mysql-test/r/subselect4.result:
Moved test case for LP BUG#718593 into the correct test file subselect_mat_cost_bugs.test.
mysql-test/t/subselect4.test:
Moved test case for LP BUG#718593 into the correct test file subselect_mat_cost_bugs.test.
client/mysqltest.cc:
Column names.
mysql-test/r/grant_cache_no_prot.result:
fix of text.
mysql-test/r/grant_cache_ps_prot.result:
Fix of test.
mysql-test/r/query_cache.result:
Switching on and off query cache.
mysql-test/t/query_cache.test:
Switching on and off query cache.
mysys/charset.c:
Fix of parser.
sql/handler.cc:
thd added to parameters.
sql/log_event.cc:
thd added to parameters.
sql/log_event_old.cc:
thd added to parameters.
sql/mysql_priv.h:
Fixed functions definitions.
sql/mysqld.cc:
Comments stripping.
sql/set_var.cc:
Switching on and off query cache.
sql/set_var.h:
Switching on and off query cache.
sql/share/errmsg.txt:
New errors.
sql/sql_cache.cc:
Switching query cache on and off, removing comments.
sql/sql_cache.h:
thd added to parameters.
sql/sql_class.h:
Comments stripping.
sql/sql_db.cc:
thd added to parameters.
sql/sql_lex.cc:
lex fixed.
sql/sql_parse.cc:
thd added to parameters.
Analysis:
The method st_select_lex::optimize_unflattened_subqueries()
incorrectly propagated to each subquery the complete
select_options flag set for the whole query. Among other
flags in select_options, this propagated incorrectly the
STRAIGHT_JOIN flag from the upper query to the subquery.
Solution:
During EXPLAIN set only the SELECT_DESCRIBE bit in the
select_options of the subquery.
mysql-test/r/explain.result:
fixed results (new item)
mysql-test/r/subselect.result:
fixed results (new item)
mysql-test/r/subselect_no_mat.result:
fixed results (new item)
mysql-test/r/subselect_no_opts.result:
fixed results (new item)
mysql-test/r/subselect_no_semijoin.result:
Fixed results (new item)
mysql-test/suite/pbxt/r/subselect.result:
Fixed results (new item)
mysql-test/t/explain.test:
Fixed results (correct behaviour)
sql/item_cmpfunc.cc:
Pass through for max/min
sql/item_subselect.cc:
moving max/min
sql/item_subselect.h:
moving max/min
sql/mysql_priv.h:
new uncacheble flags added
sql/opt_subselect.cc:
maxmin moved.
sql/opt_subselect.h:
New function for maxmin.
sql/sql_class.h:
debug code
sql/sql_lex.cc:
Fixed flags.
Limit setting fixed.
sql/sql_lex.h:
2 new flags.
sql/sql_select.cc:
Prepare divided on 2 function to be able recollect some info after transformation.
sql/sql_select.h:
Prepare divided on 2 functions.
- Auto-merge with 5.3 main.
- Changed the test for LP BUG#719198 so that
an two more queries were added, and removed a
query that produces a wrong result due to an
unrelated problem. The wrong result is submitted
as a separate bug.
Fixed memory leak from HEAP tables that was not deleted properly
BUILD/compile-alpha-ccc:
Use g++ instead of gcc for linking
BUILD/compile-alpha-debug:
Use g++ instead of gcc for linking
BUILD/compile-pentium-pgcc:
Use g++ instead of gcc for linking
BUILD/compile-solaris-sparc:
Use g++ instead of gcc for linking
BUILD/compile-solaris-sparc-debug:
Use g++ instead of gcc for linking
BUILD/compile-solaris-sparc-purify:
Use g++ instead of gcc for linking
sql/item.cc:
Safety fixes for expr_cache
Call Item_result:field::cleanup() in Item_cache_wrapper::cleanup()
More DBUG_PRINT
sql/sql_base.cc:
Simple optimization for setup_wild
More DBUG_PRINT
sql/sql_expression_cache.cc:
Added header
Removed not needed initialization
sql/sql_lex.cc:
More DBUG_PRINT
sql/sql_select.cc:
More DBUG_PRINT
Fixed memory leak from HEAP tables that was not deleted properly
storage/heap/hp_create.c:
More DBUG_PRINT
- Fixed some issues with partitions and connection_string, which also fixed lp:716890 "Pre- and post-recovery crash in Aria"
- Fixed wrong assert in Aria
Now need to merge with latest xtradb before pushing
sql/ha_partition.cc:
Ensure that m_ordered_rec_buffer is not freed before close.
sql/mysqld.cc:
Changed to use opt_stack_trace instead of opt_pstack.
