ORDER BY computed col
GROUP BY implies ORDER BY in the MySQL dialect of SQL. Therefore, when an
index on the first table in the query is used, and that index satisfies
ordering according to the GROUP BY clause, the query optimizer estimates the
number of tuples that need to be read from this index. If there is a LIMIT
clause, table statistics on tables following this 'sort table' are employed.
There may be a separate ORDER BY clause however, which mandates reading the
whole 'sort table' anyway. But the previous estimate was left untouched.
Fixed by removing the estimate from EXPLAIN output if GROUP BY is used in
conjunction with an ORDER BY clause that mandates using a temporary table.
inited==INDEX
When an error occurs while sending the data in a temporary table there was no
cleanup performed. This caused a failed assertion in the case when different
access methods were used for populating the table vs. retrieving the data from
the table if IGNORE was specified and sql_safe_updates = 0. In this case
execution continues, but the handler expects to continue with the access
method used for row retrieval.
Fixed by doing the cleanup even if errors occur.
Bug#46754: 'rows' field doesn't reflect partition pruning
The EXPLAIN's result in 'rows' field
was evaluated to number of rows when the table was opened
(not from the table cache) and only the partitions left
after pruning was updated with its correct number
of rows.
The evaluation of the 'rows' field was using handler::records()
which is a potentially expensive call, and ignores the partitioning
pruning.
The fix was to use the handlers stats.records after updating it
with ::info(HA_STATUS_VARIABLE) instead.
mysql-test/r/partition_pruning.result:
updated result
mysql-test/t/partition_pruning.test:
Added test.
sql/sql_select.cc:
Use ::info + stats.records instead of ::records().
After fix for bug 39653 the shortest available secondary index was used for
full table scan. Primary clustered key was used only if no secondary index
can be used. However, when chosen secondary index includes all fields of the
table being scanned it's better to use primary index since the amount of
data to scan is the same but the primary index is clustered.
Now the find_shortest_key function takes this into account.
mysql-test/suite/innodb/r/innodb_mysql.result:
Added a test case for the bug#55656.
mysql-test/suite/innodb/t/innodb_mysql.test:
Added a test case for the bug#55656.
sql/sql_select.cc:
Bug #55656: mysqldump can be slower after bug #39653 fix.
The find_shortest_key function now prefers clustered primary key
if found secondary key includes all fields of the table.
The server was not checking for errors generated during
the execution of Item::val_xxx() methods when copying
data to the group, order, or distinct temp table's row.
Fixed by extending the copy_funcs() to return an error
code and by checking for that error code on the places
copy_funcs() is called.
Test case added.
INSERT IGNORE ... SELECT ... UNION SELECT ...
This assert was triggered by INSERT IGNORE ... SELECT. The assert checks that a
statement either sends OK or an error to the client. If the bug was triggered
on release builds, it caused OK to be sent to the client instead of the correct
error message (in this case ER_FIELD_SPECIFIED_TWICE).
The reason the assert was triggered, was that lex->no_error was set to TRUE
during JOIN::optimize() because of IGNORE. This causes all errors to be ignored.
However, not all errors can be ignored. Some, such as ER_FIELD_SPECIFIED_TWICE
will cause the INSERT to fail no matter what. But since lex->no_error was set,
the critical errors were ignored, the INSERT failed and neither OK nor the
error message was sent to the client.
This patch fixes the problem by temporarily turning off lex->no_error in
places where errors cannot be ignored during processing of INSERT ... SELECT.
Test case added to insert.test.
This assert checks that the server does not try to send OK to the
client if there has been some error during processing. This is done
to make sure that the error is in fact sent to the client.
The problem was that view errors during processing of WHERE conditions
in UPDATE statements where not detected by the update code. It therefore
tried to send OK to the client, triggering the assert.
The bug was only noticeable in debug builds.
This patch fixes the problem by making sure that the update code
checks for errors during condition processing and acts accordingly.
