- Don't pull out a table out of a semi-join if it is on the inner side of an outer join.
- Make join->sort_by_table= get_sort_by_table(...) call after const table detection
is done. That way, the value of join->sort_by_table will match the actual execution.
Which will allow the code in setup_semijoin_dups_elimination() (search for
"Make sure that possible sorting of rows from the head table is not to be employed."
to see that "Using filesort" is going to be used together with Duplicate Elimination (
and change it to Using temporary + Using filesort)
- make_join_readinfo() has the code that forces use of "Using temporary;
Using filesort" when join buffering is in use.
That code didn't handle all cases, in particular it didn't hande the case
where ORDER BY originally has tables from multiple columns, but the
optimizer eventually figures out that doing filesort() on one table
will be sufficient. Adjusted the code to handle that case.
Apply fix suggested by Igor:
- When eliminate_item_equal() generates pair-wise equalities from a
multi-equality, do generate a "bridge" equality between the first
field inside SJM nest and the field that's first in the overall multi-equality.
When setting Item_func_not_all::test_sum_item or Item_func_not_all::test_sub_item,
reset the other one to NULL - they can never be set both. When a PS is reexecuted,
different executions might be optimized differently and a wrong test_su*_item
might stay set from the previous execution.
- MIN/MAX optimizer does a check whether a "field CMP const" comparison uses a constant
that's longer than the field it is compared to. Make this check only for string columns,
also compare character lengths, not byte lengths.
1. Transformation of row IN subquery made the same as single value.
2. replace_where_subcondition() made working on several layers of OR/AND because it called on expression before fix_fields().
(and valgrind warnings)
* move thd userstat initialization to the same function
that was adding thd userstat to global counters.
* initialize thd->start_bytes_received in THD::init
(when thd->userstat_running is set)
Singular Item_equal support added.
The problem was that during constant table substitution Item_equal become containing only one constant which was not supported internally.
The loop in the binary search in remove_status_vars() was
incorrectly implemented and could continue infinitely in some cases.
Rewrote the binary search code.
An addition to fix for MDEV-5205, fixes server crash on shutdown.
Thread groups are destroyed asynchronously, that is kill server
thread sends shutdown request to all thread groups without waiting
for compeltion.
It means all_groups array must not be freed until all thread groups
are down. This patch suggests that all_groups is freed when last
thread group is destroyed.
Note 1: threadpool code doesn't surround atomic ops with atomic locks,
thus no locks for shutdown_group_count.
Note 2: this patch preserves old behaviour, but we may need to wait
until all thread groups are down before returning from tp_end().
- thread_pool_size command line option upper limit increased to 100 000
(same as for max_connections)
- thread_pool_size system variable upper limit is maximum of 128 or
the value given at command line
- thread groups are now allocated dynamically
Different limit for command line option and system variable was done to
avoid additional mutex for all_groups and threadpool_max_size.
There was 2 problems:
1) coping/moving of the same type (usually casting) as sizeof() (solved in different ways depends on the cause);
2) using 'const' in SSL_CTX::getVerifyCallback() which return object (not reference) and so copy of the object will be created and 'const' has no sens.
Analysis:
st_select_lex_unit::prepare() computes can_skip_order_by as TRUE.
As a result join->prepare() gets called with order == NULL, and
doesn't do name resolution for the inner ORDER clause. Due to this
the prepare phase doesn't detect that the query references non-exiting
function and field.
Later join->optimize() calls update_used_tables() for a non-resolved
Item_field, which understandably has no Field object. This call results
in a crash.
Solution:
Resolve unnecessary ORDER BY clauses to detect if they reference non-exising
objects. Then remove such clauses from the JOIN object.
- Backport MySQL's fix: do set ha_partition::m_pkey_is_clustered for ha_partition
objects created with handler->clone() call.
- Also, include a testcase.
