Analysis:
There are two code paths through which JOIN::exec may produce
an all-NULL row for an empty result set. One goes via the
function return_zero_rows(), when query processing detectes
early that the where clause is false, the other one is via
do_select() in the case of join execution.
In the case of do_select(), the problem was that the executioner
didn't set TABLE::null_row to 1. As result when sending the only
result row, the evaluation of each field didn't detect that all
non-aggregated fields are NULL, because Field::is_null returned
true, after checking that field->table->null_row was false.
Given that the each non-aggregated field was not considered NULL,
select_result::send_data sent whatever was in the buffer of each
field. However, since there was no actual data in the field buffer,
send_data() accessed and sent whatever junk was in the field's
data buffer.
Solution:
Similar to the analogous case in return_zero_rows() mark all
tables that their current row is NULL before sending the
artificailly created NULL row.
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.
mysql-test/r/union.result:
Added test for lp:732124
mysql-test/t/union.test:
Added test for lp:732124
sql/sp_rcontext.cc:
Updated function definition for ::send_data()
sql/sp_rcontext.h:
Updated function definition for ::send_data()
sql/sql_analyse.cc:
Test if send_data() returned an error
sql/sql_class.cc:
Updated function definition for ::send_data()
sql/sql_class.h:
Changed select_result::send_data(List<Item> &items) to return -1 in case of duplicate row that should not be counted as part of LIMIT
sql/sql_cursor.cc:
Check if send_data returned error
sql/sql_delete.cc:
Updated function definition for ::send_data()
sql/sql_insert.cc:
Updated function definition for ::send_data()
sql/sql_select.cc:
Don't count rows which send_data() tells you to ignore
sql/sql_union.cc:
Inform caller that the row should be ignored. This is the real bug fix for lp:732124
sql/sql_update.cc:
Updated function definition for ::send_data()
This allows us to simplify and speed up some tests and also remove get_cached_item()
sql/item.h:
Added item.real_type()
Removed get_cached_item()
sql/opt_range.cc:
Simplify test
sql/sql_select.cc:
Simplify test
sql/sql_show.cc:
Simplify test
If join condition is of the form <t2.key>=<t1.no_key> then the server
performs no index look-ups when looking for matching rows of t2 for
the rows from t1 with t1.no_key=NULL. It happens because the function
add_not_null_conds() injects an additional condition of the form
IS NOT NULL(<t1.no_key>) into the WHERE condition.
However if the join condition was of the form <t.key>=<outer_ref> no
additional null rejecting predicate was generated. This could lead
to extra records in the result set if the value of <outer_ref> happened
to be NULL.
The new code injects null rejecting predicates of the form
IS NOT NULL(<outer_ref>) and evaluates them before the first row
the subquery is constructed.
- put the code that sets HA_NULL_PART bit back
- Fix test_if_ref/part_of_refkey() so that
= NULL-ability of lookup columns does not prevent the equality
from being removed (we now have early/late NULLs filtering which
will filter out NULL values)
= equality is not removed if it is ref_or_null access, and the value
of the lookup column can alternate between the lookup value and NULL.
The bug was a result of the fix for bug 668644 that turned out to be
not quite correct. A problem appeared with HAVING conditions containing
more than one predicate. If a query with an ORDER BY clause uses
such HAVING condition and the required order can be obtained with
a range/index scan then the HAVING condition has to be pushed into
two different formulas (items). To be able to do it we have to create
a copy of the ANDOR structure of the pushed condition.
and collateral changes.
* introduce my_hrtime_t, my_timediff_t, and conversion macros
* inroduce TIME_RESULT, but it can only be returned from Item::cmp_type(),
never from Item::result_type()
* pack_time/unpack_time function for "packed" representation of
MYSQL_TIME in a longlong that can be compared
* ADDTIME()/SUBTIME()/+- INTERVAL now work with TIME values
* numbers aren't quoted in EXPLAIN EXTENDED
* new column I_S.COLUMNS.DATETIME_PRECISION
* date/time values are compares to anything as date/time, not as strings or numbers.
* old timestamp(X) is no longer supported
* MYSQL_TIME to string conversion functions take precision as an argument
* unified the warnings from Field_timestamp/datetime/time/date/newdate store methods
* Field_timestamp_hires, Field_datetime_hires, Field_time_hires
* Field_temporal
* Lazy_string class to pass a value (string, number, time) polymorphically down the stack
* make_truncated_value_warning and Field::set_datetime_warning use Lazy_string as an argument, removed char*/int/double variants
* removed Field::can_be_compared_as_longlong(). Use Field::cmp_type() == INT_RESULT instead
* introduced Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
* in many cases date/time types are treated like other types, not as special cases
* greatly simplified Arg_comparator (regarding date/time/year code)
* SEC_TO_TIME is real function, not integer.