Removed references to pstack
sql/partition_element.h:
Ensure that connect_string is initialized
storage/maria/ma_key_recover.c:
Fixed wrong assert
Fixed a memory leak found by valgrind. The memory leak was
a result of JOINs corresponding to subselects in a global
ORDER BY of a UNION not being cleaned up because the
fake_select of the UNION didn't point down to the subquery
select.
--Bug#52157 various crashes and assertions with multi-table update, stored function
--Bug#54475 improper error handling causes cascading crashing failures in innodb/ndb
--Bug#57703 create view cause Assertion failed: 0, file .\item_subselect.cc, line 846
--Bug#57352 valgrind warnings when creating view
--Recently discovered problem when a nested materialized derived table is used
before being populated and it leads to incorrect result
We have several modes when we should disable subquery evaluation.
The reasons for disabling are different. It could be
uselessness of the evaluation as in case of 'CREATE VIEW'
or 'PREPARE stmt', or we should disable subquery evaluation
if tables are not locked yet as it happens in bug#54475, or
too early evaluation of subqueries can lead to wrong result
as it happened in Bug#19077.
Main problem is that if subquery items are treated as const
they are evaluated in ::fix_fields(), ::fix_length_and_dec()
of the parental items as a lot of these methods have
Item::val_...() calls inside.
We have to make subqueries non-const to prevent unnecessary
subquery evaluation. At the moment we have different methods
for this. Here is a list of these modes:
1. PREPARE stmt;
We use UNCACHEABLE_PREPARE flag.
It is set during parsing in sql_parse.cc, mysql_new_select() for
each SELECT_LEX object and cleared at the end of PREPARE in
sql_prepare.cc, init_stmt_after_parse(). If this flag is set
subquery becomes non-const and evaluation does not happen.
2. CREATE|ALTER VIEW, SHOW CREATE VIEW, I_S tables which
process FRM files
We use LEX::view_prepare_mode field. We set it before
view preparation and check this flag in
::fix_fields(), ::fix_length_and_dec().
Some bugs are fixed using this approach,
some are not(Bug#57352, Bug#57703). The problem here is
that we have a lot of ::fix_fields(), ::fix_length_and_dec()
where we use Item::val_...() calls for const items.
3. Derived tables with subquery = wrong result(Bug19077)
The reason of this bug is too early subquery evaluation.
It was fixed by adding Item::with_subselect field
The check of this field in appropriate places prevents
const item evaluation if the item have subquery.
The fix for Bug19077 fixes only the problem with
convert_constant_item() function and does not cover
other places(::fix_fields(), ::fix_length_and_dec() again)
where subqueries could be evaluated.
Example:
CREATE TABLE t1 (i INT, j BIGINT);
INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
SELECT * FROM (SELECT MIN(i) FROM t1
WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3;
DROP TABLE t1;
4. Derived tables with subquery where subquery
is evaluated before table locking(Bug#54475, Bug#52157)
Suggested solution is following:
-Introduce new field LEX::context_analysis_only with the following
possible flags:
#define CONTEXT_ANALYSIS_ONLY_PREPARE 1
#define CONTEXT_ANALYSIS_ONLY_VIEW 2
#define CONTEXT_ANALYSIS_ONLY_DERIVED 4
-Set/clean these flags when we perform
context analysis operation
-Item_subselect::const_item() returns
result depending on LEX::context_analysis_only.
If context_analysis_only is set then we return
FALSE that means that subquery is non-const.
