when buffered changes are to be discarded

sync_thread_add_level(level = SYNC_IBUF_INDEX_TREE): Relax a too strict
condition that the thread must not be holding locks below SYNC_FSP_PAGE.
It is perfectly valid to hold any latch above SYNC_IBUF_INDEX_TREE when
acquiring the insert buffer tree latch.

bugs in it - accessing uninitialized ::len member (thanks, Jimmy!)
and a memory leak.

This is a followup to vasil.dimov@oracle.com-20110909070724-jvirxnpkbxieauz5
which disabled the prefetch code.

when buffered changes are to be discarded

ibuf_add_free_page(): Lower the latching order of the newly allocated page
to SYNC_IBUF_TREE_NODE_NEW after latching the insert buffer tree root.

This bug always was bogus UNIV_SYNC_DEBUG alarm. The function
buf_block_dbg_add_level() is a no-op unless UNIV_SYNC_DEBUG is defined.

When there is a secondary index on a column prefix of an externally
stored column and an entry in the secondary index is shorter than the
reserved prefix length, it should mean that the secondary index entry
is holding the complete column value. When comparing this secondary
index column value to the column in the clustered index row, we must
compare the entire prefix that was fetched from the clustered
index. The bug was that we would just compare that the column in the
clustered index starts with the value found in the secondary index
column.

This bug affects only the InnoDB Barracuda formats (ROW_FORMAT=DYNAMIC
and ROW_FORMAT=COMPRESSED), in which columns that are stored off-page
in the clustered index do not contain any prefix in the clustered
index record.

row_sel_sec_rec_is_for_blob(): Add the parameter prefix_len, for
ifield->prefix_len. Add some assertions.

Sorry, I did not manage to produce a test case. This patch does
produce correct results on the data set that Michael isolated on our
test machine. That was with the purge and background rollback
suspended, because they would make the bug go away.

rb:760 approved by Sunny Bains

This change is a followup to
vasil.dimov@oracle.com-20110907145810-v98kldmho23vhhic
which triggered the usage of the prefetch and valgrind tests spat lots of
warnings.

The prefetch code will be removed.

Discussed with:	Marko (over IM)

InnoDB acquires an x-latch on btr_search_latch for certain in-place updates
that do affect the adaptive hash index. These operations do not really need
to be protected by the btr_search_latch:

* updating DB_TRX_ID
* updating DB_ROLL_PTR
* updating PAGE_MAX_TRX_ID
* updating the delete-mark flag

rb:750 approved by Sunny Bains

Tweak the faulty UNIV_SYNC_DEBUG diagnostics a little bit more.

ibuf_add_free_page(): Lower the latching order of the newly allocated page
only after acquiring the ibuf_mutex.

DROP_TABLE_PROC().

With this change I observe a speedup from 6.2s to 0.1s when executing
DROP_TABLE_PROC() during DROP TABLE with 512 foreign keys, like what
is being done in innodb_bug56143.test

This fixes "Bug#11765460 DROP TABLE USES INEFFICIENT METHODS TO REMOVE
FKS/INDEXES FROM INNODB SYS TABLES"

Reviewed by:	Marko

                            (EG: --DEFAULTS-FILE )
  
Updating help message in scripts/mysql_install_db.pl.in file.

                    (EG: --DEFAULTS-FILE )

Added help message for the missing options (--no-defaults,
--defaults-file and --defaults-extra-file).

buf_buddy_relocate(): The ut_time_us() function is needed for
statistics, calculating the total time spent on relocating blocks.
Until now, we invoked ut_time_us() every time buf_buddy_relocate() was
called. Fix: Only call ut_time_us() when the block can be relocated.
After this fix, the reported relocated_usec will no longer include the
time for the page_hash lookup and for acquiring the block mutex.

