Automerge with mysql-5.1.

BUG#64503: mysql frequently ignores --relay-log-space-limit

When the SQL thread goes to sleep, waiting for more events, it sets
the flag ignore_log_space_limit to true. This gives the IO thread a
chance to queue some more events and ultimately the SQL thread will be
able to purge the log once it is rotated. By then the SQL thread
resets the ignore_log_space_limit to false. However, between the time
the SQL thread has set the ignore flag and the time it resets it, the
IO thread will be queuing events in the relay log, possibly going way
over the limit.

This patch makes the IO and SQL thread to synchronize when they reach
the space limit and only ask for one event at a time. Thus the SQL
thread sets ignore_log_space_limit flag and the IO thread resets it to
false everytime it processes one more event. In addition, everytime
the SQL thread processes the next event, and the limit has been
reached, it checks if the IO thread should rotate. If it should, it
instructs the IO thread to rotate, giving the SQL thread a chance to
purge the logs (freeing space). Finally, this patch removes the
resetting of the ignore_log_space_limit flag from purge_first_log,
because this is now reset by the IO thread every time it processes the
next event when the limit has been reached.

If the SQL thread is in a transaction, it cannot purge so, there is no
point in asking the IO thread to rotate. The only thing it can do is
to ask for more events until the transaction is over (then it can ask
the IO to rotate and purge the log right away). Otherwise, there would
be a deadlock (SQL would not be able to purge and IO thread would not
be able to queue events so that the SQL would finish the transaction).

truncating, inserting the same set of rows. When a table is 
re-created with the same set of rows, the data file size must
not grow.  

rb:968
Approved by Marko. 

This bug has been there at least since MySQL 4.0.9. (Before 4.0.9, the
code probably was even more severely broken.)

btr_pcur_restore_position(): When cursor restoration fails, before
invoking btr_pcur_store_position() move to the previous or next record
unless cursor->rel_pos==BTR_PCUR_ON or the record was not a user
record.

This bug can cause skipped records when btr_pcur_store_position() is
called on the last record of a page. A symptom would be record count
mismatch in CHECK TABLE, or failure to find a record to delete-mark or
update or purge. The following operations should be affected by the
bug:

* row_search_for_mysql(): SELECT, UPDATE, REPLACE, CHECK TABLE,
  (almost anything else than INSERT)

* foreign key CASCADE operations

* row_merge_read_clustered_index(): index creation (since MySQL 5.1
  InnoDB Plugin)

* multi-threaded purge (after MySQL 5.5): not sure, but it might fail
  to purge some records

Not all callers of btr_pcur_restore_position() should be affected.
Anything that asserts or checks that restoration succeeds is
unaffected. For example, cursor restoration on the change buffer tree
should always succeed, because access is being protected by additional
latches. Likewise, rollback, or any code accesses data dictionary
tables while holding dict_sys->mutex should be safe.

rb:967 approved by Jimmy Yang

Post-push fixes.


mysys/stacktrace.c:
  Missing comma after "%s" format specifier.
sql/mysqld.cc:
  Move #define to signal_handler.cc
sql/signal_handler.cc:
  Missing #define UNSAFE_DEFAULT_LINUX_THREADS 200

Analysis:
========================
sql_mode "NO_BACKSLASH_ESCAPES": When user want to use backslash as character input,
instead of escape character in a string literal then sql_mode can be set to 
"NO_BACKSLASH_ESCAPES". With this mode enabled, backslash becomes an ordinary 
character like any other. 

SQL_MODE set applies to the current client session. And while creating the stored 
procedure, MySQL stores the current sql_mode and always executes the stored 
procedure in sql_mode stored with the Procedure, regardless of the server SQL 
mode in effect when the routine is invoked.  

In the scenario (for which bug is reported), the routine is created with 
sql_mode=NO_BACKSLASH_ESCAPES. And routine is executed with the invoker sql_mode
is "" (NOT SET) by executing statement "call testp('Axel\'s')".
Since invoker sql_mode is "" (NOT_SET), the '\' in 'Axel\'s'(argument to function)
is considered as escape character and column "a" (of table "t1") values are 
updated with "Axel's". The binary log generated for above update operation is as below,

  set sql_mode=XXXXXX (for no_backslash_escapes)
  update test.t1 set a= NAME_CONST('var',_latin1'Axel\'s' COLLATE 'latin1_swedish_ci');

While logging stored procedure statements, the local variables (params) used in
statements are replaced with the NAME_CONST(var_name, var_value) (Internal function) 
(http://dev.mysql.com/doc/refman/5.6/en/miscellaneous-functions.html#function_name-const)

On slave, these logs are applied. NAME_CONST is parsed to get the variable and its
value. Since, stored procedure is created with sql_mode="NO_BACKSLASH_ESCAPES", the sql_mode
is also logged in. So that at slave this sql_mode is set before executing the statements
of routine.  So at slave, sql_mode is set to "NO_BACKSLASH_ESCAPES" and then while
parsing NAME_CONST of string variable, '\' is considered as NON ESCAPE character
and parsing reported error for "'" (as we have only one "'" no backslash). 

