with the test case added by this patch.
The bug cannot be reproduced with the same test case for the main
5.3 tree because the backported fix for bug 59696 masks the
problem that causes the crash in the mentioned test case. It's not
clear weather this fix masks this problem in all possible cases.
Anyway the patch for bug 698882 introduced some inconsistent data
structures that could contain indirect references to deleted object.
It happened when two Item_equal objects were merged and the Item_field
list of the second object was joined to such list of the first object.
This operation required adjustment of the backward pointers in
Item fields from the joined list. However the adjustment was missing
and this caused crashes in the tree for mwl#128.
Now the backward pointers are set only when Item_equal items are
completely built and are not changed anymore.
ZERO
When dates are represented internally as strings, i.e. when a string constant
is compared to a date value, both values are converted to long integers,
ostensibly for fast comparisons. DATE typed integer values are converted to
DATETIME by multiplying by 1,000,000 (each digit pair representing hour,
minute and second, respectively). But the mechanism did not distuinguish
cached INTEGER values, already in correct format, from newly converted
strings.
Fixed by marking the INTEGER cache as being of DATETIME format.
Made sure that the optimal fields are used by TABLE_REF objects
when building index access keys to joined tables.
Fixed a bug in the template function that sorts the elements of
a list using the bubble sort algorithm. The bug caused poor
performance of the function. Also added an optimization that
skips comparison with the most heavy elements that has been
already properly placed in the list.
Made the comparison of the fields belonging to the same Item_equal
more granular: fields belonging to the same table are also ordered
according to some rules.
get_year_value() contains code to convert 2-digits year to
4-digits. The fix for Bug#49910 added a check on the size of
the underlying field so that this conversion is not done for
YEAR(4) values. (Since otherwise one would convert invalid
YEAR(4) values to valid ones.)
The existing check does not work when Item_cache is used, since
it is not detected when the cache is based on a Field. The
reported change in behavior is due to Bug#58030 which added
extra cached items in min/max computations.
The elegant solution would be to implement
Item_cache::real_item() to return the underlying Item.
However, some side effects are observed (change in explain
output) that indicates that such a change is not straight-
forward, and definitely not appropriate for an MRU.
Instead, a Item_cache::field() method has been added in order
to get access to the underlying field. (This field() method
eliminates the need for Item_cache::eq_def() used in
test_if_ref(), but in order to limit the scope of this fix,
that code has been left as is.)
mysql-test/r/type_year.result:
Added test case for Bug#59211.
mysql-test/t/type_year.test:
Added test case for Bug#59211.
sql/item.h:
Added function Item_cache::field() to get access to the
underlying Field of a cached field Value.
sql/item_cmpfunc.cc:
Also check underlying fields of Item_cache, not just Item_Field,
when checking whether the value is of type YEAR(4) or not.
Fix: copy my_decimal by value, to avoid dangling pointers.
mysql-test/r/func_math.result:
New test case.
mysql-test/t/func_math.test:
New test case.
sql/item_cmpfunc.cc:
No need to call fix_buffer_pointer() anymore.
sql/item_func.cc:
Copy my_decimal by value, to avoid dangling pointers.
sql/my_decimal.h:
Implement proper copy constructor and assignment operator for my_decimal.
sql/sql_analyse.cc:
No need to call fix_buffer_pointer() anymore.
strings/decimal.c:
Remove #line directive: it messes up TAGS and it confuses gdb when debugging.
Item_equal::val_int() checked for NULL-values by checking Item::null_value
*before* the respective ::store_value() and ::cmp(Item*) metods where called.
As Item::null_value is set by these metods, the value of 'null_value'
is not valid until *after* ::store_value() or ::cmp() has
been called for the Item object.
Fix is to swap order of ::store_value()/::cmp() and checking of Item::null_value.
This pattern is widely used other places inside item_cmpfunc.cc .
- Removed files specific to compiling on OS/2
- Removed files specific to SCO Unix packaging
- Removed "libmysqld/copyright", text is included in documentation
- Removed LaTeX headers for NDB Doxygen documentation
- Removed obsolete NDB files
- Removed "mkisofs" binaries
- Removed the "cvs2cl.pl" script
- Changed a few GPL texts to use "program" instead of "library"
--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 compiler warning
mysql-test/r/named_pipe.result:
Fixed test results for windows builds
mysql-test/r/shm.result:
Fixed test results for windows builds
sql/item_cmpfunc.cc:
Fixed compiler warning about uninitialized "first"
- 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.
ESCAPE argument might be empty string. It leads
to server crash under some circumstances.
The fix:
-added check if ESCAPE argument result is not empty string
mysql-test/r/ctype_latin1.result:
test case
mysql-test/t/ctype_latin1.test:
test case
sql/item_cmpfunc.cc:
-added check if ESCAPE argument result is not empty string
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.
Problem: CASE didn't work with a mixture of different character
sets in THEN/ELSE in some cases.
This happened because after character set aggregation
newly created Item_func_conv_charset items corresponding
to THEN/ELSE arguments were not put back to args[] array.