* microsecond precision in NOW, CURTIME, etc
* Item_temporal. All items derived from it only provide get_date, but no val* methods
* replication of NOW(6)
* Protocol::store(time) now takes the precision as an argument
* @@TIMESTAMP is a double
client/mysqlbinlog.cc:
remove unneded casts
include/my_sys.h:
introduce my_hrtime_t, my_timediff_t, and conversion macros
include/my_time.h:
pack_time/unpack_time, etc.
convenience functions to work with MYSQL_TIME::second_part
libmysql/libmysql.c:
str_to_time() is gone. str_to_datetime() does it now.
my_TIME_to_str() takes the precision as an argument
mysql-test/include/ps_conv.inc:
time is not equal to datetime anymore
mysql-test/r/distinct.result:
a test for an old MySQL bug
mysql-test/r/explain.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/func_default.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/func_sapdb.result:
when decimals=NOT_FIXED_DEC it means "not fixed" indeed
mysql-test/r/func_test.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/func_time.result:
ADDTIME()/SUBTIME()/+- INTERVAL now work with TIME values
mysql-test/r/having.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/information_schema.result:
new column I_S.COLUMNS.DATETIME_PRECISION
mysql-test/r/join_outer.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/metadata.result:
TIMESTAMP no longer has zerofill flag
mysql-test/r/range.result:
invalid datetime is not compared with as a string
mysql-test/r/select.result:
NO_ZERO_IN_DATE, etc only affect storage - according to the manual
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/subselect.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/sysdate_is_now.result:
when decimals=NOT_FIXED_DEC it means "not fixed" indeed
mysql-test/r/type_blob.result:
TIMESTAMP(N) is not deprecated
mysql-test/r/type_timestamp.result:
old TIMESTAMP(X) semantics is not supported anymore
mysql-test/r/union.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/varbinary.result:
numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/t/distinct.test:
test for an old MySQL bug
mysql-test/t/func_time.test:
+- INTERVAL now works with TIME values
mysql-test/t/select.test:
typo
mysql-test/t/subselect.test:
only one error per statement, please
mysql-test/t/system_mysql_db_fix40123.test:
old timestamp(X) is no longer supported
mysql-test/t/system_mysql_db_fix50030.test:
old timestamp(X) is no longer supported
mysql-test/t/system_mysql_db_fix50117.test:
old timestamp(X) is no longer supported
mysql-test/t/type_blob.test:
old timestamp(X) is no longer supported
mysql-test/t/type_timestamp.test:
old timestamp(X) is no longer supported
mysys/my_getsystime.c:
functions to get the time with microsecond precision
mysys/my_init.c:
move the my_getsystime.c initialization code to my_getsystime.c
mysys/my_static.c:
no need to make these variables extern
mysys/my_static.h:
no need to make these variables extern
scripts/mysql_system_tables.sql:
old timestamp(X) is no longer supported
scripts/mysql_system_tables_fix.sql:
old timestamp(X) is no longer supported
scripts/mysqlhotcopy.sh:
old timestamp(X) is no longer supported
sql-common/my_time.c:
* call str_to_time from str_to_datetime, as appropriate
* date/time to string conversions take precision as an argument
* number_to_time()
* TIME_to_double()
* pack_time() and unpack_time()
sql/event_data_objects.cc:
cast is not needed
my_datetime_to_str() takes precision as an argument
sql/event_db_repository.cc:
avoid dangerous downcast (because the pointer is
not always Field_timestamp, see events_1.test)
sql/event_queue.cc:
avoid silly double-work for cond_wait
(having an endpoint of wait, subtract the current time to get the timeout,
and use set_timespec() macro to fill in struct timespec, by adding the current
time to the timeout)
sql/field.cc:
* remove virtual Field::get_time(), everyone should use only Field::get_date()
* remove lots of #ifdef WORDS_BIGENDIAN
* unified the warnings from Field_timestamp/datetime/time/date/newdate store methods
* Field_timestamp_hires, Field_datetime_hires, Field_time_hires
* Field_temporal
* make_truncated_value_warning and Field::set_datetime_warning use Lazy_string as an argument, removed char*/int/double variants
sql/field.h:
* remove virtual Field::get_time(), everyone should use only Field::get_date()
