Two problems here:
Problem 1:
While constructing the join columns list the optimizer does as follows:
1. Sets the join_using_fields/natural_join members of the right JOIN
operand.
2. Makes a "table reference" (TABLE_LIST) to parent the two tables.
3. Assigns the join_using_fields/is_natural_join of the wrapper table
using join_using_fields/natural_join of the rightmost table
4. Sets join_using_fields to NULL for the right JOIN operand.
5. Passes the parent table up to the same procedure on the upper
level.
Step 1 overrides the the join_using_fields that are set for a nested
join wrapping table in step 4.
Fixed by making a designated variable SELECT_LEX::prev_join_using to
pass the data from step 1 to step 4 without destroying the wrapping
table data.
Problem 2:
The optimizer checks for ambiguous columns while transforming
NATURAL JOIN/JOIN USING to JOIN ON. While doing that there was no
distinction between columns that are used in the generated join
condition (where ambiguity can be checked) and the other columns
(where ambiguity can be checked only when resolving references
coming from outside the JOIN construct itself).
Fixed by allowing the non-USING columns to be present in multiple
copies in both sides of the join and moving the ambiguity check
to the place where unqualified references to the join columns are
resolved (find_field_in_natural_join()).
The function that checks whether we can use keys for aggregates,
find_key_for_maxmin(), assumes that keys disabled by ALTER TABLE
... DISABLE KEYS are not in the set table->keys_in_use_for_query.
I.E., if a key is in this set, the optimizer assumes it is free to
use it.
The bug is that keys disabled with ALTER TABLE ... DISABLE KEYS still
appear in table->keys_in_use_for_query When the TABLE object has been
initialized with setup_tables(). Before setup_tables is called, however,
keys that are disabled in the aforementioned way are not included in
TABLE::keys_in_use_for_query.
The provided patch changes the code that updates keys_is_use_for_query so
that it assumes that keys_is_use_for_query already takes into account all
disabled keys, and generally all keys that should be used by the query.
Currently in the ONLY_FULL_GROUP_BY mode no hidden fields are allowed in the
select list. To ensure this each expression in the select list is checked
to be a constant, an aggregate function or to occur in the GROUP BY list.
The last two requirements are wrong and doesn't allow valid expressions like
"MAX(b) - MIN(b)" or "a + 1" in a query with grouping by a.
The correct check implemented by the patch will ensure that:
any field reference in the [sub]expressions of the select list
is under an aggregate function or
is mentioned as member of the group list or
is an outer reference or
is part of the select list element that coincide with a grouping element.
The Item_field objects now can contain the position of the select list
expression which they belong to. The position is saved during the
field's Item_field::fix_fields() call.
The non_agg_fields list for non-aggregated fields is added to the SELECT_LEX
class. The SELECT_LEX::cur_pos_in_select_list now contains the position in the
select list of the expression being currently fixed.
aliases ignored
When a column reference to a column in JOIN USING is resolved and a new
Item is created for this column the user defined name was lost.
This fix preserves the alias by setting the name of the new Item to the
original alias.
Corrected spelling in copyright text
Makefile.am:
Don't update the files from BitKeeper
Many files:
Removed "MySQL Finland AB & TCX DataKonsult AB" from copyright header
Adjusted year(s) in copyright header
Many files:
Added GPL copyright text
Removed files:
Docs/Support/colspec-fix.pl
Docs/Support/docbook-fixup.pl
Docs/Support/docbook-prefix.pl
Docs/Support/docbook-split
Docs/Support/make-docbook
Docs/Support/make-makefile
Docs/Support/test-make-manual
Docs/Support/test-make-manual-de
Docs/Support/xwf
Fixed compiler warnings (detected by VC++):
- Removed not used variables
- Added casts
- Fixed wrong assignments to bool
- Fixed wrong calls with bool arguments
- Added missing argument to store(longlong), which caused wrong store method to be called.
- Removed not used variables
- Changed some ulong parameters/variables to ulonglong (possible serious bug)
- Added casts to get rid of safe assignment from longlong to long (and similar)
- Added casts to function parameters
- Fixed signed/unsigned compares
- Added some constructores to structures
- Removed some not portable constructs
Better fix for bug Bug #21428 "skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"
(Added new parameter to net_clear() to define when we want the communication buffer to be emptied)
prepared statement and subquery.
When a field of a view from an outer select is resolved the find_field_in_view
function creates an Item_direct_view_ref object that references the
corresponding view underlying field. After that the view_ref is marked
as a dependent one. While resolving view underlying field it also get
marked as a dependent one due to current_select still points to the subselect.
Marking the view underlying field is wrong and lead to attaching conditions
to a wrong table and thus to the wrong result of the whole statement.
Now mark_select_range_as_dependent() function isn't called for fields from a
view underlying table.
Problems (appear only under some circumstances):
1. we get a reference to a deleted table searching in the
thd->handler_tables_hash in the mysql_ha_read().
2. DBUG_ASSERT(table->file->inited == handler::NONE); assert fails in the
close_thread_table().
Fix: end open index scans and table scans and remove references to the
tables from the handler tables hash. After this preparation it is safe
to close the tables. The close can no longer fail on open index/table
scans and the closed table will not be used again by handler functions.
Added missing DBUG_RETURN statements (in mysqldump.c)
Added missing enums
Fixed a lot of wrong DBUG_PRINT() statements, some of which could cause crashes
Removed usage of %lld and %p in printf strings as these are not portable or produces different results on different systems.
Fixed some possible fatal wrong arguments to printf() style functions
Initialized some not initialized variables
Fixed bug in stored procedure and continue handlers
(Fixes Bug#22150)
This is a performance issue for queries with subqueries evaluation
of which requires filesort.
Allocation of memory for the sort buffer at each evaluation of a
subquery may take a significant amount of time if the buffer is rather big.
With the fix we allocate the buffer at the first evaluation of the
subquery and reuse it at each subsequent evaluation.
account predicates that become sargable after reading const tables.
In some cases this resulted in choosing non-optimal execution plans.
Now info of such potentially saragable predicates is saved in
an array and after reading const tables we check whether this
predicates has become saragable.
