Refactor the !rec_offs_any_extern relaxation in row_build().

trx_assert_active(trx_id): Assert that the given transaction is active.
(In the 5.1 built-in InnoDB, there is no trx->is_recovered field.)

trx_assert_recovered(trx_id): Assert that the given transaction is
active and has been recovered after a crash.

row_build(): Replace a bunch of code with an assertion that invokes
trx_assert_active() or trx_assert_recovered() and row_get_rec_trx_id().

row_get_trx_id_offset(): Make the function inlined. Remove the unused
parameter rec, and make all parameters const.

row_get_rec_trx_id(), row_get_rec_roll_ptr(): Make all parameters const.

rb:691 approved by Jimmy Yang

page_zip_dir_elems(): New function, refactored from page_zip_dir_size().

page_zip_dir_size(): Use page_zip_dir_elems()

page_zip_dir_start_offs(): New function: Gets an offset to the
compressed page trailer (the dense page directory), including deleted
records (the free list)

page_zip_dir_start_low(page_zip, n_dense): Constness-preserving
wrapper macro for page_zip_dir_start_offs().

page_zip_dir_start(page_zip): Constness-preserving
wrapper macro for page_zip_dir_start_offs().

page_zip_decompress_node_ptrs(), page_zip_decompress_clust(): Replace
a formula with a fully equivalent page_zip_dir_start_low() call.

page_zip_write_rec(), page_zip_parse_write_node_ptr(),
page_zip_write_node_ptr(), page_zip_write_trx_id_and_roll_ptr(),
page_zip_clear_rec(): Replace a formula with an almost equivalent
page_zip_dir_start() call.
It is OK to replace page_dir_get_n_heap(page) with
page_dir_get_n_heap(page_zip->data), because
ut_ad(page_zip_header_cmp(page_zip, page)) or
page_zip_validate(page_zip, page) asserts that the
page headers are identical.

rb:687 approved by Jimmy Yang

BOGUS "THE TABLE MYSQL.PROC IS MISSING,..."

There was a race condition between loading a stored routine
(function/procedure/trigger) specified by fully qualified name
SCHEMA_NAME.PROC_NAME and dropping the stored routine database.

The problem was that there is a window for race condition when one server
thread tries to load a stored routine being executed and the other thread
tries to drop the stored routine schema.

This condition race window exists in implementation of function
mysql_change_db() called by db_load_routine() during loading of stored
routine to cache. Function mysql_change_db() calls check_db_dir_existence()
that might failed because specified database was dropped during concurrent
execution of DROP SCHEMA statement. db_load_routine() calls mysql_change_db()
with flag 'force_switch' set to 'true' value so when referenced db is not found
then my_error() is not called and function mysql_change_db() returns ok.
This shadows information about schema opening error in db_load_routine().
Then db_load_routine() makes attempt to parse stored routine that is failed.
This makes to return error to sp_cache_routines_and_add_tables_aux() but since
during error generation a call to my_error wasn't made and hence
THD::main_da wasn't set we set the generic "mysql.proc table corrupt" error
when running sp_cache_routines_and_add_tables_aux().

The fix is to install an error handler inside db_load_routine() for
the mysql_op_change_db() call, and check later if the ER_BAD_DB_ERROR
was caught.

approved by: Marko
rb://681

Coalescing of free buf_page_t descriptors can prove to be one severe
bottleneck in performance of compression. One such workload where it
hurts badly is DROP TABLE. This patch removes buf_page_t allocations
from buf_buddy and uses ut_malloc instead.
In order to further reduce overhead of colaescing we no longer attempt
to coalesce a block if the corresponding free_list is less than 16 in
size.

This patch fixes a typo in a YaSSL error message.

TO POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
 
ALTER TABLE MODIFY/CHANGE ... FIRST did nothing except renaming
columns if new version of the table had exactly the same 
structure as the old one (i.e. as result of such statement, names 
of columns changed their order as specified but data in columns 
didn't). The same thing happened for ALTER TABLE DROP COLUMN/ADD 
COLUMN statements which were supposed to produce new version of
table with exactly the same structure as the old version of table.
I.e. in the latter case the result was the same as if old column 
was renamed instead of being dropped and new column with default
as value being created.
 
Both these problems were caused by the fact that ALTER TABLE
implementation incorrectly interpreted both these situations as 
simple renaming of columns and assumed that in-place ALTER TABLE
algorithm could have been used for them.
 