* remove lots of #ifdef WORDS_BIGENDIAN
* unified the warnings from Field_timestamp/datetime/time/date/newdate store methods
* Field_timestamp_hires, Field_datetime_hires, Field_time_hires
* Field_temporal
* make_truncated_value_warning and Field::set_datetime_warning use Lazy_string as an argument, removed char*/int/double variants
* removed Field::can_be_compared_as_longlong(). Use Field::cmp_type() == INT_RESULT instead
sql/filesort.cc:
TIME_RESULT, cmp_time()
sql/item.cc:
* numbers aren't quoted in EXPLAIN EXTENDED
* Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
* virtual Item::get_time() is gone
* Item_param::field_type() is set correctly
* Item_datetime, for a datetime constant
* time to anything is compared as a time
* Item_cache::print() prints the value is available
* bug fixed in Item_cache_int::val_str()
sql/item.h:
* Item::print_value(), to be used from Item_xxx::print() when needed
* Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
* virtual Item::get_time() is gone
* Item_datetime, for a datetime constant
* better default for cast_to_int_type()
* Item_cache objects now *always* have the field_type() set
sql/item_cmpfunc.cc:
* get_year_value, get_time_value are gone. get_datetime_value does it all
* get_value_a_func, get_value_b_func are gone
* can_compare_as_dates() is gone too, TIME_RESULT is used instead
* cmp_type() instead or result_type() when doing a comparison
* compare_datetime and compate_e_datetime in the comparator_matrix, is_nulls_eq is gone
* Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
sql/item_cmpfunc.h:
greatly simplified Arg_comparator
sql/item_create.cc:
* fix a bug in error messages in CAST
sql/item_func.cc:
Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
mention all possibitiles in switch over Item_result values, or use default:
sql/item_row.h:
overwrite the default cmp_type() for Item_row,
as no MYSQL_TYPE_xxx value corresponds to ROW_RESULT
sql/item_timefunc.cc:
rewrite make_datetime to support precision argument
SEC_TO_TIME is real function, not integer.
many functions that returned temporal values had duplicate code in val_* methods,
some of them did not have get_date() which resulted in unnecessary date->str->date conversions.
Now they all are derived from Item_temporal_func and *only* provide get_date, not val* methods.
many fixes to set decimals (datetime precision) correctly.
sql/item_timefunc.h:
SEC_TO_TIME is real function, not integer.
many functions that returned temporal values had duplicate code in val_* methods,
some of them did not have get_date() which resulted in unnecessary date->str->date conversions.
Now they all are derived from Item_temporal_func and *only* provide get_date, not val* methods.
many fixes to set decimals (datetime precision) correctly.
sql/log_event.cc:
replication of NOW(6)
sql/log_event.h:
replication of NOW(6)
sql/mysql_priv.h:
Lazy_string class to pass a value (string, number, time) polymorphically down the stack.
make_truncated_value_warning() that uses it.
sql/mysqld.cc:
datetime in Arg_comparator::comparator_matrix
sql/opt_range.cc:
cleanup: don't disable warnings before calling save_in_field_no_warnings()
sql/protocol.cc:
Protocol::store(time) now takes the precision as an argument
sql/protocol.h:
Protocol::store(time) now takes the precision as an argument
sql/rpl_rli.cc:
small cleanup
sql/set_var.cc:
SET TIMESTAMP=double
sql/set_var.h:
@@TIMESTAMP is a double
sql/share/errmsg.txt:
precision and scale are unsigned
sql/slave.cc:
replication of NOW(6)
sql/sp_head.cc:
cleanup
sql/sql_class.cc:
support for NOW(6)
sql/sql_class.h:
support for NOW(6)
sql/sql_insert.cc:
support for NOW(6)
sql/sql_select.cc:
use item->cmp_type().
move a comment where it belongs
sql/sql_show.cc:
new column I_S.COLUMNS.DATETIME_PRECISION
sql/sql_yacc.yy:
TIME(X), DATETIME(X), cast, NOW(X), CURTIME(X), etc
sql/time.cc:
fix date_add_interval() to support MYSQL_TIMESTAMP_TIME argument
storage/myisam/ha_myisam.cc:
TIMESTAMP no longer carries ZEROFIELD flag, still we keep MYI file compatible.
strings/my_vsnprintf.c:
warnings
tests/mysql_client_test.c:
old timestamp(X) does not work anymore
datetime is no longer equal to time
- Make equality-substitution-for-ref-access code in JOIN::optimize() treat join_tab->ref.key_copy correctly
(in the way create_ref_for_key() has filled it).