The problem there is that HAVING condition evaluates const
parts of condition despite the condition has references
on aggregate functions. Table t1 became const tables
after make_join_statistics and table1.pk = 1, HAVING is
transformed into MAX(1) < 7 and taken away from HAVING.
The fix is to skip evaluation of HAVING conts parts if
HAVING condition has references on aggregate functions.
mysql-test/r/having.result:
test case
mysql-test/t/having.test:
test case
sql/sql_select.cc:
skip evaluation of HAVING conts parts if
HAVING condition has references on aggregate functions.
The problem is that QUICK_SELECT_DESC behaviour depends
on used_key_parts value which can be bigger than selected
best_key_parts value if an engine supports clustered key.
But used_key_parts is overwritten with best_key_parts
value that prevents from correct selection of index
access method. The fix is to preserve used_key_parts
value for further use in QUICK_SELECT_DESC.
mysql-test/r/innodb_mysql.result:
test case
mysql-test/t/innodb_mysql.test:
test case
sql/sql_select.cc:
preserve used_key_parts value for further use in QUICK_SELECT_DESC
file .\filesort.cc, line 149 (part II)
Problem: the server didn't disregard sort order
for some zero length tuples.
Fix: skip sort order in such a case
(zero length NOT NULL string functions).
mysql-test/r/select.result:
Fix for bug #54459: Assertion failed: param.sort_length,
file .\filesort.cc, line 149 (part II)
- test result.
mysql-test/t/select.test:
Fix for bug #54459: Assertion failed: param.sort_length,
file .\filesort.cc, line 149 (part II)
- test case.
sql/sql_select.cc:
Fix for bug #54459: Assertion failed: param.sort_length,
file .\filesort.cc, line 149 (part II)
- disregard sort order for zero length NOT NULL string functions
along with zero length NOT NULL fields.
strict aliasing violations.
One somewhat major source of strict-aliasing violations and
related warnings is the SQL_LIST structure. For example,
consider its member function `link_in_list` which takes
a pointer to pointer of type T (any type) as a pointer to
pointer to unsigned char. Dereferencing this pointer, which
is done to reset the next field, violates strict-aliasing
rules and might cause problems for surrounding code that
uses the next field of the object being added to the list.
The solution is to use templates to parametrize the SQL_LIST
structure in order to deference the pointers with compatible
types. As a side bonus, it becomes possible to remove quite
a few casts related to acessing data members of SQL_LIST.
sql/handler.h:
Use the appropriate template type argument.
sql/item.cc:
Remove now-unnecessary cast.
sql/item_subselect.cc:
Remove now-unnecessary casts.
sql/item_sum.cc:
Use the appropriate template type argument.
Remove now-unnecessary cast.
sql/mysql_priv.h:
Move SQL_LIST structure to sql_list.h
Use the appropriate template type argument.
sql/sp.cc:
Remove now-unnecessary casts.
sql/sql_delete.cc:
Use the appropriate template type argument.
Remove now-unnecessary casts.
sql/sql_derived.cc:
Remove now-unnecessary casts.
sql/sql_lex.cc:
Remove now-unnecessary casts.
sql/sql_lex.h:
SQL_LIST now takes a template type argument which must
match the type of the elements of the list. Use forward
declaration when the type is not available, it is used
in pointers anyway.
sql/sql_list.h:
Rename SQL_LIST to SQL_I_List. The template parameter is
the type of object that is stored in the list.
sql/sql_olap.cc:
Remove now-unnecessary casts.
sql/sql_parse.cc:
Remove now-unnecessary casts.
sql/sql_prepare.cc:
Remove now-unnecessary casts.
sql/sql_select.cc:
Remove now-unnecessary casts.
sql/sql_show.cc:
Remove now-unnecessary casts.
sql/sql_table.cc:
Remove now-unnecessary casts.
sql/sql_trigger.cc:
Remove now-unnecessary casts.
sql/sql_union.cc:
Remove now-unnecessary casts.
sql/sql_update.cc:
Remove now-unnecessary casts.
sql/sql_view.cc:
Remove now-unnecessary casts.
sql/sql_yacc.yy:
Remove now-unnecessary casts.
storage/myisammrg/ha_myisammrg.cc:
Remove now-unnecessary casts.