As all subquery types are wrapped by Item_subselect
it allow as to make subquery non-const when
it's necessary.
mysql-test/r/derived.result:
test case
mysql-test/r/multi_update.result:
test case
mysql-test/r/view.result:
test case
mysql-test/suite/innodb/r/innodb_multi_update.result:
test case
mysql-test/suite/innodb/t/innodb_multi_update.test:
test case
mysql-test/suite/innodb_plugin/r/innodb_multi_update.result:
test case
mysql-test/suite/innodb_plugin/t/innodb_multi_update.test:
test case
mysql-test/t/derived.test:
test case
mysql-test/t/multi_update.test:
test case
mysql-test/t/view.test:
test case
sql/item.cc:
--removed unnecessary code
sql/item_cmpfunc.cc:
--removed unnecessary checks
--THD::is_context_analysis_only() is replaced with LEX::is_ps_or_view_context_analysis()
sql/item_func.cc:
--refactored context analysis checks
sql/item_row.cc:
--removed unnecessary checks
sql/item_subselect.cc:
--removed unnecessary code
--added DBUG_ASSERT into Item_subselect::exec()
which asserts that subquery execution can not happen
if LEX::context_analysis_only is set, i.e. at context
analysis stage.
--Item_subselect::const_item()
Return FALSE if LEX::context_analysis_only is set.
It prevents subquery evaluation in ::fix_fields &
::fix_length_and_dec at context analysis stage.
sql/item_subselect.h:
--removed unnecessary code
sql/mysql_priv.h:
--Added new set of flags.
sql/sql_class.h:
--removed unnecessary code
sql/sql_derived.cc:
--added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_lex.cc:
--init LEX::context_analysis_only field
sql/sql_lex.h:
--New LEX::context_analysis_only field
sql/sql_parse.cc:
--removed unnecessary code
sql/sql_prepare.cc:
--removed unnecessary code
--added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_select.cc:
--refactored context analysis checks
sql/sql_show.cc:
--added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_view.cc:
--added LEX::context_analysis_only analysis intialization/cleanup
- Fixed problem with oqgraph and 'make dist'
Note that after this merge we have a problem show in join_outer where we examine too many rows in one specific case (related to BUG#57024).
This will be fixed when mwl#128 is merged into 5.3.
Registration of pointer change if we assign it to other pointer which should be identical after statement execution (PS/SP).
mysql-test/r/subselect.result:
Test suite.
mysql-test/t/subselect.test:
Test suite.
sql/sql_class.cc:
The procedure of the pointer registration.
sql/sql_class.h:
The procedure of the pointer registration.
sql/sql_lex.cc:
Registration of pointer change if we assign it to other pointer which should be identical after statement execution (PS/SP).
Merge 5.3-mwl89 into 5.3 main.
There is one remaining test failure in this merge:
innodb_mysql_lock2. All other tests have been checked to
deliver the same results/explains as 5.3-mwl89, including
the few remaining wrong results.
Improved handling of EXPLAIN statements for subqueries.
This patch specifically solves the problem when EXPLAIN reports:
"const row not found"
instead of
"no matching row in const table".
Phase 3: Implementation of re-optimization of subqueries with injected predicates
and cost comparison between Materialization and IN->EXISTS strategies.
The commit contains the following known problems:
- The implementation of EXPLAIN has not been re-engineered to reflect the
changes in subquery optimization. EXPLAIN for subqueries is called during
the execute phase, which results in different code paths during JOIN::optimize
and thus in differing EXPLAIN messages for constant/system tables.
- There are some valgrind warnings that need investigation
- Several EXPLAINs with minor differences need to be reconsidered after fixing
the EXPLAIN problem above.
This patch also adds one extra optimizer_switch: 'in_to_exists' for complete
manual control of the subquery execution strategies.
- Changed to still use bcmp() in certain cases becasue
- Faster for short unaligneed strings than memcmp()
- Bettern when using valgrind
- Changed to use my_sprintf() instead of sprintf() to get higher portability for old systems
- Changed code to use MariaDB version of select->skip_record()
- Removed -%::SCCS/s.% from Makefile.am:s to remove automake warnings
Fix compiler warnings.
mysys/stacktrace.c:
Tag unused parameters.
sql/sql_lex.cc:
Variable becomes unused in non-debug builds. Also, no need to
assert the obvious.
