Taking care of it.  

      
There are two threads.  In one thread, dml operation is going on 
involving cascaded update operation.  In another thread, alter 
table add foreign key constraint is happening.  Under these 
circumstances, it is possible for the dml thread to access a 
dict_foreign_t object that has been freed by the ddl thread.  
The debug sync test case provides the sequence of operations.  
Without fix, the test case will crash the server (because of 
newly added assert).  With fix, the alter table stmt will return 
an error message.  
      
Backporting the fix from MySQL 5.5 to 5.1

rb:961
rb:947

Backport of fix for:
Bug#53236 Segfault in DTCollation::set(DTCollation&)

On shutdown(), Windows can drop traffic still queued for sending even if that
wasn't specifically requested. As a result, fatal errors (those after
signaling which the server will drop the connection) were sometimes only
seen as "connection lost" on the client side, because the server-side
shutdown() erraneously discarded the correct error message before sending
it.

If on Windows, we now use the Windows API to access the (non-broken) equivalent
of shutdown().

Backport from trunk

On shutdown(), Windows can drop traffic still queued for sending even if that
wasn't specifically requested. As a result, fatal errors (those after
signaling which the server will drop the connection) were sometimes only
seen as "connection lost" on the client side, because the server-side
shutdown() erraneously discarded the correct error message before sending
it.

If on Windows, we now use the Windows API to access the (non-broken) equivalent
of shutdown().

Backport from trunk

include/violite.h:
  export mysql_socket_shutdown(). It lives in vio in the backport.
sql/mysqld.cc:
  Go through our own shutdown() rather than straight to the POSIX one.
vio/viosocket.c:
  Define mysql_socket_shutdown(). On UNIXoid systems, it's just a wrapper for shutdown(), but
  on Window, it uses DisconnectEx, which is magic.

This bug was originally filed and fixed as Bug#12612184. The original
fix was buggy, and it was patched by Bug#12704861. Also that patch was
buggy (potentially breaking crash recovery), and both fixes were
reverted.

This fix was not ported to the built-in InnoDB of MySQL 5.1, because
the function signatures of many core functions are different from
InnoDB Plugin and later versions. The block allocation routines and
their callers would have to changed so that they handle block
descriptors instead of page frames.

When a record is updated so that its size grows, non-updated columns
can be selected for external (off-page) storage. The bug is that the
initially inserted updated record contains an all-zero BLOB pointer to
the field that was not updated. Only after the BLOB pages have been
allocated and written, the valid pointer can be written to the record.

Between the release of the page latch in mtr_commit(mtr) after
btr_cur_pessimistic_update() and the re-latching of the page in
btr_pcur_restore_position(), other threads can see the invalid BLOB
pointer consisting of 20 zero bytes. Moreover, if the system crashes
at this point, the situation could persist after crash recovery, and
the contents of the non-updated column would be permanently lost.

The problem is amplified by the ROW_FORMAT=DYNAMIC and
ROW_FORMAT=COMPRESSED that were introduced in
innodb_file_format=barracuda in InnoDB Plugin, but the bug does exist
in all InnoDB versions.

The fix is as follows. After a pessimistic B-tree operation that needs
to write out off-page columns, allocate the pages for these columns in
the mini-transaction that performed the B-tree operation (btr_mtr),
but write the pages in a separate mini-transaction (blob_mtr). Do
mtr_commit(blob_mtr) before mtr_commit(btr_mtr). A quirk: Do not reuse
pages that were previously freed in btr_mtr. Only write the off-page
columns to 'fresh' pages.