There are two problems:
1. In simplify_joins function we calculate table dependencies. If STRAIGHT_JOIN hint
is used for whole SELECT we do not count it and as result some dependendecies
might be lost. It leads to incorrect table order which is returned by
join_tab_cmp_straight() function.
2. make_join_statistics() calculate the transitive closure for relations a particular
JOIN_TAB is 'dependent on'.
We aggregate the dependent table_map of a JOIN_TAB by adding dependencies from other
tables which we depend on. However, this may also cause new dependencies to be
available after we have completed processing a certain JOIN_TAB.
Both these problems affect condition pushdown and as result condition might be pushed
into wrong table which leads to crash or even omitted which leads to wrong result.
The fix:
1. Use modified 'transitive closure' algorithm provided by Ole John Aske
2. Update table dependences in simplify_joins according to
global STRAIGHT_JOIN hint.
Note: the patch also fixes bugs 46091 & 51492
mysql-test/r/join_outer.result:
test case
mysql-test/t/join_outer.test:
test case
sql/sql_select.cc:
1. Use modified 'transitive closure' algorithm provided by Ole John Aske
2. Update table dependences in simplify_joins according to
global STRAIGHT_JOIN hint.
The fix actually reverts the change introduced
by the patch for bug 51494.
The fact is that patches for bugs 52177&48419
fix bugs 51194&50575 as well.
mysql-test/r/innodb_mysql.result:
test case
mysql-test/t/innodb_mysql.test:
test case
sql/sql_select.cc:
reverted wrong fix for bug 51494
greedy_search optimizer_search_depth=0
The algorithm inside restore_prev_nj_state failed to
properly update the counters within the NESTED_JOIN
tree. The counter was decremented each time a table in the
node was removed from the QEP, the correct thing to do being
only to decrement it when the last table in the child node
was removed from the plan. This lead to node counters
getting negative values and the plan thus appeared
impossible. An assertion caught this.
Fixed by not recursing up the tree unless the last table in
the join nest node is removed from the plan
WHERE predicates containing references to empty tables in a
subquery were handled incorrectly by the optimizer when
executing EXPLAIN. As a result, the optimizer could try to
evaluate such predicates rather than just stop with
"Impossible WHERE noticed after reading const tables" as
it would do in a non-subquery case. This led to valgrind
errors and crashes.
Fixed the code checking the above condition so that subqueries
are not excluded and hence are handled in the same way as top
level SELECTs.
mysql-test/r/explain.result:
Added a test case for bug #48419.
mysql-test/r/ps.result:
Updated test results to take the new (and more correct)
"Extra" comments in execution plans.
mysql-test/t/explain.test:
Added a test case for bug #48419.
sql/sql_select.cc:
There is no point in excluding subqueries from checking
for identically false WHERE conditions.
The problem was in an incorrect debug assertion. The expression
used in the failing assertion states that when finding
references matching ORDER BY expressions, there can be only one
reference to a single table. But that does not make any sense,
all test cases for this bug are valid examples with multiple
identical WHERE expressions referencing the same table which
are also present in the ORDER BY list.
Fixed by removing the failing assertion. We also have to take
care of the 'found' counter so that we count multiple
references only once. We rely on this fact later in
eq_ref_table().
mysql-test/r/join.result:
Added a test case for bug #50335.
mysql-test/t/join.test:
Added a test case for bug #50335.
sql/sql_select.cc:
Removing the assertion in eq_ref_table() as it does not make
any sense. We also have to take care of the 'found' counter so
that we count multiple references only once. We rely on this
fact later in eq_ref_table().
union...order by (select... where...)