/*![:version:] Query Code */, where [:version:] is a sequence of 5
digits representing the mysql server version(e.g /*!50200 ... */),
is a special comment that the query in it can be executed on those
servers whose versions are larger than the version appearing in the
comment. It leads to a security issue when slave's version is larger
than master's. A malicious user can improve his privileges on slaves.
Because slave SQL thread is running with SUPER privileges, so it can
execute queries that he/she does not have privileges on master.
This bug is fixed with the logic below:
- To replace '!' with ' ' in the magic comments which are not applied on
master. So they become common comments and will not be applied on slave.
- Example:
'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /*!99999 ,(3)*/
will be binlogged as
'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /* 99999 ,(3)*/
mysql-test/suite/rpl/t/rpl_conditional_comments.test:
Test the patch for this bug.
sql/mysql_priv.h:
Rename inBuf as rawBuf and remove the const limitation.
sql/sql_lex.cc:
To replace '!' with ' ' in the magic comments which are not applied on
master.
sql/sql_lex.h:
Remove the const limitation on parameter buff, as it can be modified in the function since
this patch.
Add member function yyUnput for Lex_input_stream. It set a character back the query buff.
sql/sql_parse.cc:
Rename inBuf as rawBuf and remove the const limitation.
sql/sql_partition.cc:
Remove the const limitation on parameter part_buff, as it can be modified in the function since
this patch.
sql/sql_partition.h:
Remove the const limitation on parameter part_buff, as it can be modified in the function since
this patch.
sql/table.h:
Remove the const limitation on variable partition_info, as it can be modified since
this patch.
There were two problems that caused wrong results reported with this bug.
1. In some cases stored(persistent) virtual columns were not marked
in the write_set and in the vcol_set bitmaps.
2. If the list of fields in an insert command was empty then the values of
the stored virtual columns were set to default.
To fix the first problem the function st_table::mark_virtual_columns_for_write
was modified. Now the function has a parameter that says whether the virtual
columns are to be marked for insert or for update.
To fix the second problem a special handling of empty insert lists is
added in the function fill_record().
libmysqld/Makefile.am:
The new file added.
mysql-test/r/index_merge_myisam.result:
subquery_cache optimization option added.
mysql-test/r/myisam_mrr.result:
subquery_cache optimization option added.
mysql-test/r/subquery_cache.result:
The subquery cache tests added.
mysql-test/r/subselect3.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect3_jcl6.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect_no_mat.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_opts.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_semijoin.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj_jcl6.result:
subquery_cache optimization option added.
mysql-test/t/subquery_cache.test:
The subquery cache tests added.
mysql-test/t/subselect3.test:
Subquery cache switched off to avoid changing read statistics.
sql/CMakeLists.txt:
The new file added.
sql/Makefile.am:
The new files added.
sql/item.cc:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item.h:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item_cmpfunc.cc:
Subquery cache added.
sql/item_cmpfunc.h:
Subquery cache added.
sql/item_subselect.cc:
Subquery cache added.
sql/item_subselect.h:
Subquery cache added.
sql/item_sum.cc:
Registration of subquery parameters added.
sql/mysql_priv.h:
subquery_cache optimization option added.
sql/mysqld.cc:
subquery_cache optimization option added.
sql/opt_range.cc:
Fix due to subquery cache.
sql/opt_subselect.cc:
Parameters of the function cahnged.
sql/procedure.h:
.h file guard added.
sql/sql_base.cc:
Registration of subquery parameters added.
sql/sql_class.cc:
Option to allow add indeces to temporary table.
sql/sql_class.h:
Item iterators added.
Option to allow add indeces to temporary table.
sql/sql_expression_cache.cc:
Expression cache for caching subqueries added.
sql/sql_expression_cache.h:
Expression cache for caching subqueries added.
sql/sql_lex.cc:
Registration of subquery parameters added.
sql/sql_lex.h:
Registration of subqueries and subquery parameters added.
sql/sql_select.cc:
Subquery cache added.
sql/sql_select.h:
Subquery cache added.
sql/sql_union.cc:
A new parameter to the function added.
sql/sql_update.cc:
A new parameter to the function added.
sql/table.cc:
Procedures to manage temporarty tables index added.
sql/table.h:
Procedures to manage temporarty tables index added.
storage/maria/ha_maria.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
storage/maria/ha_maria.h:
.h file guard added.
storage/myisam/ha_myisam.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
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.
