Remove TMP_TABLE_PARAM::copy_funcs_it. TMP_TABLE_PARAM is a member of JOIN which is
copied via memcpy, and List_iterator_fast TMP_TABLE_PARAM::copy_funcs_it ends up
pointing to the wrong List.
Added test cases for bug #7351.
item_cmpfunc.cc:
Fixed bug #7351: incorrect result for a query with a
subquery returning empty set.
If in the predicate v IN (SELECT a FROM t WHERE cond)
v is null, then the result of the predicate is either
INKNOWN or FALSE. It is FALSE if the subquery returns
an empty set.
item_subselect.cc:
Fixed bug #7351: incorrect result for a query with a
subquery returning empty set.
The problem was due to not a quite legal transformation
for 'IN' subqueries. A subquery containing a predicate
of the form
v IN (SELECT a FROM t WHERE cond)
was transformed into
EXISTS(SELECT a FROM t WHERE cond AND (a=v OR a IS NULL)).
Yet, this transformation is valid only if v is not null.
If v is null, then, in the case when
(SELECT a FROM t WHERE cond) returns an empty set the value
of the predicate is FALSE, otherwise the result of the
predicate is INKNOWN.
The fix resolves this problem by changing the result
of the transformation to
EXISTS(SELECT a FROM t WHERE cond AND (v IS NULL OR (a=v OR a IS NULL)))
in the case when v is nullable.
The new transformation prevents applying the lookup
optimization for IN subqueries. To make it still
applicable we have to introduce guarded access methods.
Renamed HA_VAR_LENGTH to HA_VAR_LENGTH_PART
Renamed in all files FIELD_TYPE_STRING and FIELD_TYPE_VAR_STRING to MYSQL_TYPE_STRING and MYSQL_TYPE_VAR_STRING to make it easy to catch all possible errors
Added support for VARCHAR KEYS to heap
Removed support for ISAM
Now only long VARCHAR columns are changed to TEXT on demand (not CHAR)
Internal temporary files can now use fixed length tables if the used VARCHAR columns are short
results." a.k.a. "Proper cleanup of subqueries is missing for SET and DO
statements". (Version #2 with after-review fixes).
To perform proper cleanup for statements that can contain subqueries
but don't have main select we must call free_undelaid_joins().
FOUND is not a reserved keyword anymore
Added Item_field::set_no_const_sub() to be able to mark fields that can't be substituted
Added 'simple_select' method to be able to quickly determinate if a select_result is a normal SELECT
Note that the 5.0 tree is not yet up to date: Sanja will have to fix multi-update-locks for this merge to be complete
improved mechanisn of detection posibility to be NULL for single row queries
switched off substitution optimisation for single row subqueries in PS due to problem in resolving substituted expressions
(changes to make subselects test working with PS protocol)
prepared statements when LIMIT is used" and post-review comments.
The fix changes the approach we calculate the need for ORDER BY
in UNION: the previous was not PS friendly, as it damaged SELECT_LEX
options in case of single select.
Added the code processing on expressions for applying
multiple equalities.
sql_select.cc:
Post-merge fixes for Item_equal patch.
Added the code processing on expressions for applying
multiple equalities.
Many files:
Post-merge fixes for Item_equal patch.
item_cmpfunc.cc:
Post-merge fixes for Item_equal patch.
Fixed a problem when an equality field=const cannot be applied to
the predicate P(field,c) for constant propagation as a conversion
of field is needed.
item.h, item.cc:
Fixed a problem when an equality field=const cannot be applied to
the predicate P(field,c) for constant propagation as a conversion
of field is needed.
