Bug#11766642: crash in Item_field::register_field_in_read_map
with view
(Former 59793)
Prior to the refactoring in this patch, Item_cond_xor behaved
partially as an Item_cond and partially as an Item_func. The
reasoning behind this was that XOR is currently not optimized
(thus should be Item_func instead of Item_cond), but it was
planned optimize it in the future (thus, made Item_cond anyway
to ease optimization later).
Even though Item_cond inherits from Item_func, there are
differences between these two. One difference is that the
arguments are stored differently. Item_cond stores them in a
list while Item_func store them in an args[].
BUG no 45221 was caused by Item_cond_xor storing arguments in
the list while users of the objects would look for them in
args[]. The fix back then was to store the arguments in both
locations.
In this bug, Item_cond_xor initially gets two Item_field
arguments. These are stored in the list inherited from
Item_cond and in args[] inherited from Item_func. During
resolution, find_field_in_view() replaces the Item_fields
stored in the list with Item_direct_view_refs, but args[]
still points to the unresolved Item_fields. This shows that
the fix for 45221 was incorrect.
The refactoring performed in this patch removes the confusion
by making the XOR item an Item_func period. A neg_transformer()
is also implemented for Item_func_xor to improve performance
when negating XOR expressions. An XOR is negated by negating
one of the operands.
Analysis:
This bug is yet another incarnation of the generic problem
where optimization of the outer query triggers evaluation
of a subquery, and this evaluation performs a destructive
change to the subquery plan. Specifically a temp table is
created for the DISTINCT operation that replaces the
original subquery table. Later, select_describe() attempts
to print the table name, however, there is no corresponding
TABLE_LIST object to the internal temp table, so we get a
crash. Execution works fine because it is not interested in
the corresponding TABLE_LIST object (or its name).
Solution:
Similar to other such bugs, block the evaluation of expensive
Items in convert_const_to_int().
microsecond(TIME)
alter table datetime<->datetime(6)
max(TIME), mix(TIME)
mysql-test/t/func_if.test:
fix the test case of avoid overflow
sql/field.cc:
don't use make_date() and make_time()
sql/field.h:
correct eq_def() for temporal fields
sql/item.cc:
move datetime caching from Item_cache_int
to Item_cache_temporal
sql/item.h:
move datetime caching from Item_cache_int
to Item_cache_temporal
sql/item_func.cc:
use existing helper methods, don't duplicate
sql/item_sum.cc:
argument cache must use argument's cmp_type, not result_type.
sql/item_timefunc.cc:
use existing methods, don't tuplicate.
remove unused function.
fix micorseconds() to support TIME argument
sql/mysql_priv.h:
dead code
sql/time.cc:
dead code
compilation error in mysys/my_getsystime.c fixed
some redundant code removed
sec_to_time, time_to_sec, from_unixtime, unix_timestamp, @@timestamp now
use decimal, not double for numbers with a fractional part.
purge_master_logs_before_date() fixed
many bugs in corner cases fixed
mysys/my_getsystime.c:
compilation failure fixed
sql/sql_parse.cc:
don't cut corners. it backfires.
A lot of small fixes and new test cases.
client/mysqlbinlog.cc:
Cast removed
client/mysqltest.cc:
Added missing DBUG_RETURN
include/my_pthread.h:
set_timespec_time_nsec() now only takes one argument
mysql-test/t/date_formats.test:
Remove --disable_ps_protocl as now also ps supports microseconds
mysys/my_uuid.c:
Changed to use my_interval_timer() instead of my_getsystime()
mysys/waiting_threads.c:
Changed to use my_hrtime()
sql/field.h:
Added bool special_const_compare() for fields that may convert values before compare (like year)
sql/field_conv.cc:
Added test to get optimal copying of identical temporal values.
sql/item.cc:
Return that item_int is equal if it's positive, even if unsigned flag is different.
Fixed Item_cache_str::save_in_field() to have identical null check as other similar functions
Added proper NULL check to Item_cache_int::save_in_field()
sql/item_cmpfunc.cc:
Don't call convert_constant_item() if there is nothing that is worth converting.
