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.
to behave well on 5.0 tables (well now you can't use tables from 4.1
and 5.0 with 4.0 because former use utf8, but still it is nice to have
similar code in acl_init() and replace_user_table()).
This also will make such GRANTs working in 5.0 (they are broken now).
STR_TO_DATE() function if there is another format specifier after %f
in format string". Also small cleanup of STR_TO_DATE() implementation.
(After review version.)
Add a comment that no InnoDB table lock is now acquired in LOCK TABLES if AUTOCOMMIT=1. This helps to avoid deadlocks when porting old MyISAM applications to InnoDB.
If AUTOCOMMIT=1, do not acquire an InnoDB table lock in LOCK TABLES; this makes porting of old MyISAM applications to InnoDB easier, since in that mode InnoDB table locks caused deadlocks very easily
Fix InnoDB bug: on HP-UX, with a 32-bit binary, InnoDB was only able to read or write <= 2 GB files; the reason was that InnoDB treated the return value of lseek() as a 32-bit integer; lseek was used on HP-UX-11 as a replacement for pread() and pwrite() because HAVE_BROKEN_PREAD was defined on that platform