The problem is mysql is trying to materialize and
cache the scalar sub-queries at JOIN::optimize
even for EXPLAIN where the number of columns is
totally different from what's expected.
Fixed by not executing the scalar subqueries
for EXPLAIN.
The problem is that we can not use make_cond_for_table().
This function relies on used_tables() condition
which is not set properly for subqueries.
As result subquery is not filtered out.
The fix is to use remove_eq_conds() function instead
of make_cond_for_table() func. 'remove_eq_conds()'
algorithm relies on const_item() value and it allows
to handle subqueries in right way.
mysql-test/r/having.result:
test case
mysql-test/t/having.test:
test case
sql/sql_select.cc:
The fix is to use remove_eq_conds() function instead
of make_cond_for_table() function.
The crash is the result of an attempt made by JOIN::optimize to evaluate
the WHERE condition when no records have been actually read.
The fix is to remove erroneous 'outer_join' variable check.
mysql-test/r/join.result:
test result
mysql-test/t/join.test:
test case
sql/sql_select.cc:
removed erroneous 'outer_join' variable check.
The crash happens because greedy_serach
can not determine best plan due to
wrong inner table dependences. These
dependences affects join table sorting
which performs before greedy_search starting.
In our case table which has real 'no dependences'
should be put on top of the list but it does not
happen as inner tables have no dependences as well.
The fix is to exclude RAND_TABLE_BIT mask from
condition which checks if table dependences
should be updated.
mysql-test/r/join.result:
test result
mysql-test/t/join.test:
test case
sql/sql_select.cc:
RAND_TABLE_BIT mask should not be counted as it
prevents update of inner table dependences.
For example it might happen if RAND() function
is used in JOIN ON clause.
The problem is that when we make conditon for
grouped result const part of condition is cut off.
It happens because some parts of 'having' condition
which refer to outer join become const after
make_join_statistics. These parts may be lost
during further having condition transformation
in JOIN::exec. The fix is adding 'having'
condition check for const tables after
make_join_statistics is performed.
mysql-test/r/having.result:
test case
mysql-test/t/having.test:
test result
sql/sql_select.cc:
added 'having' condition check for const tables
after make_join_statistics is performed.
The crash happens because of discrepancy between values of
conts_tables and join->const_table_map(make_join_statisctics).
Calculation of conts_tables used condition with
HA_STATS_RECORDS_IS_EXACT flag check. Calculation of
join->const_table_map does not use this flag check.
In case of MERGE table without union with index
the table does not become const table and
thus join_read_const_table() is not called
for the table. join->const_table_map supposes
this table is const and later in make_join_select
this table is used for making&calculation const
condition. As table record buffer is not populated
it leads to crash.
The fix is adding a check if an engine supports
HA_STATS_RECORDS_IS_EXACT flag before updating
join->const_table_map.
mysql-test/r/merge.result:
test result
mysql-test/t/merge.test:
test case
sql/sql_select.cc:
adding a check if an engine supports
HA_STATS_RECORDS_IS_EXACT flag before updating
join->const_table_map.
SunStudio
SunStudio compilers of late warn about methods that might hide
methods in base classes due to the use of overloading combined
with overriding. SunStudio also warns about variables defined
in local socpe or method arguments that have the same name as
a member attribute of the class.
This patch renames methods that might hide base class methods,
to make it easier both for humans and compilers to see what is
actually called. It also renames variables in local scope.
sql/field.cc:
Local scope variable or method argument same as class
attribute.
sql/item_cmpfunc.cc:
Local scope variable or method argument same as class
attribute.
sql/item_create.cc:
Renaming base class create() to create_func().
sql/item_create.h:
Renaming base class create() to create_func().
sql/protocol.cc:
Local scope variable or method argument same as class
attribute.
sql/sql_profile.cc:
Local scope variable or method argument same as class
attribute.
sql/sql_select.cc:
Local scope variable or method argument same as class
attribute.
sql/sql_yacc.yy:
Renaming base class create() to create_func().
storage/federated/ha_federated.cc:
Local scope variable or method argument same as class
attribute.
storage/myisammrg/ha_myisammrg.cc:
Local scope variable or method argument same as class
attribute.
