of untouched rows in full table scans".
SELECT ... FOR UPDATE/LOCK IN SHARE MODE statements as well as
UPDATE/DELETE statements which were executed using full table
scan were not releasing locks on rows which didn't satisfy
WHERE condition.
This bug surfaced in 5.0 and affected NDB tables. (InnoDB tables
intentionally don't support such unlocking in default mode).
This problem occured because code implementing join didn't call
handler::unlock_row() for rows which didn't satisfy part of condition
attached to this particular table/level of nested loop. So we solve
the problem adding this call.
Note that we already had this call in place in 4.1 but it was lost
(actually not quite correctly placed) when we have introduced nested
joins.
Also note that additional QA should be requested once this patch is
pushed as interaction between handler::unlock_row() and many recent
MySQL features such as subqueries, unions, views is not tested enough.
aliases ignored
When a column reference to a column in JOIN USING is resolved and a new
Item is created for this column the user defined name was lost.
This fix preserves the alias by setting the name of the new Item to the
original alias.
In the method Item_field::fix_fields we try to resolve the name of
the field against the names of the aliases that occur in the select
list. This is done by a call of the function find_item_in_list.
When this function finds several occurrences of the field name
it sends an error message to the error queue and returns 0.
Yet the code did not take into account that find_item_in_list
could return 0 and tried to dereference the returned value.
used.
The Item::save_in_field() function is called from fill_record() to fill the
new row with data while execution of the CREATE TABLE ... SELECT statement.
Item::save_in_field() calls val_xxx() methods in order to get values.
val_xxx() methods do not take into account the result field. Due to this
Item_func_set_user_var::val_xxx() methods returns values from the original
table, not from the temporary one.
The save_in_field() member function is added to the Item_func_set_user_var
class. It detects whether the result field should be used and properly updates
the value of the user variable.
A BINARY field is represented by the Field_string class. The space character
is used as the filler for unused characters in such a field. But a BINARY field
should use \x00 instead.
Field_string:reset() now detects whether the current field is a BINARY one
and if so uses the \x00 character as a default value filler.
correctly in some cases".
In short, calls to a stored function located in another database
than the default database, may fail to replicate if the call was made
by SET, SELECT, or DO.
Longer: when a stored function is called from a statement which does not go
to binlog ("SET @a=somedb.myfunc()", "SELECT somedb.myfunc()",
"DO somedb.myfunc()"), this crafted statement is binlogged:
"SELECT myfunc();" (accompanied with a mention of the default database
if there is one). So, if "somedb" is not the default database,
the slave would fail to find myfunc(). The fix is to specify the
function's database name in the crafted binlogged statement, like this:
"SELECT somedb.myfunc();". Test added in rpl_sp.test.
The optimizer removes expressions from GROUP BY/DISTINCT
if they happen to participate in a <expression> = <const>
predicates of the WHERE clause (the idea being that if
it's always equal to a constant it can't have multiple
values).
However for predicates where the expression and the
constant item are of different result type this is not
valid (e.g. a string column compared to 0).
Fixed by additional check of the result types of the
expression and the constant and if they differ the
expression don't get removed from the group by list.
This bug appeared after the patch for bug 21390 that had added some code
to handle outer joins with no matches after substitution of a const
table in an efficient way. That code as it is cannot be applied to the case
of nested outer join operations. Being applied to the queries with
nested outer joins the code can cause crashes or wrong result sets.
The fix blocks row substitution for const inner tables of an outer join
if the inner operand is not a single table.
With MySQL 3.23 and 4.0, the syntax 'LIMIT N, -1' is accepted, and returns
all the rows located after row N. This behavior, however, is not the
intended result, and defeats the purpose of LIMIT, which is to constrain
the size of a result set.
With MySQL 4.1 and later, this construct is correctly detected as a syntax
error.
This fix does not change the production code, and only adds a new test case
to improve test coverage in this area, to enforce in the test suite the
intended behavior.
repair it
Multi-table delete that is optimized with QUICK_RANGE reports table
corruption.
DELETE statement must not use KEYREAD optimization, and sets
table->no_keyread to 1. This was ignored in QUICK_RANGE optimization.
With this fix QUICK_RANGE optimization honors table->no_keyread
value and does not enable KEYREAD when it is requested.
When only one row was present, the subtraction of nearly the same number
resulted in catastropic cancellation, introducing an error in the
VARIANCE calculation near 1e-15. That was sqrt()ed to get STDDEV, the
error was escallated to near 1e-8.
The simple fix of testing for a row count of 1 and forcing that to yield
0.0 is insufficient, as two rows of the same value should also have a
variance of 0.0, yet the error would be about the same.
So, this patch changes the formula that computes the VARIANCE to be one
that is not subject to catastrophic cancellation.
In addition, it now uses only (faster-than-decimal) floating point numbers
to calculate, and renders that to other types on demand.
