and HAVING
When calculating GROUP BY the server caches some expressions. It does
that by allocating a string slot (Item_copy_string) and assigning the
value of the expression to it. This effectively means that the result
type of the expression can be changed from whatever it was to a string.
As this substitution takes place after the compile-time result type
calculation for IN but before the run-time type calculations,
it causes the type calculations in the IN function done at run time
to get unexpected results different from what was prepared at compile time.
In the CASE ... WHEN ... THEN ... statement there was a similar problem
and it was solved by artificially adding a STRING argument to the matrix
at compile time, so if any of the arguments of the CASE function changes
its type to a string it will still be covered by the information prepared
at compile time.
Extended the CASE fix for cover the IN case.
An alternative way of fixing this problem is by caching the result type of
the arguments at compile time and using the cached information at run time
instead of re-calculating the result types.
Preferred the CASE approach for uniformity and fix localization.
BUG#42101 - Race condition in innodb_commit_concurrency
Detailed revision comments:
r4994 | marko | 2009-05-14 15:04:55 +0300 (Thu, 14 May 2009) | 18 lines
branches/5.1: Prevent a race condition in innobase_commit() by ensuring
that innodb_commit_concurrency>0 remains constant at run time. (Bug #42101)
srv_commit_concurrency: Make this a static variable in ha_innodb.cc.
innobase_commit_concurrency_validate(): Check that innodb_commit_concurrency
is not changed from or to 0 at run time. This is needed, because
innobase_commit() assumes that innodb_commit_concurrency>0 remains constant.
Without this limitation, the checks for innodb_commit_concurrency>0
in innobase_commit() should be removed and that function would have to
acquire and release commit_cond_m at least twice per invocation.
Normally, innodb_commit_concurrency=0, and introducing the mutex operations
would mean significant overhead.
innodb_bug42101.test, innodb_bug42101-nonzero.test: Test cases.
rb://123 approved by Heikki Tuuri
Problem: executing queries like "ALTER TABLE view1;" we don't
check new view's name (which is not specified),
that leads to server crash.
Fix: do nothing (to be consistent with the behaviour for tables)
in such cases.
Problem: using LOAD_FILE() in some cases we pass a file name string
without a trailing '\0' to fn_format() which relies on that however.
That may lead to valgrind warnings.
Fix: add a trailing '\0' to the file name passed to fn_format().
The problem is that the internal variable used to specify a
transaction with consistent read was being used outside the
processing context of a START TRANSACTION WITH CONSISTENT
SNAPSHOT statement. The practical consequence was that a
consistent snapshot specification could leak to unrelated
transactions on the same session.
The solution is to ensure a consistent snapshot clause is
only relied upon for the START TRANSACTION statement.
This is already fixed in a similar way on 6.0.
SQL_SELECT::test_quick_select
The crash was caused by an incomplete cleanup of JOIN_TAB::select
during the filesort of rows for GROUP BY clause inside a subquery.
Queries where a quick index access is replaced with filesort was
was affected. For example:
SELECT 1 FROM
(SELECT COUNT(DISTINCT c1) FROM t1
WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x
Quick index access related data in the SQL_SELECT::test_quick_select
function was inconsistent after an incomplete cleanup.
This function has been completed to prevent crashes in the
SQL_SELECT::test_quick_select function.
Problem: storing "SELECT ... INTO @var ..." results in variables we used val_xxx()
methods which returned results of the current row.
So, in some cases (e.g. SELECT DISTINCT, GROUP BY or HAVING) we got data
from the first row of a new group (where we evaluate a clause) instead of
data from the last row of the previous group.
Fix: use val_xxx_result() counterparts to get proper results.
The --hexdump option crashed mysqlbinlog when used together
with the --read-from-remote-server option due to use of
uninitialized memory.
Since Log_event::print_header() relies on temp_buf to be
initialized when the --hexdump option is present,
dump_remote_log_entries() was fixed to setup temp_buf to point
to the start of a binlog event as done in
dump_local_log_entries().
The root cause of this bug is identical to the one for
bug #17654. The latter was fixed in 5.1 and up, so this
patch is backport of the patches for bug #17654 to 5.0.
Only 5.0 needs a changelog entry.
Details:
innodb-autoinc-optimize
Add DROP TABLE which is missing (Backport of fix from 5.1)
innodb_notembedded
Take care that the disconnects of additional sessions
are completed.
Note:
The merge 5.0 -> 5.1 for innodb-autoinc-optimize
should be a "null" merge = no changes in 5.1.
with seg fault
Multiple-table DELETE from a table joined to itself may cause
server crash. This was originally discovered with MEMORY engine,
but may affect other engines with different symptoms.
The problem was that the server violated SE API by performing
parallel table scan in one handler and removing records in
another (delete on the fly optimization).
Certain multi-updates gave different results on InnoDB from
to MyISAM, due to on-the-fly updates being used on the former and
the update order matters.
Fixed by turning off on-the-fly updates when update order
dependencies are present.
on cp932 and sjis environment.
Problem: case conversion erroneously changes the second bytes
of multi-byte sequences because single-byte functions were
called in a mistake.
Fix: call multi-byte aware functions instead.
'INSERT ... SELECT' statements
The code that produces result rows expected that a duplicate row
error could not occur in INSERT ... SELECT statements with
unfulfilled WHERE conditions. This may happen, however, if the
SELECT list contains only aggregate functions.
Fixed by checking if an error occured before trying to send EOF
to the client.
EXPLAIN EXTENDED of nested query containing a error:
1054 Unknown column '...' in 'field list'
may cause a server crash.
Parse error like described above forces a call to
JOIN::destroy() on malformed subquery.
That JOIN::destroy function closes and frees temporary
tables. However, temporary fields of these tables
may be listed in st_select_lex::group_list of outer
query, and that st_select_lex may not cleanup them
properly. So, after the JOIN::destroy call that
st_select_lex::group_list may have Item_field
objects with dangling pointers to freed temporary
table Field objects. That caused a crash.
This patch adds corrections to the original patch
submitted 2009-04-08 (http://lists.mysql.com/commits/71607):
- fixed that the original patch didn't work because of an
incorrect condition;
- added a test case.
Error happens because sp_head::MULTI_RESULTS is not set for SP
which has 'show table status' command.
The fix is to add a SQLCOM_SHOW_TABLE_STATUS case into
sp_get_flags_for_command() func.
Killing the insert-select statement corrupts the MyISAM table only
when the destination table is empty and when it has indexes. When
we bulk insert huge data and if the destination table is empty we
disable the indexes for fast inserts, data is then inserted and
indexes are re-enabled after bulk_insert operation
Killing the query, aborts the repair table operation during enable
indexes phase leading to table corruption.
We now truncate the table when we detect that enable indexes is
killed for bulk insert query.As we have an empty table before the
operation, we can fix by truncating the table.
A bug in the initialization of key segment information made it point
to the wrong bit, since a bit index was used when its int value
was needed. This lead to misinterpretation of bit columns
read from MyISAM record format when a NULL bit pushed them over
a byte boundary.
Fixed by using the int value of the bit instead.