The problem is that not all column names retrieved from a SELECT
statement can be used as view column names due to length and format
restrictions. The server failed to properly check the conformity
of those automatically generated column names before storing the
final view definition on disk.
Since columns retrieved from a SELECT statement can be anything
ranging from functions to constants values of any format and length,
the solution is to rewrite to a pre-defined format any names that
are not acceptable as a view column name.
The name is rewritten to "Name_exp_%u" where %u translates to the
position of the column. To avoid this conversion scheme, define
explict names for the view columns via the column_list clause.
Also, aliases are now only generated for top level statements.
mysql-test/include/view_alias.inc:
Add test case for Bug#40277
mysql-test/r/compare.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/group_by.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/ps.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect3.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/type_datetime.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/union.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/view.result:
Add test case result for Bug#40277
mysql-test/r/view_alias.result:
Add test case result for Bug#40277
mysql-test/t/view_alias.test:
Add test case for Bug#40277
sql/sql_view.cc:
Check if auto generated column names are conforming. Also, the
make_unique_view_field_name function is not used as it uses the
original name to construct a new one, which does not work if the
name is invalid.
consider clustered primary keys
Choosing a shortest index for the covering index scan,
the optimizer ignored the fact, that the clustered primary
key read involves whole table data.
The find_shortest_key function has been modified to
take into account that fact that a clustered PK has a
longest key of possible covering indices.
mysql-test/r/innodb_mysql.result:
Test case for bug #39653.
mysql-test/t/innodb_mysql.test:
Test case for bug #39653.
sql/sql_select.cc:
Bug #39653: find_shortest_key in sql_select.cc does not
consider clustered primary keys
The find_shortest_key function has been modified to
take into account that fact that a clustered PK has a
longest key of possible covering indices.
The problem is that cond->fix_fields(thd, 0) breaks
condition(cuts off 'having'). The reason of that is
that NULL valued Item pointer is present in the
middle of Item list and it breaks the Item processing
loop.
mysql-test/r/having.result:
test case
mysql-test/t/having.test:
test case
sql/item_cmpfunc.h:
added ASSERT to make sure that we do not add NULL valued Item pointer
sql/sql_select.cc:
skip adding an item to condition if Item pointer is NULL.
skip adding a list to condition if this list is empty.
performance degradation.
Filesort + join cache combination is preferred to full index scan because it
is usually faster. But it's not the case when the index is clustered one.
Now test_if_skip_sort_order function prefers filesort only if index isn't
clustered.
mysql-test/r/innodb_mysql.result:
Added a test case for the bug#50843.
mysql-test/t/innodb_mysql.test:
Added a test case for the bug#50843.
sql/sql_select.cc:
Bug#50843: Filesort used instead of clustered index led to
performance degradation.
Now test_if_skip_sort_order function prefers filesort only if index isn't
clustered.
The problem was in an incorrect debug assertion. The expression
used in the failing assertion states that when finding
references matching ORDER BY expressions, there can be only one
reference to a single table. But that does not make any sense,
all test cases for this bug are valid examples with multiple
identical WHERE expressions referencing the same table which
are also present in the ORDER BY list.
Fixed by removing the failing assertion. We also have to take
care of the 'found' counter so that we count multiple
references only once. We rely on this fact later in
eq_ref_table().
mysql-test/r/join.result:
Added a test case for bug #50335.
mysql-test/t/join.test:
Added a test case for bug #50335.
sql/sql_select.cc:
Removing the assertion in eq_ref_table() as it does not make
any sense. We also have to take care of the 'found' counter so
that we count multiple references only once. We rely on this
fact later in eq_ref_table().