Approved by Sunny Bains on IM

The original fix was accidentally pushed to mysql-5.1 after the 5.1.59
clone-off in bzr revision id
marko.makela@oracle.com-20110829081642-z0w992a0mrc62s6w with thne fix
of Bug#12704861 Corruption after a crash during BLOB update.
It was pushed separately to mysql-5.5 in bzr revision id
marko.makela@oracle.com-20110901184804-2901f6qmuro3jas8.

trx_undo_report_row_operation(): If the page for which the undo log
was too big was empty, commit and start the mini-transaction before
acquiring the rollback segment mutex and freeing the undo page. This
is necessary, because the mini-transaction may be holding lower-order
latches in the levels SYNC_FSP and SYNC_FSP_PAGE.

trx_undo_erase_page_end(): Erase also empty pages, because
trx_undo_report_row_operation() needs to commit the mini-transaction
before freeing the empty page.

rb:756 approved by Sunny Bains

Post-push fix:
The functions write_keys() and find_all_keys() may have a slightly
different function signature, depending on compiler/platform/flags.

GROUPING BY FUNCTIONS.... (PART

The bug was introduced in a patch for bug 49897.

Problem: The assertion inserted by the original patch to guard against
zero-lenght sort keys during merge phase triggers also when the whole
set fits in memory.

Fix: Move assert so that it does not trigger if the whole set is in
memory.

Converting the number zero to binary and back yielded the number zero,
but with no digits, i.e. zero precision.
This made the multiply algorithm go haywire in various ways.

The fix of Bug#12612184 broke crash recovery. When a record that
contains off-page columns (BLOBs) is updated, we must first write redo
log about the BLOB page writes, and only after that write the redo log
about the B-tree changes. The buggy fix would log the B-tree changes
first, meaning that after recovery, we could end up having a record
that contains a null BLOB pointer.

Because we will be redo logging the writes off the off-page columns
before the B-tree changes, we must make sure that the pages chosen for
the off-page columns are free both before and after the B-tree
changes. In this way, the worst thing that can happen in crash
recovery is that the BLOBs are written to free pages, but the B-tree
changes are not applied. The BLOB pages would correctly remain free in
this case. To achieve this, we must allocate the BLOB pages in the
mini-transaction of the B-tree operation. A further quirk is that BLOB
pages are allocated from the same file segment as leaf pages. Because
of this, we must temporarily "hide" any leaf pages that were freed
during the B-tree operation by "fake allocating" them prior to writing
the BLOBs, and freeing them again before the mtr_commit() of the
B-tree operation, in btr_mark_freed_leaves().

btr_cur_mtr_commit_and_start(): Remove this faulty function that was
introduced in the Bug#12612184 fix. The problem that this function was
trying to address was that when we did mtr_commit() the BLOB writes
before the mtr_commit() of the update, the new BLOB pages could have
overwritten clustered index B-tree leaf pages that were freed during
the update. If recovery applied the redo log of the BLOB writes but
did not see the log of the record update, the index tree would be
corrupted. The correct solution is to make the freed clustered index
pages unavailable to the BLOB allocation. This function is also a
likely culprit of InnoDB hangs that were observed when testing the
Bug#12612184 fix.

btr_mark_freed_leaves(): Mark all freed clustered index leaf pages of
a mini-transaction allocated (nonfree=TRUE) before storing the BLOBs,
or freed (nonfree=FALSE) before committing the mini-transaction.

btr_freed_leaves_validate(): A debug function for checking that all
clustered index leaf pages that have been marked free in the
mini-transaction are consistent (have not been zeroed out).

btr_page_alloc_low(): Refactored from btr_page_alloc(). Return the
number of the allocated page, or FIL_NULL if out of space. Add the
parameter "mtr_t* init_mtr" for specifying the mini-transaction where
the page should be initialized, or if this is a "fake allocation"
(init_mtr=NULL) by btr_mark_freed_leaves(nonfree=TRUE).

btr_page_alloc(): Add the parameter init_mtr, allowing the page to be
initialized and X-latched in a different mini-transaction than the one
that is used for the allocation. Invoke btr_page_alloc_low(). If a
clustered index leaf page was previously freed in mtr, remove it from
the memo of previously freed pages.

