IS NULL was not checking the correct row in a HAVING context.
At the first row of a new group (where the HAVING clause is evaluated)
the column and SELECT list references in the HAVING clause should
refer to the last row of the previous group and not to the current one.
This was not done for IS NULL, because it was using Item::is_null() doesn't
have a Item_is_null_result() counterpart to access the data from the
last row of the previous group. Note that all the Item::val_xxx() functions
(e.g. Item::val_int()) have their _result counterparts (e.g. Item::val_int_result()).
Fixed by implementing a is_null_result() (similarly to int_result()) and
calling this instead of is_null() column and SELECT list references inside
the HAVING clause.
min() and max() functions are implemented in MySQL as macros.
This means that max(a,b) is expanded to: ((a) > (b) ? (a) : (b))
Note how 'a' is quoted two times.
Now imagine 'a' is a recursive function call that's several 10s of levels deep.
And the recursive function does max() with a function arg as well to dive into
recursion.
This means that simple function call can take most of the clock time.
Identified and fixed several such calls to max()/min() : including the IF()
sql function implementation.
The problem is that passing anything other than a integer to a limit
clause in a prepared statement would fail. This limitation was introduced
to avoid replication problems (e.g: replicating the statement with a
string argument would cause a parse failure in the slave).
The solution is to convert arguments to the limit clause to a integer
value and use this converted value when persisting the query to the log.
Problem: SLEEP(0) never returns on 64-bit Mac OS X due to a bug in
pthread_cond_timedwait().
Fix: when given a very short timeout just return immediately.
Simple subselects are pulled into upper selects. This operation substitutes the
pulled subselect for the first item from the select list of the subselect.
If an alias is defined for a subselect it is inherited by the replacement item.
As this is done after fix_fields phase this alias isn't showed if the
replacement item is a stored function. This happens because the Item_func_sp::make_field
function makes send field from its result_field and ignores the defined alias.
Now when an alias is defined the Item_func_sp::make_field function sets it for
the returned field.
The ROUND(X, D) function would change the Item::decimals field during
execution to achieve the effect of a dynamic number of decimal digits.
This caused a series of bugs:
Bug #30617:Round() function not working under some circumstances in InnoDB
Bug #33402:ROUND with decimal and non-constant cannot round to 0 decimal places
Bug #30889:filesort and order by with float/numeric crashes server
Fixed by never changing the number of shown digits for DECIMAL when
used with a nonconstant number of decimal digits.
There's currently no way of knowing the determinicity of an UDF.
And the optimizer and the sequence() UDFs were making wrong
assumptions about what the is_const member means.
Plus there was no implementation of update_system_tables()
causing the optimizer to overwrite the information returned by
the <udf>_init function.
Fixed by equating the assumptions about the semantics of
is_const and providing a implementation of update_used_tables().
Added a TODO item for the UDF API change needed to make a better
implementation.
Sending several "KILL QUERY" statements to target a connection running
"SELECT SLEEP" could freeze the server.
The locking order in Item_func_sleep was wrong and this could lead to a
dead lock.
This patch solves the issue by resolving the locking order properly.
There are two problems with ROUND(X, D) on an exact numeric
(DECIMAL, NUMERIC type) field of a table:
1) The implementation of the ROUND function would change the number of decimal
places regardless of the value decided upon in fix_length_and_dec. When the
number of decimal places is not constant, this would cause an inconsistent
state where the number of digits was less than the number of decimal places,
which crashes filesort.
Fixed by not allowing the ROUND operation to add any more decimal places than
was decided in fix_length_and_dec.
2) fix_length_and_dec would allow the number of decimals to be greater than
the maximium configured value for constant values of D. This led to the same
crash as in (1).
Fixed by not allowing the above in fix_length_and_dec.
ucs2 doesn't provide required by fulltext ctype array. Crash
happens because fulltext attempts to use unitialized ctype
array.
Fixed by converting ucs2 fields to compatible utf8 analogue.
Previously, UDF *_init functions were passed constant strings with erroneous lengths. The length came from the containing variable's size, not the length of the value itself.
Now the *_init functions get the constant as a null terminated string with the correct length supplied too.
This actually, fix for the patch for bug-27354. The problem with
the patch was that Item_func_sp::used_tables() was updated, but
Item_func_sp::const_item() was not. So, for Item_func_sp, we had
the following inconsistency:
- used_tables() returned RAND_TABLE, which means that the item
can produce "random" results;
- but const_item() returned TRUE, which means that the item is
a constant one.
The fix is to change Item_func_sp::const_item() behaviour: it must
return TRUE (an item is a constant one) only if a stored function
is deterministic and each of its arguments (if any) is a constant
item.
When calculating the result length of an integer DIV function
the number of decimals was used without checking the result type
first. Thus an uninitialized number of decimals was used for some
types. This caused an excessive amount of memory to be allocated
for the field's buffer and crashed the server.
Fixed by using the number of decimals only for data types that
can have decimals and thus have valid decimals number.
type of the result.
There are several functions that accept parameters of different types.