This patch fixes this problem by ensuring that in cases when some
column is moved to the first position or some column is dropped
the default ALTER TABLE algorithm involving table copying is 
always used. This is achieved by detecting such situations in
mysql_prepare_alter_table() and setting Alter_info::change_level
to ALTER_TABLE_DATA_CHANGED for them.

marko.makela@oracle.com-20110616072721-8bo92ctixq6eqavr

The buf_pool->zip_clean list is only needed for debugging, or for
recomputing buf_pool->page_hash when resizing the buffer pool. Buffer
pool resizing was never fully implemented. Remove the resizing code,
and define buf_pool->zip_clean only in debug builds.

buf_pool->zip_clean, buf_LRU_insert_zip_clean(): Enclose in
#if defined UNIV_DEBUG || UNIV_BUF_DEBUG.

buf_chunk_free(), buf_chunk_all_free(), buf_pool_shrink(),
buf_pool_page_hash_rebuild(), buf_pool_resize(): Remove (unreachable code).

rb:671 approved by Inaam Rana

There is an apparent problem with page_zip_clear_rec().
In btr_cur_optimistic_update() we do this:

	page_cur_delete_rec(page_cursor, index, offsets, mtr);
...
	rec = btr_cur_insert_if_possible(cursor, new_entry, 0/*n_ext*/, mtr);
	ut_a(rec); /* <- We calculated above the insert would fit */

The problem is that page_cur_delete_rec() could fill the modification
log while doing page_zip_clear_rec(), requiring recompression for the
btr_cur_insert_if_possible(). In a pathological case, the data could
fail to recompress.

page_zip_clear_rec(): Leave the page modification log alone. Only
clear the necessary fields.

rb:673 approved by Jimmy Yang

Replace UNIV_BLOB_NULL_DEBUG with UNIV_DEBUG||UNIV_BLOB_LIGHT_DEBUG. 
Fix known bogus failures.

btr_cur_optimistic_update(): If rec_offs_any_null_extern(), assert that
the current transaction is an incomplete transaction that is being
rolled back in crash recovery.

row_build(): If rec_offs_any_null_extern(), assert that the transaction
that last updated the record was recovered during crash recovery
(and will soon be rolled back).

btr_cur_compress_if_useful(), btr_compress(): Add the parameter ibool
adjust. If adjust=TRUE, adjust the cursor position after compressing
the page.

btr_lift_page_up(): Return a pointer to the father page.

BTR_KEEP_POS_FLAG: A new flag for btr_cur_pessimistic_update().

btr_cur_pessimistic_update(): If *big_rec != NULL and flags &
BTR_KEEP_POS_FLAG, keep the cursor positioned on the updated record.
Also, do not release the index tree x-lock if *big_rec != NULL.

btr_cur_mtr_commit_and_start(): Commits and restarts a
mini-transaction so that it will retain an x-lock on index->lock and
the page of the cursor. This is invoked when
btr_cur_pessimistic_update() returns *big_rec != NULL.

In all callers of btr_cur_pessimistic_update() that do not pass
BTR_KEEP_POS_FLAG, assert that *big_rec == NULL.

btr_cur_compress(): Unused function [in the built-in MySQL 5.1], remove.

page_rec_get_nth(): Return the nth record on the page (an inverse
function of page_rec_get_n_recs_before()). Refactored from
page_get_middle_rec().

page_get_middle_rec(): Invoke page_rec_get_nth().

page_cur_insert_rec_zip_reorg(): Make use of the page directory
shortcuts in page_rec_get_nth() instead of scanning the whole list of
records.

row_ins_clust_index_entry_by_modify(): Pass BTR_KEEP_POS_FLAG to
btr_cur_pessimistic_update().

row_ins_index_entry_low(): If row_ins_clust_index_entry_by_modify()
returns a big_rec, invoke btr_cur_mtr_commit_and_start() in order to
commit and start the mini-transaction without releasing the x-locks on
index->lock and the cursor page, and write the big_rec. Releasing the
page latch in mtr_commit() caused a race condition.

row_upd_clust_rec(): Pass BTR_KEEP_POS_FLAG to
btr_cur_pessimistic_update(). If it returns a big_rec, invoke
btr_cur_mtr_commit_and_start() in order to commit and start the
mini-transaction without releasing the x-locks on index->lock and the
cursor page, and write the big_rec. Releasing the page latch in
mtr_commit() caused a race condition.

sync_thread_add_level(): Add the parameter ibool relock. When TRUE,
bypass the latching order rules.

rw_lock_add_debug_info(): For nested X-lock requests, pass relock=TRUE
to sync_thread_add_level().