btr_page_free(): Assert that the page is a B-tree page and it has been
X-latched by the mini-transaction. If the freed page was a leaf page
of a clustered index, link it by a MTR_MEMO_FREE_CLUST_LEAF marker to
the mini-transaction.

btr_store_big_rec_extern_fields_func(): Add the parameter alloc_mtr,
which is NULL (old behaviour in inserts) and the same as local_mtr in
updates. If alloc_mtr!=NULL, the BLOB pages will be allocated from it
instead of the mini-transaction that is used for writing the BLOBs.

fsp_alloc_from_free_frag(): Refactored from
fsp_alloc_free_page(). Allocate the specified page from a partially
free extent.

fseg_alloc_free_page_low(), fseg_alloc_free_page_general(): Add the
parameter "mtr_t* init_mtr" for specifying the mini-transaction where
the page should be initialized, or NULL if this is a "fake allocation"
that prevents the reuse of a previously freed B-tree page for BLOB
storage. If init_mtr==NULL, try harder to reallocate the specified page
and assert that it succeeded.

fsp_alloc_free_page(): Add the parameter "mtr_t* init_mtr" for
specifying the mini-transaction where the page should be initialized.
Do not allow init_mtr == NULL, because this function is never to be
used for "fake allocations".

mtr_t: Add the operation MTR_MEMO_FREE_CLUST_LEAF and the flag
mtr->freed_clust_leaf for quickly determining if any
MTR_MEMO_FREE_CLUST_LEAF operations have been posted.

row_ins_index_entry_low(): When columns are being made off-page in
insert-by-update, invoke btr_mark_freed_leaves(nonfree=TRUE) and pass
the mini-transaction as the alloc_mtr to
btr_store_big_rec_extern_fields(). Finally, invoke
btr_mark_freed_leaves(nonfree=FALSE) to avoid leaking pages.

row_build(): Correct a comment, and add a debug assertion that a
record that contains NULL BLOB pointers must be a fresh insert.

row_upd_clust_rec(): When columns are being moved off-page, invoke
btr_mark_freed_leaves(nonfree=TRUE) and pass the mini-transaction as
the alloc_mtr to btr_store_big_rec_extern_fields(). Finally, invoke
btr_mark_freed_leaves(nonfree=FALSE) to avoid leaking pages.

buf_reset_check_index_page_at_flush(): Remove. The function
fsp_init_file_page_low() already sets
bpage->check_index_page_at_flush=FALSE.

There is a known issue in tablespace extension. If the request to
allocate a BLOB page leads to the tablespace being extended, crash
recovery could see BLOB writes to pages that are off the tablespace
file bounds. This should trigger an assertion failure in fil_io() at
crash recovery. The safe thing would be to write redo log about the
tablespace extension to the mini-transaction of the BLOB write, not to
the mini-transaction of the record update. However, there is no redo
log record for file extension in the current redo log format.

rb:693 approved by Sunny Bains

Background: Backporting fix for BUG 11752963 to Mysql5.1 branch.
Problem: Fix of bug 11752963 was only available for trunk and 5.5 branch.
Partial fix has been pushed to 5.1 branch as well. 
Fix: backporting the fixes of bug 11752963 to 5.1 branch. 
1. Made all major changes to make 5.1 branch in line with 5.5 and the trunk.
2. skipped the partial patch that was already applied to the 5.1 branch. 

Suppress the known warnings generated by filesort().

The real fix belongs to worklog 1509:
Pack values of non-sorted fields in the sort buffer
(which is basically the same issue, but in an optimization context:
 We are writing the entire sort buffer to disk, 
 including un-used space for varchar columns.)

The fix in revision id marko.makela@oracle.com-20110815091143-h3zbvm0pv8ni3qql
introduced a false UNIV_SYNC_DEBUG alarm. Relax the assertion.

On Fedora, certain accesses to "/var/lib/mysql/HOSTNAME.err" were blocked
by SELinux policy, this made the server start fail with the message
    Manager of pid-file quit without updating file
Calling "/sbin/restorecon -R /var/lib/mysql" fixes this.