Fix:
put all Item_func_conv_charset back to args[].
@ mysql-test/include/ctype_numconv.inc
@ mysql-test/r/ctype_ucs.result
Adding tests
@ sql/item_cmpfunc.cc
Put "agg" back to args[] after character set aggregation.
sql/field.cc:
Remove feature of 'new_mode' that was never implemtented in a newer MySQL version.
sql/item_cmpfunc.cc:
Boyer more is stable; Don't have to be protected by --skip-new anymore
sql/mysqld.cc:
Don't disable some proven stable functions with --skip-new
sql/records.cc:
Don't disable record caching with --safe-mode anymore
sql/sql_delete.cc:
Do fast truncate even if --skip-new or --safe is used
sql/sql_parse.cc:
Use always mysql_optimizer() for optimizer (instead of mysql_recreate_table() in case of --safe or --skip-new)
sql/sql_select.cc:
Don't disable 'only_eq_ref_tables' if --safe is used.
sql/sql_yacc.yy:
Removed not meaningfull test of --old
- Corrected a wrong result that was recorded by the MySQL fix for BUG#39069.
- Removed Item_func_isnull::cached_value and all the logic around this custom-made
caching of the NULL result because MWL#89 optimizes subqueries before the outer
query is being executed, and this cache cannot be made easily to work for all
kinds of Items (specifically Item_sum_sum, but others too).
The problem could be demonstrated with an outer join of two single-row
tables where the values of the join attributes were null. Any query
with such a join could return a wrong result set if the where
condition of the query was not empty. For queries with empty
where conditions the result sets were correct.
This was the consequence of two bugs in the code:
- Item_equal objects for on conditions of outer joins were
not built if the processed query had no where condition
- the check for null values in the code that evaluated constant
Item_equal objects was incorrect.
Fixed both above problems.
Added a test case for the bug and adjusted results for some other
test cases.
to 5.5 (removed one test case as it is no longer valid).
mysql-test/r/select.result:
Removed a part of the test case for bug#48291 since it is not
valid anymore. The comments for the removed part were actually
describing a side-effect from the problem addressed by the
addendum patch for bug #54190.
mysql-test/t/select.test:
Removed a part of the test case for bug#48291 since it is not
valid anymore. The comments for the removed part were actually
describing a side-effect from the problem addressed by the
addendum patch for bug #54190.
result
Row subqueries producing no rows were not handled as UNKNOWN
values in row comparison expressions.
That was a result of the following two problems:
1. Item_singlerow_subselect did not mark the resulting row
value as NULL/UNKNOWN when no rows were produced.
2. Arg_comparator::compare_row() did not take into account that
a whole argument may be NULL rather than just individual scalar
values.
Before bug#34384 was fixed, the above problems were hidden
because an uninitialized (i.e. without any stored value) cached
object would appear as NULL for scalar values in a row subquery
returning an empty result. After the fix
Arg_comparator::compare_row() would try to evaluate
uninitialized cached objects.
Fixed by removing the aforementioned problems.
mysql-test/r/row.result:
Added a test case for bug #54190.
mysql-test/r/subselect.result:
Updated the result for a test relying on wrong behavior.
mysql-test/t/row.test:
Added a test case for bug #54190.
sql/item_cmpfunc.cc:
If either of the argument rows is NULL, return NULL as the
result of comparison.
sql/item_subselect.cc:
Adjust null_value for Item_singlerow_subselect depending on
whether a row has been produced by the row subquery.
The EXISTS transformation has additional switches to catch the known corner
cases that appear when transforming an IN predicate into EXISTS. Guarded
conditions are used which are deactivated when a NULL value is seen in the
outer expression's row. When the inner query block supplies NULL values,
however, they are filtered out because no distinction is made between the
guarded conditions; guarded NOT x IS NULL conditions in the HAVING clause that
filter out NULL values cannot be de-activated in isolation from those that
match values or from the outer expression or NULL's.
The above problem is handled by making the guarded conditions remember whether
they have rejected a NULL value or not, and index access methods are taking
this into account as well.
The bug consisted of
1) Not resetting the property for every nested loop iteration on the inner
query's result.
2) Not propagating the NULL result properly from inner query to IN optimizer.
3) A hack that may or may not have been needed at some point. According to a
comment it was aimed to fix#2 by returning NULL when FALSE was actually
the result. This caused failures when #2 was properly fixed. The hack is
now removed.
The fix resolves all three points.
Fixed a crash in Item_equal::fix_length_and_dec that was a result of the
architecture of the MWL#89 subquery optimization.
The injection of IN->EXISTS predicates for subqueries happened inside
make_join_statistics, after constant substitution, but before multiple
equality substitution done by substitute_for_best_equal_field. As a
result, when we called fix_fields for the WHERE clause after the injection
of IN->EXISTS predicates, Item_equal was not fixed, and it was in a state
not anticipated by Item_equal::fix_length_and_dec - the Item_equal
containted only a constant, and no fields at all.
The fix takes into account this new possible state when calling fix_fields.
