The problem is that select queries executed concurrently with
a concurrent insert on a MyISAM table could be cached if the
select started after the query cache invalidation but before
the unlock of tables performed by the concurrent insert. This
race could happen because the concurrent insert was failing
to prevent cache of select queries happening at the same time.
The solution is to add a 'uncacheable' status flag to signal
that a concurrent insert is being performed on the table and
that queries executing at the same time shouldn't cache the
results.
connections
The problem is that tables can enter open table cache for a thread without
being properly cleaned up. This can happen if make_join_statistics() fails
to read a const table because of e.g. a deadlock. It does set a member of
TABLE structure to a value it allocates, but doesn't clean-up this setting
on error nor does it set the rest of the members in JOIN to allow for
automatic cleanup.
As a result when such an error occurs and the next statement depends re-uses
the table from the open tables cache it will get it with this
TABLE::reginfo.join_tab pointing to a memory area that's freed.
Fixed by making sure make_join_statistics() cleans up TABLE::reginfo.join_tab
on error.
In case of ROW item each compared pair does not
check if argumet collations can be aggregated and
thus appropiriate item conversion does not happen.
The fix is to add the check and convertion for ROW
pairs.
Cleaned up SQL code in the test.
Needed to move the FLUSH TABLES statement prior to the DROP TABLE t1 to prevent a warning of
Table open on delete and a test fail.
Bug#38435 - LONG Microseconds cause MySQL to fail a CAST to DATETIME or DATE
Parsing of optional microsecond part in datetime did not
fail gracefully when field width was larger than the allowed
six places.
Now handles up to the correct six places, and disregards
any extra digits without messing up what we've already got.
testcase checks are made.
MTR spawns mysqltest to run check-testcase test before and after each testcase
it runs. It can also run check-warnings using mysqltest. Since it happened on PB
that these checks hanged, this patch provides additional feedback to help
investigating such failures:
- mysqltest is modified to give feedback about main steps in execution of a
testcase if run in verbose mode (including connection to the server),
- MTR is modified to run mysqltest in verbose mode when doing check-testcase or
check-warnings. The diagnostic output from mysqltest is preserved so that it is
saved upon test failure.
- Since we are only using the auto cleanup in one place of mtr.pl today, disable the
autocleanup and write our own END handler that clean up the tmpdir only when the process
that created it exits.
- output callstacks from crash using cdb debugger which is part
of "Debugging Tools for Windows". Output other interesting
information - function parameters, possibly source code fragment
and other goodies of "!analyze" cdb extension.
A Query in the MyISAM merge table was crashing
if the index merge algorithm was being used
Index Merge optimization requires the reading of
multiple indexes at the same time. Reading multiple
indexes at once with current SE API means that we
need to have handler instance for each to-be-read
index. This is done by creating clones of the handlers
instances. The clone internally does a open of the handler.
The open for a MERGE engine is handled in the following
phases
1) open parent table
2) generate list of underlying
table
3) attach underlying tables
But the current implementation does only the first
phase (i.e.) open parent table.
The current patch fixes this at the MERGE engine level,
by handling the clone operation within the MERGE engine
rather than in the storage engine API. It opens and
attaches the MyISAM tables on the MyISAM storage engine
interface directly within the MERGE engine. The new MyISAM
table instances, as well as the MERGE clone itself, are not
visible in the table cache. This is not a problem because
all locking is handled by the original MERGE table from which
this is cloned of.
MATCH() function accepts column list as an argument. It was possible to override
this requirement with aliased non-column select expression. Which results in
server crash.
With this fix aliased non-column select expressions are not accepted by MATCH()
function, returning an error.