rb:678 approved by Jimmy Yang

Some ut_a(!rec_offs_any_null_extern()) assertion failures are indicating
genuine BLOB bugs, others are bogus failures when rolling back incomplete
transactions at crash recovery. This needs more work, and until I get a
chance to work on it, other testing must not be disrupted by this.

revno 2995.37.209
revision id marko.makela@oracle.com-20110518120508-qhn7vz814vn77v5k
parent marko.makela@oracle.com-20110517121555-lmple24qzxqkzep4
timestamp: Wed 2011-05-18 15:05:08 +0300
message:
  Fix a bogus UNIV_SYNC_DEBUG failure in the fix of Bug #59641
  or Oracle Bug #11766513.

  trx_undo_free_prepared(): Do not acquire or release trx->rseg->mutex.
  This code is invoked in the single-threaded part of shutdown, therefore
  a mutex is not needed.

SYNTAX TRIGGERS IN ANY WAY

Table with triggers which were using deprecated (5.0-only) syntax became
unavailable for any DML and DDL after upgrade to 5.1 version of server.
Attempt to execute any statement on such a table resulted in parsing
error reported. Since this included DROP TRIGGER and DROP TABLE
statements (actually, the latter was allowed but was not functioning
properly for such tables) it was impossible to fix the problem without
manual operations on .TRG and .TRN files in data directory.

The problem was that failure to parse trigger body (due to 5.0-only
syntax) when opening trigger file for a table prevented the table
from being open. This made all operations on the table impossible
(except DROP TABLE which due to peculiarity in its implementation
dropped the table but left trigger files around).

This patch solves this problem by silencing error which occurs when
we parse trigger body during table open. Error message is preserved
for the future use and table is marked as having a broken trigger.
We also try to analyze parse tree to recover trigger name, which
will be needed in order to drop the broken trigger. DML statements
which invoke triggers on the table marked as having broken trigger
are prohibited and emit saved error message. The same happens for
DDL which change triggers except DROP TRIGGER and DROP TABLE which
try their best to do what was requested. Table becomes no longer
marked as having broken trigger when last such trigger is dropped.

row_build(): The record may contain null BLOB pointers when the server
is rolling back an insert that was interrupted by a server crash.

THE EVENT STATUS.

Any ALTER EVENT statement on a disabled event enabled it back
(unless this ALTER EVENT statement explicitly disabled the event).

The problem was that during processing of an ALTER EVENT statement
value of status field was overwritten unconditionally even if new
value was not specified explicitly. As a consequence this field
was set to default value for status which corresponds to ENABLE.

The solution is to check if status field was explicitly specified in
ALTER EVENT statement before assigning new value to status field.

If UNIV_DEBUG or UNIV_BLOB_LIGHT_DEBUG is enabled, add
!rec_offs_any_null_extern() assertions, ensuring that records do not
contain null pointers to externally stored columns in inappropriate
places.

btr_cur_optimistic_update(): Assert !rec_offs_any_null_extern().
Incomplete records must never be updated or deleted. This assertion
will cover also the pessimistic route.

row_build(): Assert !rec_offs_any_null_extern(). Search tuples must
never be built from incomplete index entries.

row_rec_to_index_entry(): Assert !rec_offs_any_null_extern() unless
ROW_COPY_DATA is requested. ROW_COPY_DATA is used for
multi-versioning, and therefore it might be valid to copy the most
recent (uncommitted) version while it contains a null pointer to
off-page columns.

row_vers_build_for_consistent_read(),
row_vers_build_for_semi_consistent_read(): Assert !rec_offs_any_null_extern()
on all versions except the most recent one.

trx_undo_prev_version_build(): Assert !rec_offs_any_null_extern() on
the previous version.

rb:682 approved by Sunny Bains

Problem: in case of wrong data insert into indexed GEOMETRY fields 
(e.g. NULL value for a not NULL field) MyISAM reported 
"ERROR 126 (HY000): Incorrect key file for table; try to repair it"
due to misuse of the key deletion function.

Fix: always use R-tree key functions for R-tree based indexes
and B-tree key functions for B-tree based indexes.

  FAIL IN EMBEDDED SERVER

FreeBSD 64 bit needs the FP_X_DNML to fpsetmask() to prevent exceptions from
propagating into mysql (as a threaded application).
However fpsetmask() itself is deprecated in favor of fedisableexcept().
1. Fixed the #ifdef to check for FP_X_DNML instead of i386.
2. Added a configure.in check for fedisableexcept() and, if present,
   this function is called insted of the fpsetmask().
No need for new tests, as the existing tests cover this already.
Removed the affected tests from the experimental list.

