This fix is for 5.1 only : back porting the 6.0 patch manually
The parser code in sql/sql_yacc.yy needs to be more robust to out of
memory conditions, so that when parsing a query fails due to OOM,
the thread gracefully returns an error.
Before this fix, a new/alloc returning NULL could:
- cause a crash, if dereferencing the NULL pointer,
- produce a corrupted parsed tree, containing NULL nodes,
- alter the semantic of a query, by silently dropping token values or nodes
With this fix:
- C++ constructors are *not* executed with a NULL "this" pointer
when operator new fails.
This is achieved by declaring "operator new" with a "throw ()" clause,
so that a failed new gracefully returns NULL on OOM conditions.
- calls to new/alloc are tested for a NULL result,
- The thread diagnostic area is set to an error status when OOM occurs.
This ensures that a request failing in the server properly returns an
ER_OUT_OF_RESOURCES error to the client.
- OOM conditions cause the parser to stop immediately (MYSQL_YYABORT).
This prevents causing further crashes when using a partially built parsed
tree in further rules in the parser.
No test scripts are provided, since automating OOM failures is not
instrumented in the server.
Tested under the debugger, to verify that an error in alloc_root cause the
thread to returns gracefully all the way to the client application, with
an ER_OUT_OF_RESOURCES error.
Post-merge fix: mysql_client_test.c is compiled by C compilers
and some C compilers don't support mixed declarations and code
and it's explicitly forbidden by ISO C90.
partition is corrupt
The main problem was that ALTER TABLE t ANALYZE/CHECK/OPTIMIZE/REPAIR
PARTITION took another code path (over mysql_alter_table instead of
mysql_admin_table) which differs in two ways:
1) alter table opens the tables in a different way than admin tables do
resulting in returning with error before it tried the command
2) alter table does not start to send any diagnostic rows to the client
which the lower admin functions continue to use -> resulting in
assertion crash
The fix:
Remapped ALTER TABLE t ANALYZE/CHECK/OPTIMIZE/REPAIR PARTITION to use
the same code path as ANALYZE/CHECK/OPTIMIZE/REPAIR TABLE t.
Adding check in mysql_admin_table to setup the partition list for
which partitions that should be used.
Partitioned tables will still not work with
REPAIR TABLE/PARTITION USE_FRM, since that requires moving partitions
to tables, REPAIR TABLE t USE_FRM, and check that the data still
fulfills the partitioning function and then move the table back to
being a partition.
NOTE: I have removed the following functions from the handler
interface:
analyze_partitions, check_partitions, optimize_partitions,
repair_partitions
Since they are not longer needed.
THIS ALTERS THE STORAGE ENGINE API
This fix is for 5.0 only : back porting the 6.0 patch manually
The parser code in sql/sql_yacc.yy needs to be more robust to out of
memory conditions, so that when parsing a query fails due to OOM,
the thread gracefully returns an error.
Before this fix, a new/alloc returning NULL could:
- cause a crash, if dereferencing the NULL pointer,
- produce a corrupted parsed tree, containing NULL nodes,
- alter the semantic of a query, by silently dropping token values or nodes
With this fix:
- C++ constructors are *not* executed with a NULL "this" pointer
when operator new fails.
This is achieved by declaring "operator new" with a "throw ()" clause,
so that a failed new gracefully returns NULL on OOM conditions.
- calls to new/alloc are tested for a NULL result,
- The thread diagnostic area is set to an error status when OOM occurs.
This ensures that a request failing in the server properly returns an
ER_OUT_OF_RESOURCES error to the client.
- OOM conditions cause the parser to stop immediately (MYSQL_YYABORT).
This prevents causing further crashes when using a partially built parsed
tree in further rules in the parser.
No test scripts are provided, since automating OOM failures is not
instrumented in the server.
Tested under the debugger, to verify that an error in alloc_root cause the
thread to returns gracefully all the way to the client application, with
an ER_OUT_OF_RESOURCES error.
running on Windows
We used two OS-specific methods of looking up the executable
name, which don't work outside of those two kinds of OSes
(Linux+Solaris and Windows).
We assume that if the user ran this program with a certain
name, we can run the other sibling programs with a similar name.
(re-patch in bzr)
Post-merge fix: Alter linking order so that the thread linking
flags appear last in the list. This needs to be done this way
because some linkers will not search the thread archive again
if a undefined symbol (pthread_kill in this case) appears later.
min() and max() functions are implemented in MySQL as macros.
This means that max(a,b) is expanded to: ((a) > (b) ? (a) : (b))
Note how 'a' is quoted two times.
Now imagine 'a' is a recursive function call that's several 10s of levels deep.
And the recursive function does max() with a function arg as well to dive into
recursion.
This means that simple function call can take most of the clock time.
Identified and fixed several such calls to max()/min() : including the IF()
sql function implementation.
Calling List<Cached_item>::delete_elements for the same list twice
caused a crash of the server in the function JOIN::cleaunup.
Ensured that delete_elements() in JOIN::cleanup would be called only once.