Changed some String.ptr() -> String.c_ptr() for String that are not guaranteed to end with \0
Removed some c_ptr() usage from parameters to functions that takes ptr & length
Use preallocate buffers to avoid calling malloc() for most operations.
sql/event_db_repository.cc:
alias is now a String
sql/event_scheduler.cc:
c_ptr -> c_ptr_safe() to avoid warnings from valgrind.
sql/events.cc:
c_ptr -> c_ptr_safe() to avoid warnings from valgrind.
c_ptr -> ptr() as function takes ptr & length
sql/field.cc:
alias is now a String
sql/field.h:
alias is now a String
sql/ha_partition.cc:
alias is now a String
sql/handler.cc:
alias is now a String
ptr() -> c_ptr() as string is not guaranteed to be \0 terminated
sql/item.cc:
Store error parameter in separarte buffer to ensure correct error message
sql/item_func.cc:
ptr() -> c_ptr_safe() as string is not guaranteed to be \0 terminated
sql/item_sum.h:
Use my_strtod() instead of my_atof() to not have to make string \0 terminated
sql/lock.cc:
alias is now a String
sql/log.cc:
c_ptr() -> ptr() as function takes ptr & length
sql/log_event.cc:
c_ptr_quick() -> ptr() as we only want to get the pointer to String buffer
sql/opt_range.cc:
ptr() -> c_ptr() as string is not guaranteed to be \0 terminated
sql/opt_table_elimination.cc:
alias is now a String
sql/set_var.cc:
ptr() -> c_ptr() as string is not guaranteed to be \0 terminated
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
c_ptr() -> ptr() as function takes ptr & length
Simplify some code.
sql/sp.cc:
c_ptr() -> ptr() as function takes ptr & length
sql/sp_rcontext.cc:
alias is now a String
sql/sql_base.cc:
alias is now a String.
Here we win a realloc() for most alias usage.
sql/sql_class.cc:
Use size descriptor for printf() to avoid accessing bytes outside of buffer
sql/sql_insert.cc:
Change allocation of TABLE as it's now contains a String
_ptr() -> ptr() as function takes ptr & length
sql/sql_load.cc:
Use preallocate buffers to avoid calling malloc() for most operations.
sql/sql_parse.cc:
Use c_ptr_safe() to ensure string is \0 terminated.
sql/sql_plugin.cc:
c_ptr_quick() -> ptr() as function takes ptr & length
sql/sql_select.cc:
alias is now a String
sql/sql_show.cc:
alias is now a String
sql/sql_string.h:
Added move() function to change who owns the string (owner does the free)
sql/sql_table.cc:
alias is now a String
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
sql/sql_test.cc:
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
alias is now a String
sql/sql_trigger.cc:
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
Use field->init() to setup pointers to alias.
sql/sql_update.cc:
alias is now a String
sql/sql_view.cc:
ptr() -> c_ptr_safe() as string is not guaranteed to be \0 terminated
sql/sql_yacc.yy:
r() -> c_ptr() as string is not guaranteed to be \0 terminated
sql/table.cc:
alias is now a String
sql/table.h:
alias is now a String
storage/federatedx/ha_federatedx.cc:
Remove extra 1 byte alloc that is automaticly done by strmake()
Ensure that error message ends with \0
storage/maria/ha_maria.cc:
alias is now a String
storage/myisam/ha_myisam.cc:
alias is now a String
sql/mysqld.cc:
Fixed: optimize_join_buffer_size was missing in the description of possible
options for the optimizer switch.
sql/sql_select.cc:
Fixed: initialization for the field ref_table_rows of the KEYUSE structure was
missing (as a result of a lame merge).
even in the cases when there existed range/index-merge scans that
were cheaper than the full table scan.
This was a defect/bug of the implementation of mwl #128.
Now hash join can work not only with full table scan of the joined
table, but also with full index scan, range and index-merge scans.
Accordingly, in the cases when hash join is used the column 'type'
in the EXPLAINs can contain now 'hash_ALL', 'hash_index', 'hash_range'
and 'hash_index_merge'. If hash join is coupled with a range/index_merge
scan then the columns 'key' and 'key_len' contain info not only on
the used hash index, but also on the indexes used for the scan.
- 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
