area_increase function we calculate the area
of the rectangle, so the result can be 'inf' if the rectangle is
huge enough, which is bigger than DBL_MAX.
Code of the rtree_pick_key modified so we always return a valid key.
The Item_func_rollup_const class is used for wrapping constants to avoid
wrong result for ROLLUP queries with DISTINCT and a constant in the select
list. This class is also used to wrap up a NULL constant but its null_value
wasn't set accordingly. This led to a server crash.
Now the null_value of an object of the Item_func_rollup_const class is set
by its fix_length_and_dec member function.
mysqldump adds the "-- Dump completed on YYYY-MM-DD hh:mm:ss" string
to the end of output if the --comments switch is on.
The only way to suppress this line is to use --skip-comments/--compact
switch.
New switch has been added to the mysqldump client command line:
--dump-date.
For the compatibility with previous releases, by default the --dump-date
is on.
The --dump-date switch forces mysqldump to add date to the
"-- Dump completed on ..." string at the end of output.
The --skip-dump-date switch supresses the output of date string
and uses short form of that commentary: "-- Dump completed".
--skip-comments or --compact switches disable the whole commentary
as usual.
The NAME_CONST function is required to work correctly with constants only.
When executed with functions that return types other than those returned by
Item::field_type (string, int, decimal, or real), the result gets cast to
one of those types. This cannot happen for constants.
Fixed by only allowing constants as arguments to NAME_CONST.
When calculating the result length of an integer DIV function
the number of decimals was used without checking the result type
first. Thus an uninitialized number of decimals was used for some
types. This caused an excessive amount of memory to be allocated
for the field's buffer and crashed the server.
Fixed by using the number of decimals only for data types that
can have decimals and thus have valid decimals number.
The optimizer takes different execution paths during EXPLAIN than SELECT,
this fix relates only to EXPLAIN, hence no behavior changes.
The test of sort keys for ORDER BY was prohibited from considering keys
that were mentioned in IGNORE KEYS FOR ORDER BY. This led to two
inconsistencies: One was that IGNORE INDEX FOR GROUP BY and
IGNORE INDEX FOR ORDER BY gave apparently different EXPLAINs; the latter
erroneously claimed to do filesort. The second inconsistency
is that the test of sort keys is called twice, finding a sort key the first
time but not the second time, leading to the mentioned filesort.
Fixed by making the test of sort keys consider all enabled
keys on the table. This test rejects keys that are not covering, and for
covering keys the hint should be ignored anyway.
When expanding a * in a USING/NATURAL join the check for table access
for both tables in the join was done using the grant information of the
first one.
Fixed by getting the grant information for the current table while
iterating through the columns of the join.
The `SELECT col FROM t WHERE col NOT IN (col, ...) GROUP BY col'
crashed in the range optimizer.
The get_func_mm_tree function has been modified to check the
Item_func_in::array field for the NULL value before using of that
value.