The result field type of such functions was determined based on
the aggregated result type of its arguments. As the DATE and the DATETIME
types are represented by the STRING type, the result field type
of the affected functions was always STRING for DATE/DATETIME arguments.
The affected functions are COALESCE, IF, IFNULL, CASE, LEAST/GREATEST, CASE.
Now the affected functions aggregate the field types of their arguments rather
than their result types and return the result of aggregation as their result
field type.
The cached_field_type member variable is added to the number of classes to
hold the aggregated result field type.
The str_to_date() function's result field type now defaults to the
MYSQL_TYPE_DATETIME.
The agg_field_type() function is added. It aggregates field types with help
of the Field::field_type_merge() function.
The create_table_from_items() function now uses the
item->tmp_table_field_from_field_type() function to get the proper field
when the item is a function with a STRING result type.
(Regression, caused by a patch for the bug 22646).
Problem: when result type of date_format() was changed from
binary string to character string, mixing date_format()
with a ascii column in CONCAT() stopped to work.
Fix:
- adding "repertoire" flag into DTCollation class,
to mark items which can return only pure ASCII strings.
- allow character set conversion from pure ASCII to other character sets.
Problem: thd->thread_specific_used flag is not set executing a statement
containig connection_id() function using PS protocol, that leads to
improper binlog event creation.
Fix: set the flag in the Item_func_connection_id::fix_fields().
restores from mysqlbinlog out
Problem: using "mysqlbinlog | mysql" for recoveries the connection_id()
result may differ from what was used when issuing the statement.
Fix: if there is a connection_id() in a statement, write to binlog
SET pseudo_thread_id= XXX; before it and use the value later on.
Optimization of queries with DETERMINISTIC functions in the
WHERE clause was not effective: sequential scan was always
used.
Now a SF with the DETERMINISTIC flags is treated as constant
when it's arguments are constants (or a SF doesn't has arguments).
DECIMAL column was used instead of BIGINT for the minimal possible
BIGINT (-9223372036854775808).
The Item_func_neg::fix_length_and_dec has been adjusted to
to inherit the type of the argument in the case when it's an
Item_int object whose value is equal to LONGLONG_MIN.
of its arguments was evaluated to NULL, while the predicate
LOCATE(str,NULL) IS NULL erroneously was evaluated to FALSE.
This happened because the Item_func_locate::fix_length_and_dec
method by mistake set the value of the maybe_null flag for
the function item to 0. In consequence of this the function
was considered as the one that could not ever return NULL.
was erroneously converted to double, while the result of
ROUND(<decimal expr>, <int literal>) was preserved as decimal.
As a result of such a conversion the value of ROUND(D,A) could
differ from the value of ROUND(D,val(A)) if D was a decimal expression.
Now the result of the ROUND function is never converted to
double if the first argument is decimal.
- fixed wrong test case for bug 20903
- closed the dangling connections in trigger.test
- GET_LOCK() and RELEASE_LOCK() now produce more detailed log
- fixed an omission in GET_LOCK() : assign the thread_id when
acquiring the lock.
This is an additional fix.
Item::val_xxx methods are supposed to use original data source and
Item::val_xxx_result methods to use the item's result field. But for the
Item_func_set_user_var class val_xxx_result methods were mapped to val_xxx
methods. This leads, in particular, to producing bad sort keys and thus
wrong order of the result set of queries with group by/order by clauses.
The set of val_xxx_result methods is added to the Item_func_set_user_var
class. It's the same as the val_xxx set of method but uses the result_field
to return a value.
The end_update() function uses the Item::save_org_in_field() function to
save original values of items into the group buffer. But for the
Item_func_set_user_var this method was mapped to the save_in_field method.
The latter function wrongly decides to use the result_field. This leads to
saving incorrect value in the grouping buffer and wrong result of the whole
query.
The can_use_result_field argument of the bool type is added to the
Item_func_set_user_var::save_in_field() function. If it is set to FALSE
then the item's result field won't be used. Otherwise it will be detected
whether the result field will be used (old behaviour).
Two wrapping functions for the function above are added to the
Item_func_set_user_var class:
the save_in_field(Field *field, bool no_conversions) - it calls the above
function with the can_use_result_field set to TRUE.
the save_org_in_field(Field *field) - same, but the can_use_result_field
is set to FALSE.
longer showing SP names.
SHOW CREATE VIEW uses Item::print() methods to reconstruct the
statement text from the parse tree.
The print() method for stored procedure calls needs allocate
space to print the function's quoted name.
It was incorrectly calculating the length of the buffer needed
(was too short).
Fixed to reflect the actual space needed.
If a stored function or a trigger was killed it had aborted but no error
was thrown. This allows the caller statement to continue without a notice.
This may lead to a wrong data being inserted/updated to/deleted as in such
cases the correct result of a stored function isn't guaranteed. In the case
of triggers it allows the caller statement to ignore kill signal and to
waste time because of re-evaluation of triggers that always will fail
because thd->killed flag is still on.
Now the Item_func_sp::execute() and the sp_head::execute_trigger() functions
check whether a function or a trigger were killed during execution and
throws an appropriate error if so.
Now the fill_record() function stops filling record if an error was reported
through thd->net.report_error.