Simplified test when years should be converted
sql/item_sum.cc:
Mark cache values in Item_sum_hybrid as not constants to ensure they are not replaced by other cache values in compare_datetime()
sql/item_timefunc.cc:
Changed sec_to_time() to take a my_decimal argument to ensure we don't loose any sub seconds.
Added Item_temporal_func::get_time() (This simplifies some things)
sql/mysql_priv.h:
Added Lazy_string_decimal()
sql/mysqld.cc:
Added my_decimal constants max_seconds_for_time_type, time_second_part_factor
sql/table.cc:
Changed expr_arena to be of type CONVENTIONAL_EXECUTION to ensure that we don't loose any items that are created by fix_fields()
sql/tztime.cc:
TIME_to_gmt_sec() now sets *in_dst_time_gap in case of errors
This is needed to be able to detect if timestamp is 0
storage/maria/lockman.c:
Changed from my_getsystime() to set_timespec_time_nsec()
storage/maria/ma_loghandler.c:
Changed from my_getsystime() to my_hrtime()
storage/maria/ma_recovery.c:
Changed from my_getsystime() to mmicrosecond_interval_timer()
storage/maria/unittest/trnman-t.c:
Changed from my_getsystime() to mmicrosecond_interval_timer()
storage/xtradb/handler/ha_innodb.cc:
Added support for new time,datetime and timestamp
unittest/mysys/thr_template.c:
my_getsystime() -> my_interval_timer()
unittest/mysys/waiting_threads-t.c:
my_getsystime() -> my_interval_timer()
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.
sql/event_parse_data.cc:
don't use "not_used" variable
sql/item_timefunc.cc:
Item_temporal_func::fix_length_and_dec()
and other changes
sql/item_timefunc.h:
introducing Item_timefunc::fix_length_and_dec()
sql/share/errmsg.txt:
don't say "column X" in the error message that used not only for columns
include/my_time.h:
remove duplicate defines.
cast to ulonglong to avoid overflow
sql/field.cc:
perform sign extension when reading packed TIME values
sql/item_cmpfunc.cc:
when converting a string to a date for the purpose of comparing it with another date,
we should ignore strict sql mode.
sql/item_timefunc.cc:
better error message
sql/item_timefunc.h:
limit decimals appropriately
sql/share/errmsg.txt:
don't refer to an object as a "column" in error messages that are used not only for columns.
When a view is merged into a select all the depended_from fields
pointing to the select of the view should have been corrected to
point to the select where the view is used. It was not done yet.
This could lead to wrong results returned by queries such as
one from the test case for bug 33389.
Correction of outer references required walking through all items
of the proccesed qurery. To avoid this the following solution was
implemented.
Each select now contains a pointer to the select it is merged into
(if there is any). Such pointers allow to get the corrected value
of depended_from on the fly. The function Item_ident::get_depended_from
was introduced for this purpose.
Resolved all conflicts, bad merges and fixed a few minor bugs in the code.
Commented out the queries from multi_update, view, subselect_sj, func_str,
derived_view, view_grant that failed either with crashes in ps-protocol or
with wrong results.
The failures are clear indications of some bugs in the code and these bugs
are to be fixed.
Analysis:
The subquery is evaluated first during ref-optimization of the outer
query because the subquery is considered constant from the perspective
of the outer query. Thus an attempt is made to evaluate the MAX subquery
and use the new constant to drive an index nested loops join.
During this evaluation the inner-most subquery replaces the JOIN_TAB
with a new one that fetches the data from a temp table.
The function select_describe crashes at the lines:
TABLE_LIST *real_table= table->pos_in_table_list;
item_list.push_back(new Item_string(real_table->alias,
strlen(real_table->alias),
cs));
because 'table' is a temp table, and it has no corresponding table
reference. This 'real_table' is NULL, and real_table->alias results
in a crash.
Solution:
In the spirit of MWL#89 prevent the evaluation of expensive predicates
during optimization. This patch prevents the evaluation of expensive
predicates during ref optimization.
sql/item_subselect.h:
Remove unused class member. Not needed for the fix, but noticed now and removed.
