Item_in_subselect::pushed_cond_guards[] array is allocated only when
left_expr->maybe_null. And it is used (for row expressions) when
left_expr->element_index(i)->maybe_null.
For left_expr being a multi-column subquery, its maybe_null is
always false when the subquery doesn't use tables (see
Item_singlerow_subselect::fix_length_and_dec()
and subselect_single_select_engine::fix_length_and_dec()),
otherwise it's always true.
But row elements can be NULL regardless, so let's always allocate
pushed_cond_guards for multi-column subqueries, no matter whether
its maybe_null was forced to true or false.
CID 971836 (#1 of 1): Same on both sides (CONSTANT_EXPRESSION_RESULT)
pointless_expression: The expression val != end && val != end does not
accomplish anything because it evaluates to either of its identical
operands, val != end.
This is actually a legacy bug:
SQL_SELECT::test_quick_select() was called
with SQL_SELECT::head not set.
It looks like that this problem can be
reproduced only on queries with ORDER BY
that use IN predicates converted to semi-joins.
This patch corrects the fix for bug mdev-7599.
When the min/max optimization of the function
opt_sum_query() optimizes away all tables of
a subquery it should not ever be rolled back.
If the optimizer chose an execution plan where
a semi-join nest were materialized and the
result of materialization was scanned to access
other tables by ref access it could build a key
over columns of the tables from the nest that
were actually inaccessible.
The patch performs a proper check whether a key
that uses columns of the tables from a materialized
semi-join nest can be employed to access outer tables.
Problem:-
This crash happens because logged stmt is quite big and while writing
Annotate_rows_log_event it throws EFBIG error but we ignore this error
and do not call cache_data->set_incident().
Solution:-
When we normally write Binlog_log_event we check for error EFBIG, but we did
do this for Annotate_rows_log_event. We check for this error and call
cache_data->set_incident() accordingly.
# Conflicts:
# sql/log.cc
This is another correction of the patch for bug mdev-12670.
If a derived table is merged into a select with STRAIGHT_JOIN
modifier all IN subquery predicates contained in the
specification of the derived table cannot be subject to
conversion to semi-joins.
This patch is a correction of the patch for bug mdev-12670.
With the current code handling semi-joins the following must
be taken into account.
Conversion of an IN subquery predicate into semi-join
has to be blocked if the predicate occurs:
(a) in the ON expression of an outer join
(b) in the ON expression of an inner join embedded directly
or indirectly in the inner nest of an outer join.
The patch for mdev-12670 blocked conversion to semi-joins only
in the case (a), but not in the case (b). This patch blocks
the conversion in both cases.
When an IN subquery predicate was converted to a semi-join that were
materialized and the result of the materialization happened to be
the last in the execution plan then any conjunctive condition with RAND()
turned out to be lost.
Fixed by attaching this condition to the last top base table.
At some conditions the function opt_sum_query() can apply MIN/MAX
optimizations to to Item_sum objects of a select These optimizations
becomes invalid if this select is the subquery of an IN subquery
predicate that is converted to a EXISTS subquery. Thus in this case
the MIX/MAX optimizations that have been applied in opt_sum_query()
must be rolled back.
This bug appeared in 5.3 when the code for the cost base choice between
materialization and in-to-exists transformation of non-correlated
IN subqueries was introduced. Before this code in-to-exists
transformations were always performed before the call of opt_sum_query().
The code that blocked conversion of a IN subselect pedicate to a semi-join
if it occurred in the ON expression of an outer join did not do it correctly.
As a result, the conversion was blocked for IN subselect predicates
encountered in ON expressions of INNER joins or in WHERE conditions
of mergeable views / derived tables. This patch fixes this problem.
This patch corrects the fix for the bug mdev-10693.
It is critical for the function get_best_combination() not to call
create_ref_for_key() for constant tables.
This bug could manifest itself only in multi-table subqueries where
one of the tables is accessed by a constant primary key.
/home/travis/build/MariaDB/server/extra/mysqld_safe_helper.c:62:21: warning: too many arguments in call to 'do_usage'
do_usage(argv[0]);
~~~~~~~~ ^
1 warning generated.
The code that chooses between materialization of a non-correlated
IN subquery and its transformation into an EXISTS correlated
subquery assumes that the execution plan for the outer select
has been already built. However it was not always so if subqueries
occurred in the expressions used for ref access to tables of
the outer select. A call of the function create_ref_for_key() in
get_best_combination() could trigger a premature execution of
the above mentioned code when the execution plan structures for
the outer select were not fully built. This could cause a crash
of the server.
The fix postpones the calls of create_ref_for_key() until the
structures for the execution plan is fully built.
The motivation for this is that Perl is moving towards not having
current directory ./ in @INC by default. This is causing
mysql-test-run.pl to fail in latest Debian Unstable:
https://lists.debian.org/debian-devel-announce/2016/08/msg00013.html
However, we have `use "lib"`, there is no need for current directory
in @INC, except for a gross hack. In mtr_cases.pm, there is a
`require "mtr_misc.pl"`, which hides mtr_misc.pl away in mtr_cases
namespace. And things only work because mysql-test-run.pl loads it
with a different name, `require "lib/mtr_misc.pl"`! (Perl will
`require` only once for each unique filename).
Fix this by only using `require` in main program, and referencing
functions with :: scope from other namespaces. For multi-use in
different namespaces, proper `use` modules should be used.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