The problem is that during temporary table creation uneven bits
are not taken into account for hidden fields. It leads to incorrect
calculation&allocation of null bytes size for table record. And
if grouped value is null we set wrong bit for this value(see end_update()).
Fixed by adding separate calculation of uneven bit for hidden fields.
mysql-test/r/type_bit.result:
test case
mysql-test/t/type_bit.test:
test case
sql/sql_select.cc:
added separate calculation of uneven bit for hidden fields
column is used for ORDER BY
Problem: filesort isn't meant for null length sort data
(e.g. char(0)), that leads to a server crash.
Fix: disregard sort order if sort data record length is 0 (nothing
to sort).
mysql-test/r/select.result:
Fix for bug#49897: crash in ptr_compare when char(0) NOT NULL
column is used for ORDER BY
- test result.
mysql-test/t/select.test:
Fix for bug#49897: crash in ptr_compare when char(0) NOT NULL
column is used for ORDER BY
- test case.
sql/filesort.cc:
Fix for bug#49897: crash in ptr_compare when char(0) NOT NULL
column is used for ORDER BY
- assert added as filesort cannot handle null length sort data.
sql/sql_select.cc:
Fix for bug#49897: crash in ptr_compare when char(0) NOT NULL
column is used for ORDER BY
- don't sort null length data e.g. in case of ORDER BY CHAR(0).
The problem becomes apparent only if HAVE_purify is undefined.
It related to the part of code placed in open_table_from_share() fuction
where we initialize record buffer only if HAVE_purify is enabled.
So in case of HAVE_purify=OFF record buffer is not initialized
on open table stage.
Next we read key, find NULL value and update appropriate null bit
but do not update record buffer. After that the record is stored
in the join cache(store_record_in_cache). For CHAR fields we
strip trailing spaces and in our case this procedure uses
uninitialized record buffer.
The fix is to skip stripping space procedure in case of null values
for CHAR fields(partially based on 6.0 JOIN_CACHE implementation).
mysql-test/r/join.result:
test case
mysql-test/t/join.test:
test case
sql/field.cc:
code updated according to new CACHE_FIELD struct
sql/sql_select.cc:
code updated according to new CACHE_FIELD struct
sql/sql_select.h:
CACHE_FIELD struct:
added new fields: Field *field, uint type;
removed fields: Field_blob *blob_field, bool strip;
Queries optimized with GROUP_MIN_MAX didn't cleanup KEYREAD
optimization properly. As a result subsequent queries may
return incomplete rows (fields are initialized to default
values).
mysql-test/r/group_min_max.result:
A test case for BUG#49902.
mysql-test/t/group_min_max.test:
A test case for BUG#49902.
sql/opt_range.cc:
Refactor of KEYREAD optimization switch so that KEYREAD
handler state is in sync with st_table::key_read flag.
All SQL code is supposed to switch KEYREAD optimization
via st_table::set_keyread().
sql/opt_sum.cc:
Refactor of KEYREAD optimization switch so that KEYREAD
handler state is in sync with st_table::key_read flag.
All SQL code is supposed to switch KEYREAD optimization
via st_table::set_keyread().
sql/sql_select.cc:
Refactor of KEYREAD optimization switch so that KEYREAD
handler state is in sync with st_table::key_read flag.
All SQL code is supposed to switch KEYREAD optimization
via st_table::set_keyread().
sql/sql_update.cc:
Refactor of KEYREAD optimization switch so that KEYREAD
handler state is in sync with st_table::key_read flag.
All SQL code is supposed to switch KEYREAD optimization
via st_table::set_keyread().
sql/table.cc:
Refactor of KEYREAD optimization switch so that KEYREAD
handler state is in sync with st_table::key_read flag.
All SQL code is supposed to switch KEYREAD optimization
via st_table::set_keyread().
sql/table.h:
Refactor of KEYREAD optimization switch so that KEYREAD
handler state is in sync with st_table::key_read flag.
All SQL code is supposed to switch KEYREAD optimization
via st_table::set_keyread().