Analysis:
During optimization of the subquery, in the call chain:
update_ref_and_keys -> add_key_fields ->
merge_key_fields -> Item_direct_ref::is_null -> Item_cache::is_null
The call to Item_cache::is_null() returns TRUE, which is wrong.
This results in Item_null replacing the field 'f3' in the KEY_FIELD,
then this Item_null is used for index access, producing a wrong result.
The reason why Item_cache::is_null returns wrong result is that
this Item_cache object is a cache of the left operand of IN, and was
updated in Item_in_optimizer::val_int. In MWL#89 the latter method is
called during the execution phase, which is after we optimize the subquery.
Therefore during the optization phase the left operand cache of IN was
not updated.
Solution:
Update the left operand cache during optimization if it is a constant.
This bug fix also discoveres and fixes a wrong IF statement in
convert_constant_item().
- COLUMN_CREATE(column_nr, value, [column_nr,value]...)
- COLUMN_ADD(blob,column_nr, value, column_nr,value]...)
- COLUMN_DELETE(blob, column_nr, column_nr...)
- COLUMN_EXISTS(blob, column_nr)
- COLUMN_LIST(blob, column_nr)
- COLUMN_GET(string, column_nr AS type)
Added cast(X as DOUBLE) and cast(x as INT)
Better warning and error messages for wrong cast's
Created some sub functions to simplify and reuse code.
Added a lot of conversation functions with error/warnings for what went wrong.
Fixed some issues when casting time to datetime.
Added functions to dynamic strings and Strings to allow one to move a string buffer from dynamic strings to String (to save malloc+ copy)
Added dynamic columns library to libmysqlclient
include/Makefile.am:
Added ma_dyncol.h
include/decimal.h:
Added 'const' to arguments for some functions.
include/my_sys.h:
Added dynstr_reassociate()
include/my_time.h:
Added TIME_SUBSECOND_RANGE
Added double_to_datetime()
Added flag argument to str_to_time()
libmysql/CMakeLists.txt:
Added mysys/ma_dyncol.c
libmysql/Makefile.shared:
Added ma_dyncol
libmysql/libmysql.c:
Added argument to str_to_time()
mysql-test/r/bigint.result:
Better error messages
mysql-test/r/cast.result:
Better warning and error messages
A lot of new cast() tests
mysql-test/r/func_math.result:
Better warning messages
mysql-test/r/func_str.result:
Better warning messages
mysql-test/r/func_time.result:
Better warning messages
mysql-test/r/sp-vars.result:
Better warning messages
mysql-test/r/strict.result:
Better warning messages
New test result
mysql-test/r/type_newdecimal.result:
Better warning messages
mysql-test/r/warnings.result:
Better warning messages
mysql-test/suite/funcs_1/r/innodb_func_view.result:
Updated results after better cast warnings
mysql-test/suite/funcs_1/r/memory_func_view.result:
Updated results after better cast warnings
mysql-test/suite/funcs_1/r/myisam_func_view.result:
Updated results after better cast warnings
mysql-test/suite/optimizer_unfixed_bugs/t/bug43448.test:
Added begin...commit to speed up test.
mysql-test/suite/parts/inc/part_supported_sql_funcs_delete.inc:
Added begin...commit to speed up test.
mysql-test/suite/parts/inc/partition_supported_sql_funcs.inc:
Added begin...commit to speed up test.
mysql-test/suite/parts/r/part_supported_sql_func_innodb.result:
Added begin...commit to speed up test.
mysql-test/suite/parts/r/part_supported_sql_func_myisam.result:
Added begin...commit to speed up test.
mysql-test/suite/parts/r/rpl_partition.result:
Added begin...commit to speed up test.
mysql-test/suite/parts/t/part_supported_sql_func_innodb.test:
Removed duplicated --big_test
mysql-test/suite/parts/t/rpl_partition.test:
Added begin...commit to speed up test.
