ORDER BY primary_key on InnoDB table
Queries that use an InnoDB secondary index to retrieve
data don't need to sort in case of ORDER BY primary key
if the secondary index is compared to constant(s).
They can also skip sorting if ORDER BY contains both the
the secondary key parts and the primary key parts (in
that order).
This is because InnoDB returns the rows in order of the
primary key for rows with the same values of the secondary
key columns.
Fixed by preventing temp table sort for the qualifying
queries.
by long running transaction
On Windows opened files can't be deleted. There was a special
upgraded lock mode (TL_WRITE instead of TL_WRITE_ALLOW_READ)
in ALTER TABLE to make sure nobody has the table opened
when deleting the old table in ALTER TABLE. This special mode
was causing ALTER TABLE to hang waiting on a lock inside InnoDB.
This special lock is no longer necessary as the server is
closing the tables it needs to delete in ALTER TABLE.
Fixed by removing the special lock.
Note that this also reverses the fix for bug 17264 that deals with
another consequence of this special lock mode being used.
The Item_date_typecast::val_int function doesn't reset null_value flag.
This makes all values that follows the first null value to be treated as nulls
and led to a wrong result.
Now the Item_date_typecast::val_int function correctly sets the null_value flag
for both null and non-null values.
a temporary table.
The result string of the Item_func_group_concat wasn't initialized in the
copying constructor of the Item_func_group_concat class. This led to a
wrong charset of GROUP_CONCAT result when the select employs a temporary
table.
The copying constructor of the Item_func_group_concat class now correctly
initializes the charset of the result string.
No test case, since the bug requires a stress case with 30 INSERT DELAYED
threads and 1 killer thread to repeat. The patch is verified
manually.
Review fixes.
The server that is running DELAYED inserts would deadlock itself
or crash under high load if some of the delayed threads were KILLed
in the meanwhile.
The fix is to change internal lock acquisition order of delayed inserts
subsystem and to ensure that
Delayed_insert::table_list::db does not point to volatile memory in some
cases.
For details, please see a comment for sql_insert.cc.
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).
to CHECK TABLE
CHECK/REPAIR TABLE reports "File not found" error when issued
against temporary table.
Fixed by disabling a brunch of code (in case it gets temporary table)
that is responsible for updating frm version as it is not needed
for temporary tables.
when creating table
Federated tables had an artificially low maximum of key length,
because the handler failed to implement a method to return it and
the default value is taked from the prototype handler.
Now, implement that method and return the maximum possible key
length, which is that of InnoDB.
Removed duplicate call to handler::external_lock() when
ALTER TABLE that doesn't need to copy a table (quick
ALTER TABLE) was executed.
Also quick ALTER TABLE doesn't hold LOCK_open anymore when
it enables/disables indexes.
Problem: we may break a multibyte char sequence using a key
reduced to maximum allowed length for a storage engine
(that leads to failed assertion in the innodb code,
see also #17530).
Fix: align truncated key length to multibyte char boundary.