Grouping by a subquery in a query with a distinct aggregate
function lead to a wrong result (wrong and unordered
grouping values).
There are two related problems:
1) The query like this:
SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c
FROM t1 GROUP BY aa
returned wrong result, because the outer reference "t1.a"
in the subquery was substituted with the Item_ref item.
The Item_ref item obtains data from the result_field object
that refreshes once after the end of each group. This data
is not applicable to filesort since filesort() doesn't care
about groups (and doesn't update result_field objects with
copy_fields() and so on). Also that data is not applicable
to group separation algorithm: end_send_group() checks every
record with test_if_group_changed() that evaluates Item_ref
items, but it refreshes those Item_ref-s only after the end
of group, that is a vicious circle and the grouped column
values in the output are shifted.
Fix: if
a) we grouping by a subquery and
b) that subquery has outer references to FROM list
of the grouping query,
then we substitute these outer references with
Item_direct_ref like references under aggregate
functions: Item_direct_ref obtains data directly
from the current record.
2) The query with a non-trivial grouping expression like:
SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c
FROM t1 GROUP BY aa+0
also returned wrong result, since JOIN::exec() substitutes
references to top-level aliases in SELECT list with Item_copy
caching items. Item_copy items have same refreshing policy
as Item_ref items, so the whole groping expression with
Item_copy inside returns wrong result in filesort() and
end_send_group().
Fix: include aliased items into GROUP BY item tree instead
of Item_ref references to them.
mysql-test/r/group_by.result:
Test case for bug #45640
mysql-test/t/group_by.test:
Test case for bug #45640
sql/item.cc:
Bug #45640: optimizer bug produces wrong results
Item_field::fix_fields() has been modified to resolve
aliases in GROUP BY item trees into aliased items instead
of Item_ref items.
sql/item.h:
Bug #45640: optimizer bug produces wrong results
- Item::find_item_processor() has been introduced.
- Item_ref::walk() has been modified to apply processors
to itself too (not only to referenced item).
sql/mysql_priv.h:
Bug #45640: optimizer bug produces wrong results
fix_inner_refs() has been modified to accept group_list
parameter.
sql/sql_lex.cc:
Bug #45640: optimizer bug produces wrong results
Initialization of st_select_lex::group_fix_field has
been added.
sql/sql_lex.h:
Bug #45640: optimizer bug produces wrong results
The st_select_lex::group_fix_field field has been introduced
to control alias resolution in Itef_fied::fix_fields.
sql/sql_select.cc:
Bug #45640: optimizer bug produces wrong results
- The fix_inner_refs function has been modified to treat
subquery outer references like outer fields under aggregate
functions, if they are included in GROUP BY item tree.
- The find_order_in_list function has been modified to
fix Item_field alias fields included in the GROUP BY item
trees in a special manner.
Fixed 2 problems :
1. test_if_order_by_key() was continuing on the primary key
as if it has a primary key suffix (as the secondary keys do).
This leads to crashes in ORDER BY <pk>,<pk>.
Fixed by not treating the primary key as the secondary one
and not depending on it being clustered with a primary key.
2. The cost calculation was trying to read the records
per key when operating on ORDER BYs that order on all of the
secondary key + some of the primary key.
This leads to crashes because of out-of-bounds array access.
Fixed by assuming we'll find 1 record per key in such cases.
subselect_single_select_engine::exec()
When a subquery doesn't need to be evaluated because
it returns only aggregate functions and these aggregates
can be calculated from the metadata about the table it
was not updating all the relevant members of the JOIN
structure to reflect that this is a constant query.
This caused problems to the enclosing subquery
('<> SOME' in the test case above) trying to read some
data about the tables.
Fixed by setting const_tables to the number of tables
when the SELECT is optimized away.
error in the query.
Fixes a leak after materializing a GROUP BY subquery to a
temp table when the subquery has a blob column in the SELECT
list.
Fixed by correctly destructing temporary buffers after doing
the conversion.