At slave, parsing was proper with sql_mode "NO_BACKSLASH_ESCAPES".
But above error reported while writing bin log, "'" (of Axel's) is escaped with
"\" character. Actually, all special characters (n, r, ', ", \, 0...) are escaped
while writing NAME_CONST for string variable(param, local variable) in bin log 
irrespective of "NO_BACKSLASH_ESCAPES" sql_mode. So, basically, the problem is 
that logging string parameter does not take into account sql_mode value.

Fix:
========================
So when sql_mode is set to "NO_BACKSLASH_ESCAPES", escaping  characters as 
(n, r, ', ", \, 0...) should be avoided. To do so, added a check to not to
escape such characters while writing NAME_CONST for string variables in bin 
log. 
And when sql_mode is set to NO_BACKSLASH_ESCAPES, quote character "'" is
represented as ''.
http://dev.mysql.com/doc/refman/5.6/en/string-literals.html (There are several 
ways to include quote characters within a string: )

Analysis:
========================
sql_mode "NO_BACKSLASH_ESCAPES": When user want to use backslash as character input,
instead of escape character in a string literal then sql_mode can be set to 
"NO_BACKSLASH_ESCAPES". With this mode enabled, backslash becomes an ordinary 
character like any other. 

SQL_MODE set applies to the current client session. And while creating the stored 
procedure, MySQL stores the current sql_mode and always executes the stored 
procedure in sql_mode stored with the Procedure, regardless of the server SQL 
mode in effect when the routine is invoked.  

In the scenario (for which bug is reported), the routine is created with 
sql_mode=NO_BACKSLASH_ESCAPES. And routine is executed with the invoker sql_mode
is "" (NOT SET) by executing statement "call testp('Axel\'s')".
Since invoker sql_mode is "" (NOT_SET), the '\' in 'Axel\'s'(argument to function)
is considered as escape character and column "a" (of table "t1") values are 
updated with "Axel's". The binary log generated for above update operation is as below,

  set sql_mode=XXXXXX (for no_backslash_escapes)
  update test.t1 set a= NAME_CONST('var',_latin1'Axel\'s' COLLATE 'latin1_swedish_ci');

While logging stored procedure statements, the local variables (params) used in
statements are replaced with the NAME_CONST(var_name, var_value) (Internal function) 
(http://dev.mysql.com/doc/refman/5.6/en/miscellaneous-functions.html#function_name-const)

On slave, these logs are applied. NAME_CONST is parsed to get the variable and its
value. Since, stored procedure is created with sql_mode="NO_BACKSLASH_ESCAPES", the sql_mode
is also logged in. So that at slave this sql_mode is set before executing the statements
of routine.  So at slave, sql_mode is set to "NO_BACKSLASH_ESCAPES" and then while
parsing NAME_CONST of string variable, '\' is considered as NON ESCAPE character
and parsing reported error for "'" (as we have only one "'" no backslash). 

At slave, parsing was proper with sql_mode "NO_BACKSLASH_ESCAPES".
But above error reported while writing bin log, "'" (of Axel's) is escaped with
"\" character. Actually, all special characters (n, r, ', ", \, 0...) are escaped
while writing NAME_CONST for string variable(param, local variable) in bin log 
Airrespective of "NO_BACKSLASH_ESCAPES" sql_mode. So, basically, the problem is 
that logging string parameter does not take into account sql_mode value.

Fix:
========================
So when sql_mode is set to "NO_BACKSLASH_ESCAPES", escaping  characters as 
(n, r, ', ", \, 0...) should be avoided. To do so, added a check to not to
escape such characters while writing NAME_CONST for string variables in bin 
log. 
And when sql_mode is set to NO_BACKSLASH_ESCAPES, quote character "'" is
represented as ''.
http://dev.mysql.com/doc/refman/5.6/en/string-literals.html (There are several 
ways to include quote characters within a string: )



mysql-test/r/sql_mode.result:
  Added test case for Bug#12601974.
mysql-test/suite/binlog/r/binlog_sql_mode.result:
  Appended result of test cases added for Bug#12601974.
mysql-test/suite/binlog/t/binlog_sql_mode.test:
  Added test case for Bug#12601974.
mysql-test/t/sql_mode.test:
  Appended result of test cases added for Bug#12601974.

