When inserting into a join-based view the update fields from the ON DUPLICATE
KEY UPDATE wasn't checked to be from the table being inserted into and were
silently ignored.
The new check_view_single_update() function is added to check that
insert/update fields are being from the same single table of the view.
After fix for bug#21798 JOIN stores the pointer to the buffer for sorting
fields. It is used while sorting for grouping and for ordering. If ORDER BY
clause has more elements then the GROUP BY clause then a memory overrun occurs.
Now the length of the ORDER BY list is always passed to the
make_unireg_sortorder() function and it allocates buffer big enough to be
used for bigger list.
UNION over correlated and uncorrelated SELECTS.
In such subqueries each uncorrelated SELECT should be considered as
uncacheable. Otherwise join_free is called for it and in many cases
it causes some problems.
crashes server
Check for null value is reliable only after calling some of the
val_xxx() methods. If the val_xxx() method is not called
the null_value flag will be set only for certain types of NULL
values (like SQL constant NULLs for example).
This caused a crash while trying to dereference a NULL pointer
that is returned by val_str() for NULL values.
Fixed by swapping the order of val_xxx() and null_value check.
when they contain the '!' operator.
Added an implementation for the method Item_func_not::print.
The method encloses any NOT expression into extra parentheses to avoid
incorrect stored representations of views that use the '!' operators.
Without this change when a view was created that contained
the expression !0*5 its stored representation contained not this
expression but rather the expression not(0)*5 .
The operator '!' is of a higher precedence than '*', while NOT is
of a lower precedence than '*'. That's why the expression !0*5
is interpreted as not(0)*5, while the expression not(0)*5 is interpreted
as not((0)*5) unless sql_mode is set to HIGH_NOT_PRECEDENCE.
Now we translate !0*5 into (not(0))*5.
The optimizer needs to evaluate whether predicates are better
evaluated using an index. IN is one such predicate.
To qualify an IN predicate must involve a field of the index
on the left and constant arguments on the right.
However whether an expression is a constant can be determined only
by knowing the preceding tables in the join order.
Assuming that only IN predicates with expressions on the right that
are constant for the whole query qualify limits the scope of
possible optimizations of the IN predicate (more specifically it
doesn't allow the "Range checked for each record" optimization for
such an IN predicate.
Fixed by not pre-determining the optimizability of the IN predicate
in the case when all right IN operands are not SQL constant expressions
of untouched rows in full table scans".
SELECT ... FOR UPDATE/LOCK IN SHARE MODE statements as well as
UPDATE/DELETE statements which were executed using full table
scan were not releasing locks on rows which didn't satisfy
WHERE condition.
This bug surfaced in 5.0 and affected NDB tables. (InnoDB tables
intentionally don't support such unlocking in default mode).
This problem occured because code implementing join didn't call
handler::unlock_row() for rows which didn't satisfy part of condition
attached to this particular table/level of nested loop. So we solve
the problem adding this call.
Note that we already had this call in place in 4.1 but it was lost
(actually not quite correctly placed) when we have introduced nested
joins.
Also note that additional QA should be requested once this patch is
pushed as interaction between handler::unlock_row() and many recent
MySQL features such as subqueries, unions, views is not tested enough.
for queries using 'range checked for each record'.
The problem was fixed in 5.0 by the patch for bug 12291.
This patch down-ported the corresponding code from 5.0 into
QUICK_SELECT::init() and added a new test case.
in a select list.
The objects of the Item_trigger_field class inherited the implementations
of the methods copy_or_same, get_tmp_table_item and get_tmp_table_field
from the class Item_field while they rather should have used the default
implementations defined for the base class Item.
It could cause catastrophic problems for triggers that used SELECTs
with select list containing trigger fields such as NEW.<table column>
under DISTINCT.
