The task is to
(a) add a comment on indexes and
(b) increase the maximum length of column, table and the new index comments.
The patch committed on behalf of Yoshinori Matsunobu (Yoshinori.Matsunobu@Sun.COM).
When EXPLAIN EXTENDED tries to print column names, it checks whether the
referenced table is CONST (in which case, the column's value rather than
its name will be printed). If no proper table is reference (i.e. because
a derived table was used that has since gone out of scope), this will fail
spectacularly.
This ports an equivalent of the fix for Bug 43354.
CHECK_FIELD_IGNORE was treated as CHECK_FIELD_ERROR_FOR_NULL;
UPDATE...SET...NULL on NOT NULL fields behaved differently after
a trigger.
Now distinguishes between IGNORE and ERROR_FOR_NULL and save/restores
check-field options.
an INFORMATION_SCHEMA table
When a prepared statement using a merged view containing an information
schema table was executed, a metadata lock of the view was not taken.
This meant that it was possible for concurrent view DDL to execute,
thereby breaking the binary log. For example, it was possible
for DROP VIEW to appear in the binary log before a query using the view.
This also happened when a statement in a stored routine was executed a
second time.
For such views, the information schema table is merged into the view
during the prepare phase (or first execution of a statement in a routine).
The problem was that we took a short cut and were not executing full-blown
view opening during subsequent executions of the statement. As a result,
a metadata lock on the view was not taken to protect the view definition.
This patch resolves the problem by making sure a metadata lock is taken
for views even after information schema tables are merged into them.
Test cased added to view.test.
I found three issues during the analysis:
1. Memory leak caused by temp_buf not being freed;
2. Memory leak caused when handling argv;
3. Conditional jump that depended on unitialized values.
Issue #1
--------
DESCRIPTION: when mysqlbinlog is reading from a remote location
the event temp_buf references the incoming stream (in NET
object), which is not freed by mysqlbinlog explicitly. On the
other hand, when it is reading local binary log, it points to a
temporary buffer that needs to be explicitly freed. For both
cases, the temp_buf was not freed by mysqlbinlog, instead was
set to 0. This clearly disregards the free required in the
second case, thence creating a memory leak.
FIX: we make temp_buf to be conditionally freed depending on
the value of remote_opt. Found out that similar fix is already
in most recent codebases.
Issue #2
--------
DESCRIPTION: load_defaults is called by parse_args, and it
reads default options from configuration files and put them
BEFORE the arguments that are already in argc and argv. This is
done resorting to MEM_ROOT. However, parse_args calls
handle_options immediately after which changes argv. Later when
freeing the defaults, pointers to MEM_ROOT won't match, causing
the memory not to be freed:
void free_defaults(char **argv)
{
MEM_ROOT ptr
memcpy_fixed((char*) &ptr,(char *) argv - sizeof(ptr), sizeof(ptr));
free_root(&ptr,MYF(0));
}
FIX: we remove load_defaults from parse_args and call it
before. Then we save argv with defaults in defaults_argv BEFORE
calling parse_args (which inside can then call handle_options
at will). Actually, found out that this is in fact kind of a
backport for BUG#38468 into 5.1, so I merged in the test case
as well and added error check for load_defaults call.
Fix based on:
revid:zhenxing.he@sun.com-20091002081840-uv26f0flw4uvo33y
Issue #3
--------
DESCRIPTION: the structure st_print_event_info constructor
would not initialize the sql_mode member, although it did for
sql_mode_inited (set to false). This would later raise the
warning in valgrind when printing the sql_mode in the event
header, as this print out is protected by a check against
sql_mode_inited and sql_mode variables. Given that sql_mode was
not initialized valgrind would output the warning.
FIX: we add initialization of sql_mode to the
st_print_event_info constructor.
Table corruption happens during table reading in ha_tina::find_current_row() func.
Field::store() method returns error(true) if stored value is 0.
The fix:
added special case for enum type which correctly processes 0 value.
Additional fix:
INSERT...(default) and INSERT...() have the same behaviour now for enum type.
The problem was that a shared InnoDB row lock was taken when executing
SELECT statements inside a stored function as a part of a transaction
using REPEATABLE READ. This prevented other transactions from updating
the row.
InnoDB uses multi-versioning and consistent nonlocking reads. SELECTs
should therefore not acquire locks and block other transactions
wishing to do updates.
This bug is no longer repeatable with the changes introduced in the scope
of metadata locking.
Test case added to innodb_mysql.test.
The problem is that during temporary table creation uneven bits
are not taken into account for hidden fields. It leads to incorrect
calculation&allocation of null bytes size for table record. And
if grouped value is null we set wrong bit for this value(see end_update()).
Fixed by adding separate calculation of uneven bit for hidden fields.
If a prepared statement used both a MyISAMMRG table and a stored
function or trigger, execution could fail with "No such table"
error or crash.
The error would come from a failure of the MyISAMMRG engine
to meet the expectations of the prelocking algorithm,
in particular maintain lex->query_tables_own_last pointer
in sync with lex->query_tables_last pointer/the contents
of lex->query_tables. When adding merge children, the merge
engine would extend the table list. Then, when adding
prelocked tables, the prelocking algorithm would use a pointer
to the last merge child to assign to lex->query_tables_own_last.
Then, when merge children were removed at the end of
open_tables(), lex->query_tables_own_last
was not updated, and kept pointing
to a removed merge child.
The fix ensures that query_tables_own_last is always in
sync with lex->query_tables_last.
This is a regression introduced by WL#4144 and present only
in next-4284 tree and 6.0.
TEMPORARY + HANDLER + LOCK + SP".
Server crashed when one:
1) Opened HANDLER or acquired global read lock
2) Then locked one or several temporary tables with
LOCK TABLES statement (but no base tables).
3) Then issued any statement causing commit (explicit
or implicit).
4) Issued statement which should have closed HANDLER
or released global read lock.
The problem was that when entering LOCK TABLES mode in the
scenario described above we incorrectly set transactional
MDL sentinel to zero. As result during commit all metadata
locks were released (including lock for open HANDLER or
global metadata shared lock). Indeed, attempt to release
metadata lock for the second time which happened during
HANLDER CLOSE or during release of GLR caused crash.
This patch fixes problem by changing MDL_context's
set_trans_sentinel() method to set sentinel to correct
value (it should point to the most recent ticket).
DDL workload".
When a RENAME TABLE or LOCK TABLE ... WRITE statement which
mentioned the same table several times were aborted during
the process of acquring metadata locks (due to deadlock
which was discovered or because of KILL statement) server
might have crashed.
When attempt to acquire all locks requested had failed we
went through the list of requests and released locks which
we have managed to acquire by that moment one by one. Since
in the scenario described above list of requests contained
duplicates this led to releasing the same ticket twice and
a crash as result.
This patch solves the problem by employing different approach
to releasing locks in case of failure to acquire all locks
requested.
Now we take a MDL savepoint before starting acquiring locks
and simply rollback to it if things go bad.
This bug is just one facet of stored routines not being able to
detect changes in meta-data (WL#4179). This particular problem
can be triggered within a single session due to the improper
management of the pre-locking list if the view is expanded after
the pre-locking list is calculated.
Since the overall solution for the meta-data detection issue is
planned for a later release, for now a workaround is used to
fix this particular aspect that only involves a single session.
The workaround is to flush the thread-local stored routine cache
every time a view is created or modified, causing locally cached
routines to be re-evaluated upon invocation.