row_drop_table_for_mysql(): Really flag the indexes unavailable before
starting to drop the table.

also filed as Bug#13146269, Bug#13713178

btr_get_size(): Add mtr_t parameter. Require that the caller S-latches
index->lock. If index->page==FIL_NULL or the index is to be dropped,
return ULINT_UNDEFINED to indicate that the statistics are
unavailable.

dict_update_statistics(): If btr_get_size() returns ULINT_UNDEFINED,
fake the index cardinality statistics.

dict_index_set_page(): Unused function, remove.

row_drop_table_for_mysql(): Before starting to drop the table, mark
the indexes unavailable in the data dictionary cache while holding
index->lock X-latch.

ha_innobase::prepare_drop_index(), ha_innobase::final_drop_index():
When setting index->to_be_dropped, acquire the index->lock X-latch.

rb:960 approved by Jimmy Yang

CHECK_SIMPLE_EQUALITY

PROBLEM:
Crash in "check_simple_equality" when using a subquery with "IN" and
"ALL" in prepare.

ANALYSIS:
Crash can be reproduced using a simplified query like this one:
prepare s from "select 1 from g1 where 1 < all (
                select @:=(1 in (select 1 from g1)) from g1)";

This bug is currently present only on 5.5.and 5.1. Its fixed as part
of work log(#1110) in 5.6. We are taking one change to fix this
in 5.5 and 5.1.

Problem seems to be present because we are trying to evaluate "is_null"
on an argument which is part of a subquery
(In Item_is_not_null_test::update_used_tables()).
But the condition to evaluate is only when we do not have a sub query
present, which means to say that "with_subselect" is not set.
With respect to the above query, we create an object of type
"Item_in_optimizer" which by definition is always associated with a
subquery. While in 5.6 we set "with_subselect" to true for
"Item_in_optimizer" object, we do not do the same in 5.5. This results in
the evaluation for "is_null" resulting in a coredump.
So, we are now setting "with_subselect" to true for "Item_in_optimizer"
in 5.1 and 5.5.


mysql-test/r/func_in.result:
  Result file changes for the test case added
mysql-test/t/func_in.test:
  Test case added for Bug#13012483
sql/item_cmpfunc.h:
  Changed Item_in_optimizer::Item_in_optimizer( ) to set "with_subselect"
  to true

Suppress innodb_bug34300 from failing if InnoDB prints:

  120221 11:05:03  InnoDB: ERROR: the age of the last checkpoint is 9439048,
  InnoDB: which exceeds the log group capacity 9433498.

by default the log capacity is 2 log files, 5 MB each.

                                        RESULT FROM PREVIOUS TRANSACTION

The current Query Cache API is not fully compatible with
the partitioning engine.

There is no good way to implement support for QC due to:
1) a static callback for ha_partition would need to have access
to all partition names and call the underlying callback for each
[sub]partition with the correct name.
2) pruning would be impossible, even if one used the ulonglong
engine_data due to if engine_data is changed, the table is
invalidated by the QC.

So the only viable solution to avoid incorrect data is to not allow
caching of queries using partitioned tables.

(There are some extra changes, due to removal of \r as line break)

If a query's end time is before before its start time, the system clock has been turn back
(daylight savings time etc.). When the system clock is changed, we can't tell for certain a
given query was actually slow. We did not protect against logging such a query with a bogus
execution time (resulting from end_time - start_time being negative), and possibly logging it
even though it did not really take long to run.

We now have a sanity check in place.

sql/sql_parse.cc:
  Make sure end time is not before start time - otherwise, we can be SURE the system clock
  was changed in between, but not by how much. In other words, when the clock is changed,
  we don't know how long a query ran, and whether it was slow.

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.

            
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.

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.

                      CASES RESETS DATA POINTER TO SMAL

ISSUE: Myisamchk doing sort recover
       on a table reduces data_file_length.
       Maximum size of data file decreases,
       lesser number of rows are stored.

SOLUTION: Size of data_file_length is
          fixed to the original length.

                      CASES RESETS DATA POINTER TO SMAL

ISSUE: Myisamchk doing sort recover
       on a table reduces data_file_length.
       Maximum size of data file decreases,
       lesser number of rows are stored.

SOLUTION: Size of data_file_length is
          fixed to the original length.

rb://914
approved by: Marko Makela

Poll in fil_rename_tablespace() after setting ::stop_ios flag can
result in a hang because the other thread actually dispatching the IO
won't wake IO helper threads or flush the tablespace before starting
wait in fil_mutex_enter_and_prepare_for_io().

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