                      CRASHES SERVER

Flushing of MERGE table or one of its child tables, which was
locked by flushing thread using LOCK TABLES, might have caused
crashes or assertion failures if the thread failed to reopen
child or parent table.
Particularly, this might have happened when another connection
killed this FLUSH TABLE statement/connection.
Also this problem might have occurred when we failed to reopen
MERGE table or one of its children when executing DDL statement
under LOCK TABLES.

The problem was caused by the fact that reopen_tables() might
have failed to reopen child table but still tried to reopen,
reattach children for and re-lock its parent. Vice versa it
might have failed to reopen parent but kept references from
children to parent around. Since reopen_tables() closes table
it has failed to reopen and therefore frees all associated
memory such dangling references led to crashes when followed.

This patch solves this problem by ensuring that we always close
parent table and all its children if we fail to reopen this
table or one of its children. Same happens if we fail to reattach
children to parent.

Affects 5.1 only.

Just put it back in where it was.

discarded in buf_page_create()

This bug turned out to be a false alarm, a bug in the UNIV_SYNC_DEBUG
diagnostic code. Because of this, the patch was not backported to the
built-in InnoDB in MySQL 5.1. Furthermore, there is no test case for
InnoDB Plugin in MySQL 5.1, because the delete buffering in MySQL 5.5
makes triggering the failure much easier.

When a freed page for which there exist orphaned buffered changes is
allocated and reused for something else, buf_page_create() will discard
the buffered changes by invoking ibuf_merge_or_delete_for_page().
This would violate the InnoDB latching order.

Tweak the latching order as follows. Move SYNC_IBUF_MUTEX below
SYNC_FSP_PAGE, where it logically belongs, and assign new latching
levels for the ibuf->index->lock and the insert buffer B-tree pages:

#define SYNC_IBUF_MUTEX		370	/* ibuf_mutex */
#define SYNC_IBUF_INDEX_TREE	360
#define SYNC_IBUF_TREE_NODE_NEW	359
#define SYNC_IBUF_TREE_NODE	358

btr_block_get(), btr_page_get(): In UNIV_SYNC_DEBUG, add the parameter
"index" for determining the appropriate latching order
(SYNC_IBUF_TREE_NODE or SYNC_TREE_NODE).

btr_page_alloc_for_ibuf(), btr_create(): Use SYNC_IBUF_TREE_NODE_NEW
instead of SYNC_TREE_NODE_NEW for insert buffer pages.

btr_cur_search_to_nth_level(), btr_pcur_restore_position_func(): Use
SYNC_IBUF_TREE_NODE instead of SYNC_TREE_NODE for insert buffer pages.

btr_search_guess_on_hash(): Assert that the index is not an insert buffer tree.

dict_index_add_to_cache(): Use SYNC_IBUF_INDEX_TREE for the insert
buffer tree (ibuf->index->lock).

ibuf0ibuf.c: Use SYNC_IBUF_TREE_NODE or SYNC_IBUF_TREE_NODE_NEW for
all B-tree pages.

ibuf_merge_or_delete_for_page(): Assert that the user page is
BUF_IO_READ fixed. Only in this way it is OK to latch it as
SYNC_IBUF_TREE_NODE instead of the proper SYNC_TREE_NODE (which would
violate the changed latching order).

sync_thread_add_level(): Remove the special tweak for
SYNC_IBUF_MUTEX. Add rules for the added latching levels.

rb:591 approved by Jimmy Yang

row_sel_field_store_in_mysql_format(): Do not pad the unused part of
the buffer reserved for a True VARCHAR column (introduced in 5.0.3).
Add Valgrind instrumentation ensuring that the unused part will be
flagged uninitialized.

row_sel_copy_cached_field_for_mysql(): New function: Copy a field
that is in the MySQL row format, not copying the unused tail of
VARCHAR columns.

row_sel_pop_cached_row_for_mysql(): Invoke
row_sel_copy_cached_field_for_mysql() for copying fields.
When the row is long, copy it field-by-field.

rb:715 approved by Inaam Rana