The problem is that clients implementing the 4.0 version of the
protocol (that is, mysql-4.0) do not null terminate a string
at the end of the authentication packet. These clients denote
the end of the string with the end of the packet.

Although this goes against the documented (see MySQL Internals
ClientServer Protocol wiki) description of the protocol, these
old clients still need to be supported.

The solution is to support the documented and actual behavior
of the clients. If a client is using the pre-4.1 version of
the protocol, the end of a string in the authentication packet
can either be denoted with a null character or by the end of
the packet. This restores backwards compatibility with old
clients implementing either the documented or actual behavior.

The problem is that although AIX implements bzero, its prototype
is not declared by default. Since AC_CHECK_FUNC(bzero) succeeds
even though a prototype is not declared, this breaks compilation
in C++ files where a prototype is required.

The solution is to only use bzero if a prototype is also declared.

will create multiple running events.

A CREATE IF NOT EXIST on an event that existed and was enabled caused
multiple instances of the event to run. Disabling the event didn't  help.
If the event was  dropped, the event stopped running, but when created
again, multiple instances of the event were still running. The only way
to get out of this situation was  to restart the server.

The problem was that Event_db_repository::create_event() didn't return
enough information to discriminate between situation when event didn't
exist and was created and when event did exist and was not created
(but a warning was emitted). As result in the latter case event
was added to in-memory queue of events second time. And this led to
unwarranted multiple executions of the same event.

The solution is to add out-parameter to Event_db_repository::create_event()
method which will signal that event was not created because it already
exists and so it should not be added to the in-memory queue.

HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".

Attempt to update an InnoDB temporary table under LOCK TABLES
led to assertion failure in both debug and production builds
if this temporary table was explicitly locked for READ. The 
same scenario works fine for MyISAM temporary tables.

The assertion failure was caused by discrepancy between lock 
that was requested on the rows of temporary table at LOCK TABLES
time and by update operation. Since SQL-layer requested a 
read-lock at LOCK TABLES time InnoDB engine assumed that upcoming
statements which are going to be executed under LOCK TABLES will 
only read table and therefore should acquire only S-lock.
An update operation broken this assumption by requesting X-lock.

Possible approaches to fixing this problem are:

1) Skip locking of temporary tables as locking doesn't make any
   sense for connection-local objects.
2) Prohibit changing of temporary table locked by LOCK TABLES ... 
   READ.

Unfortunately both of these approaches have drawbacks which make 
them unviable for stable versions of server.

So this patch takes another approach and changes code in such way
that LOCK TABLES for a temporary table will always request write
lock. In 5.1 version of this patch switch from read lock to write
lock is done inside of InnoDBs handler methods as doing it on 
SQL-layer causes compatibility troubles with FLUSH TABLES WITH
READ LOCK.

Problem: MYSQL_BIN_LOG::reset_logs acquires mutexes in wrong order.
The correct order is first LOCK_thread_count and then LOCK_log. This function
does it the other way around. This leads to deadlock when run in parallel
with a thread that takes the two locks in correct order. For example, a thread
that disconnects will take the locks in the correct order.
Fix: change order of the locks in MYSQL_BIN_LOG::reset_logs:
first LOCK_thread_count and then LOCK_log.

Assertion happens due to missing NULL value check in
Item_func_round::fix_length_and_dec() function.
The fix: added NULL value check for second parameter.

when selecting from I_S and views exist, in SP.

Symptoms: re-execution of prepared statement (or statement in a stored
routine) which read from one of I_S tables and which in order to fill
this I_S table had to open a view led to increasing memory consumption.

What happened in this situation was that during the process of view
opening for purpose of I_S filling view-related structures (like its
LEX) were allocated on persistent MEM_ROOT of prepared statement (or 
stored routine). Since this MEM_ROOT is not freed until prepared
statement deallocation (or expulsion of stored routine from the cache)
and code responsible for filling I_S is not able to re-use results of
view opening from previous executions this allocation ended up in
memory hogging.

This patch solves the problem by ensuring that when a view opened
for the purpose of I_S filling all its structures are allocated on
non-persistent runtime MEM_ROOT. This is achieved by activating a
temporary Query_arena bound to this MEM_ROOT.
Since this step makes impossible linking of view structures into
LEX of our prepared statement (or stored routine statement) this
patch also changes code filling I_S table to install a proxy LEX
before trying to open a view or a table. Consequently some code
which was responsible for backing-up/restoring parts of LEX when
view/table was opened during filling of I_S table became redundant
and was removed.

This patch doesn't contain test case for this bug as it is hard
to test memory hogging in our test suite.

Automerge mysql-5.1-gca into latest mysql-5.1.