mysql-test/suite/pbxt/r/cast.result:
Updated results after better cast warnings
mysql-test/suite/pbxt/r/func_str.result:
Updated results after better cast warnings
mysql-test/suite/pbxt/r/type_newdecimal.result:
Updated results after better cast warnings
mysql-test/suite/rpl/r/rpl_innodb_bug28430.result:
Added begin...commit to speed up test.
mysql-test/suite/rpl/t/rpl_innodb_bug28430.test:
Added begin...commit to speed up test.
mysql-test/suite/vcol/r/vcol_supported_sql_funcs_innodb.result:
More warnings
mysql-test/suite/vcol/r/vcol_supported_sql_funcs_myisam.result:
More warnings
mysql-test/t/cast.test:
A lot of new cast() tests
mysql-test/t/strict.test:
Added new test
mysys/CMakeLists.txt:
Added ma_dyncol.c
mysys/Makefile.am:
Added ma_dyncol.c
mysys/string.c:
Added dynstr_reassociate() to move a buffer from dynamic_strings to some other allocator
sql-common/my_time.c:
Added 'fuzzydate' flag to str_to_time()
Added support for microseconds to my_time_to_str() and my_datetime_to_str()
Reset second_parts in number_to_datetime()
Added double_to_datetime()
sql/field.cc:
Added double_to_longlong() and truncate_double() to simplify and reuse code
sql/field.h:
New prototypes
sql/item.cc:
Changed Item::get_date(MYSQL_TIME *ltime,uint fuzzydate) to be aware of type of argument.
(Needed to make it microsecond safe and get better warnings).
Updated call to str_to_time_with_warn()
sql/item.h:
Added struct st_dyncall_create_def used by dynamic columns
Added virtual bool dynamic_result() to tell if type of argument may change over calls.
sql/item_cmpfunc.cc:
Added Item_func_dyncol_exists()
sql/item_cmpfunc.h:
Added class Item_func_dyncol_exists
sql/item_create.cc:
Added get_length_and_scale() to simplify other functions
Simplified and extended create_func_cast()
Added support for cast(X as double(X,Y))
Added functions to create dynamic column functions.
sql/item_create.h:
Added prototypes
sql/item_func.cc:
Extended cast functions Item_func_signed() and Item_func_unsigned() to work with dynamic types
Added Item_double_typecast()
sql/item_func.h:
Added class Item_double_typecast()
sql/item_strfunc.cc:
Added functions for COLUMN_CREATE(), COLUMN_ADD(), COLUMN_GET() and COLUMN_LIST()
sql/item_strfunc.h:
Added classes for COLUMN_CREATE(), COLUMN_ADD(), COLUMN_GET() and COLUMN_LIST()
sql/item_timefunc.cc:
Added flag argument to str_to_time_with_warn()
Updated Item_char_typecast() to handle result type that may change between calls (for dynamic columns)
Added Item_time_typecast::get_date() to ensure that we cast a datetime to time properly.
sql/item_timefunc.h:
Added get_date() to Item_time_typecast() to allow proper results for casting time to datetime
sql/lex.h:
Added new SQL function names
sql/my_decimal.cc:
Added 'const' to some arguments.
Better error message in case of errors (we now print out the wrong value)
Added my_decimal2int()
sql/my_decimal.h:
Moved some constants to my_decimal_limits.h
Updated prototypes.
Made my_decimal2int() a function as it's rather long (no reason to have it inline)
Added decimal2my_decimal() function.
sql/mysql_priv.h:
Prototypes for new functions
sql/share/errmsg.txt:
New error messages for wrong casts and dynamic columns
sql/sql_acl.cc:
Fixed indentation
sql/sql_base.cc:
Added dynamic_column_error_message()
sql/sql_string.h:
Added reassociate() to move a buffer to be owned by String object.
sql/sql_yacc.yy:
Added syntax for COLUMN_ functions.
sql/time.cc:
Updated str_to_datetime_with_warn() flag argument to same type as other functions
Added conversion flag to str_to_time_with_warn() (Similar to all datetime functions)
Added conversion functions with warnings: double_to_datetime_with_warn() and decimal_to_datetime_with_warn()
strings/decimal.c:
Added 'const' to arguments for some functions.
unittest/mysys/Makefile.am:
Added test for dynamic columns code
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.
