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.
sql/rpl_rli.h:
Made inited Volatile (find inline comments)
sql/slave.cc:
backported all changes from the fix of BUG#11752963.
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.)
mysql-test/valgrind.supp:
Add new Memcheck suppressions for filesort.
sql/filesort.cc:
Remove the ifdef HAVE_purify/bzero code, use valgrind suppressions instead.
Blind attempt to fix BUG 12881278 - MAIN.MYISAM TEST FAILS ON LINUX
The printed text is truncated on char 63:
"MySQL thread id 1236, OS thread handle 0x7ff187b96700, query id"
still I do not understand how this truncation could have caused the
main.myisam failure but anyway - the buffer needs to be increased.
Added a second internal variable $mysql_errname
This is set the same way as $mysql_errno
Can be used like "if ($mysql_errname == ER_NO_SUCH_TABLE)...."
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.
mysql-test/r/merge.result:
A test case for BUG#11763712.
mysql-test/t/merge.test:
A test case for BUG#11763712.
sql/sql_base.cc:
When flushing tables under LOCK TABLES, all locked
and flushed tables are released and then reopened.
It may happen that we failed to reopen some tables,
in this case we reopen as much tables as possible.
If it was not possible to reopen MERGE child, MERGE
parent is unusable and must be removed from thread
open tables list.
If it was not possible to reopen MERGE parent, all
MERGE child table objects are unusable as well, at
least because their locks are handled by MERGE parent.
They must also be removed from thread open tables
list.
In other words if it was impossible to reopen any
object of a MERGE table or reattach child tables,
all objects of this MERGE table must be considered
unusable and closed.
Also addressed issues in bug #11745133, where we could mark a table
corrupted instead of crashing the server when found a corrupted buffer/page
if the table created with innodb_file_per_table on.
Undo previous fix, it is not reliable
Drop setting $MYSQL_LIBDIR, mtr can't be sure anyway
Test is set to override plugin-dir to some known existing dir
to mysql-5.5.16-release.
Original revision:
# revision-id: dmitry.lenev@oracle.com-20110811155849-feyt3h7tj48padiu
# parent: tatjana.nuernberg@oracle.com-20110811120945-c6x9a5d2du8s9oj2
# committer: Dmitry Lenev <Dmitry.Lenev@oracle.com>
# branch nick: mysql-5.5-12828477
# timestamp: Thu 2011-08-11 19:58:49 +0400
# message:
# Fix for bug #12828477 - "MDL SUBSYSTEM CREATES BIG OVERHEAD
# FOR CERTAIN QUERIES TO INFORMATION_SCHEMA".
#
# The problem was that metadata locking subsystem introduced
# too much overhead for queries to I_S which were processed by
# opening only .FRM or .TRG files and had to scanned a lot of
# tables (e.g. SELECT COUNT(*) FROM I_S.TRIGGERS was affected).
# The same effect was not observed for similar queries which
# performed full-blown table open in order to fill I_S table.
#
# The problem stemmed from the fact that in case when I_S
# implementation opened only .FRM or .TRG file for each table
# processed it didn't release metadata lock it has acquired on
# the table after finishing its processing. As result, list
# of acquired metadata locks were growing until the end of
# statement. Since acquisition of each new lock required
# search in the list of already acquired locks performance
# degraded.
#
# The same effect is not observed when I_S implementation
# performs full-blown table open for each table being
# processed, as in the latter cases metadata lock on the
# table is released right after table processing.
#
# This fix addressed the problem by ensuring that I_S
# implementation releases metadata lock after processing
# the table in both cases of full-blown table open and in
# case when only .FRM or .TRG file is read.
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