In this way, crash recovery will see redo log entries for blob_mtr
before any redo log entry for btr_mtr. It will apply the BLOB page
writes to pages that were marked free at that point. If crash recovery
fails to see all of the btr_mtr redo log, there will be some
unreachable BLOB data in free pages, but the B-tree will be in a
consistent state.

btr_page_alloc_low(): Renamed from btr_page_alloc(). Add the parameter
init_mtr. Return an allocated block, or NULL. If init_mtr!=mtr but
the page was already X-latched in mtr, do not initialize the page.

btr_page_alloc(): Wrapper for btr_page_alloc_for_ibuf() and
btr_page_alloc_low().

btr_page_free(): Add a debug assertion that the page was a B-tree page.

btr_lift_page_up(): Return the father block.

btr_compress(), btr_cur_compress_if_useful(): Add the parameter ibool
adjust, for adjusting the cursor position.

btr_cur_pessimistic_update(): Preserve the cursor position when
big_rec will be written and the new flag BTR_KEEP_POS_FLAG is defined.
Remove a duplicate rec_get_offsets() call. Keep the X-latch on
index->lock when big_rec is needed.

btr_store_big_rec_extern_fields(): Replace update_inplace with
an operation code, and local_mtr with btr_mtr. When not doing a
fresh insert and btr_mtr has freed pages, put aside any pages that
were previously X-latched in btr_mtr, and free the pages after
writing out all data. The data must be written to 'fresh' pages,
because btr_mtr will be committed and written to the redo log after
the BLOB writes have been written to the redo log.

btr_blob_op_is_update(): Check if an operation passed to
btr_store_big_rec_extern_fields() is an update or insert-by-update.

fseg_alloc_free_page_low(), fsp_alloc_free_page(),
fseg_alloc_free_extent(), fseg_alloc_free_page_general(): Add the
parameter init_mtr. Return an allocated block, or NULL. If
init_mtr!=mtr but the page was already X-latched in mtr, do not
initialize the page.

xdes_get_descriptor_with_space_hdr(): Assert that the file space
header is being X-latched.

fsp_alloc_from_free_frag(): Refactored from fsp_alloc_free_page().

fsp_page_create(): New function, for allocating, X-latching and
potentially initializing a page. If init_mtr!=mtr but the page was
already X-latched in mtr, do not initialize the page.

fsp_free_page(): Add ut_ad(0) to the error outcomes.

fsp_free_page(), fseg_free_page_low(): Increment mtr->n_freed_pages.

fsp_alloc_seg_inode_page(), fseg_create_general(): Assert that the
page was not previously X-latched in the mini-transaction. A file
segment or inode page should never be allocated in the middle of an
mini-transaction that frees pages, such as btr_cur_pessimistic_delete().

fseg_alloc_free_page_low(): If the hinted page was allocated, skip the
check if the tablespace should be extended. Return NULL instead of
FIL_NULL on failure. Remove the flag frag_page_allocated. Instead,
return directly, because the page would already have been initialized.

fseg_find_free_frag_page_slot() would return ULINT_UNDEFINED on error,
not FIL_NULL. Correct a bogus assertion.

fseg_alloc_free_page(): Redefine as a wrapper macro around
fseg_alloc_free_page_general().

buf_block_buf_fix_inc(): Move the definition from the buf0buf.ic to
buf0buf.h, so that it can be called from other modules.

mtr_t: Add n_freed_pages (number of pages that have been freed).

page_rec_get_nth_const(), page_rec_get_nth(): The inverse function of
page_rec_get_n_recs_before(), get the nth record of the record
list. This is faster than iterating the linked list. Refactored from
page_get_middle_rec().

trx_undo_rec_copy(): Add a debug assertion for the length.

trx_undo_add_page(): Return a block descriptor or NULL instead of a
page number or FIL_NULL.

trx_undo_report_row_operation(): Add debug assertions.

trx_sys_create_doublewrite_buf(): Assert that each page was not
previously X-latched.

page_cur_insert_rec_zip_reorg(): Make use of page_rec_get_nth().

row_ins_clust_index_entry_by_modify(): Pass BTR_KEEP_POS_FLAG, so that
the repositioning of the cursor can be avoided.

row_ins_index_entry_low(): Add DEBUG_SYNC points before and after
writing off-page columns. If inserting by updating a delete-marked
record, do not reposition the cursor or commit the mini-transaction
before writing the off-page columns.