Both these two bugs happened due to the following problem.
When a view column is referenced in the query an Item_direct_view_ref
object is created that is refers to the Item_field for the column.
All references to the same view column refer to the same Item_field.
Different references can belong to different AND/OR levels and,
as a result, can be included in different Item_equal object.
These Item_equal objects may include different constant objects.
If these constant objects are substituted for the Item_field created
for a view column we have a conflict situation when the second
substitution annuls the first substitution. This leads to
wrong result sets returned by the query. Bug #724942 demonstrates
such an erroneous behaviour.
Test case of the bug #717577 produces wrong result sets because best
equal fields of the multiple equalities built for different OR levels
of the WHERE condition differs. The subsitution for the best equal field
in the second OR branch overwrites the the substitution made for the
first branch.
To avoid such conflicts we have to substitute for the references
to the view columns rather than for the underlying field items.
To make such substitutions possible we have to include into
multiple equalities references to view columns rather than
field items created for such columns.
This patch modifies the Item_equal class to include references
to view columns into multiple equality objects. It also performs
a clean up of the class methods and adds more comments. The methods
of the Item_direct_view_ref class that assist substitutions for
references to view columns has been also added by this patch.
Valgrind warning happens due to early null values check
in Item_func_in::fix_length_and_dec(before item evaluation).
As result null value items with uninitialized values are
placed into array and it leads to valgrind warnings during
value array sorting.
The fix is to check null value after item evaluation, item
is evaluated in in_array::set() method.
mysql-test/r/func_in.result:
test case
mysql-test/t/func_in.test:
test case
sql/item_cmpfunc.cc:
The fix is to check null value after item evaluation.
Analysis:
A query with implicit grouping is one with aggregate functions and
no GROUP BY clause. MariaDB inherits from MySQL an SQL extenstion
that allows mixing aggregate functions with non-aggregate fields.
If a query with such mixed select clause produces an empty result
set, the meaning of aggregate functions is well defined - either
NULL (MIN, MAX, etc.), or 0 (count(*)). However the non-aggregated
fields must also have some value, and the only reasonable value in
the case of empty result is NULL.
The cause of the many wrong results was that if a field is declared
as non-nullable (e.g. because it is a PK or NOT NULL), the semantic
analysis and the optimization phases treat this field as non-nullable,
and generate all related query plan elements based on this assumption.
Later during execution, these incorrectly configured/generated query
plan elements result in a wrong result because the selected fields
are not null due to the not-null assumption during optimization.
Solution:
Detect before the context analysys phase that a query uses implicit
grouping with mixed aggregates/non-aggregates, and set all fields
as nullable. The parser already walks the SELECT clause, and
already sets Item::with_sum_func for Items that reference aggreagate
functions. The patch adds a symmetric Item::with_field so that all
Items that reference an Item_field are marked during their
construction at parse time in the same way as with aggregate function
use.
many changes:
* NOT_FIXED_DEC now create hires fields, not old ones.
As a result, temp tables preserve microseconds (on DISTINCT, GROUP BY)
* I_S tables force decimals=0 on temporal types (backward compatibility)
* Item_func_coalesce calculates decimals for temporal types
* no precision for TIME/DATETIME in CAST means 0, not NOT_FIXED_DEC
* addtime/timediff calculate decimals from arguments (not NOT_FIXED_DEC)
sql/field.h:
NOT_FIXED_DEC now create hires fields, not old ones
sql/item.h:
force decimals=0 for I_S tables
sql/item_cmpfunc.cc:
Item_func_coalesce calculates decimals for temporal types
sql/item_create.cc:
no precision for TIME/DATETIME in CAST means 0, not NOT_FIXED_DEC
sql/item_timefunc.cc:
addtime calculates decimals from arguments (not NOT_FIXED_DEC)
sql/item_timefunc.h:
timediff calculates decimals from arguments (not NOT_FIXED_DEC)