Fixed some bugs introduced in 5.1.47
Disabled some tests until we have merged with latest Xtradb
configure.in:
Added testing if valgrind/memcheck.h exists
storage/pbxt/src/ha_pbxt.cc:
LOCK_plugin is not anymore locked in init
Item_hex_string::Item_hex_string
The status of memory allocation in the Lex_input_stream (called
from the Parser_state constructor) was not checked which led to
a parser crash in case of the out-of-memory error.
The solution is to introduce new init() member function in
Parser_state and Lex_input_stream so that status of memory
allocation can be returned to the caller.
mysql-test/r/error_simulation.result:
Added a test case for bug #42064.
mysql-test/t/error_simulation.test:
Added a test case for bug #42064.
mysys/my_alloc.c:
Added error injection code for the regression test.
mysys/my_malloc.c:
Added error injection code for the regression test.
mysys/safemalloc.c:
Added error injection code for the regression test.
sql/event_data_objects.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/mysqld.cc:
Added error injection code for the regression test.
sql/sp.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_lex.cc:
Moved memory allocation from constructor to the separate init()
member function.
Added error injection code for the regression test.
sql/sql_lex.h:
Moved memory allocation from constructor to the separate init()
member function.
sql/sql_parse.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_partition.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_prepare.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_trigger.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_view.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures..
sql/thr_malloc.cc:
Added error injection code for the regression test.
The problem was that a syntactically invalid trigger could cause
the server to crash when trying to list triggers. The crash would
happen due to a mishap in the backup/restore procedure that should
protect parser items which are not associated with the trigger. The
backup/restore is used to isolate the parse tree (and context) of
a statement from the load (and parsing) of a trigger. In this case,
a error during the parsing of a trigger could cause the improper
backup/restore sequence.
The solution is to properly restore the original statement context
before the parser is exited due to syntax errors in the trigger body.
mysql-test/r/trigger.result:
Add test case result for Bug#50755
mysql-test/t/trigger.test:
Add test case for Bug#50755
sql/sp_head.cc:
Merge sp_head::destroy() and sp_head destructor. Retrieve THD
from the LEX so that m_thd is not necessary.
sql/sql_lex.cc:
Explicitly restore the original environment.
Add some extra error output and code cleanup in an attempt to fix/debug
a rare random testsuite problem in check_warnings, where the exit code
from mysqltest is somehow corrupted inside mysql-test-run.pl.
include/my_global.h:
Fix compiler warnings on some platforms.
mysql-test/lib/My/SafeProcess.pm:
Move dereference of $? subprocess exit code closer to where it is generated,
to make the code more robust and on the chance that this will fix the
occasional problems in check_warnings we see in Buildbot.
mysql-test/mysql-test-run.pl:
When check_warnings failed, also log the mysqld server for which it failed.
sql/sql_lex.cc:
Fix compiler warning about possibly uninitialised value, by rewriting a for()
loop that is always executed at least once into a do .. while() loop with an
assert.
sql/table.cc:
Fix compiler warning about uninitialised value.
storage/federatedx/ha_federatedx.cc:
Fix uninitialised variable.
storage/maria/ma_delete.c:
Fix compiler warning about uninitialised value.
storage/maria/ma_loghandler.c:
Fix compiler warning about uninitialised value.
storage/myisam/ft_stopwords.c:
Fix compiler warning.
storage/myisam/mi_write.c:
Fix compiler warning about possibly uninitialised value, by rewriting a while()
loop that is always executed at least once into a do .. while() loop with an
assert.
storage/xtradb/btr/btr0cur.c:
Fix compiler warning about possibly uninitialised value.
support-files/compiler_warnings.supp:
Fix warning suppression to cover all cases in yassl.
vio/viossl.c:
Fix compiler warning.
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.