row_build(): Tighten a debug assertion about null BLOB pointers.

row_upd_clust_rec(): Add DEBUG_SYNC points before and after writing
off-page columns. Do not reposition the cursor or commit the
mini-transaction before writing the off-page columns.

rb:939 approved by Jimmy Yang

error LNK2001: unresolved external symbol _debug_sync_C_callback_ptr

OF WIDE RECORDS

row_ins_index_entry_low(), row_upd_clust_rec(): Make a redo log
checkpoint if a DEBUG flag is set. Add DEBUG_SYNC around
btr_store_big_rec_extern_fields().

rb:946 approved by Jimmy Yang

Before killing the server, tell mysql-test-run that it is to be expected.

Discussed with Bjorn Munch on IM.

$SUBJ$
1. Took a diff between the previous base version and the
mysql sources.
2. Added the new 2.1.4 base version.
3. Reviewed and re-applied the diff from step #1.

AND 5.5 YASSL FIXES.

Took the 5.5 yassl directory and moved it to the 5.1 tree, while
preserving the makefiles.

AND 5.5 YASSL FIXES.

Took the 5.5 yassl code and applied it to the 5.0 codebase, keeping the
compilation files.

            
During FIC error handling the trx->error_state was not being set to DB_SUCCESS
after failure, before attempting the next DDL SQL operation. This reset to
DB_SUCCESS is somewhat of a requirement though not explicitly stated anywhere.
The fix is to reset it to DB_SUCCESS in row0merge.cc if row_merge_rename_indexes
or row_merge_drop_index functions fail, also reset to DB_SUCCESS at trx commit.
				          
rb://935 Approved by Jimmy Yang.

IS EXECUTED TWICE FROM P

This bug is a duplicate of bug 12567331, which was pushed to the
optimizer backporting tree on 2011-06-11. This is just a back-port of
the fix. Both test cases are included as they differ somewhat.

GRACEFUL SHUTDOWN

During startup mysql picks up .frm files from the tmpdir directory and
tries to drop those tables in the storage engine.

The problem is that when tmpdir ends in / then ha_innobase::delete_table()
is passed a string like "/var/tmp//#sql123", then it wrongly normalizes it
to "/#sql123" and calls row_drop_table_for_mysql() which of course fails
to delete the table entry from the InnoDB dictionary cache.
ha_innobase::delete_table() returns an error but nevertheless mysql wipes
away the .frm file and the entry in the InnoDB dictionary cache remains
orphaned with no easy way to remove it.

The "no easy" way to remove it is to create a similar temporary table again,
copy its .frm file to tmpdir under "#sql123.frm" and restart mysqld with
tmpdir=/var/tmp (no trailing slash) - this way mysql will pick the .frm file
after restart and will try to issue drop table for "/var/tmp/#sql123"
(notice do double slash), ha_innobase::delete_table() will normalize it to
"tmp/#sql123" and row_drop_table_for_mysql() will successfully remove the
table entry from the dictionary cache.

The solution is to fix normalize_table_name_low() to normalize things like
"/var/tmp//table" correctly to "tmp/table".

This patch also adds a test function which invokes
normalize_table_name_low() with various inputs to make sure it works
correctly and a mtr test that calls this test function.

Reviewed by:	Marko (http://bur03.no.oracle.com/rb/r/929/)

                      CORRUPTED WHEN RUN CONCURRENTLY WITH

ISSUE: Table corruption due to concurrent queries.
       Different threads running check, repair query
       along with insert. Locks not properly acquired
       in repair query. Rows are inserted inbetween
       repair query.

SOLUTION: Mutex lock is acquired before the
          repair call. Concurrent queries wont
          effect the call to repair.

Recording correct test results.

modified:
  mysql-test/suite/engines/funcs/r/db_alter_collate_ascii.result
  mysql-test/suite/engines/funcs/r/db_alter_collate_utf8.result

row_merge_buf_write(): Relax the bogus assertion.