unnecessarily
      
The problem is that libmysqlclient.so is built with THREAD
undefined, while a client compiling against the same header
files will see THREAD as defined and definitions in
my_pthread.h will be included, possibly resulting in undefined
symbols that cannot be resolved with libmysqlclient.so.
      
The suggested solution is to require that clients wanting to
link with libmysqlclient.so should be built with
MYSQL_CLIENT_NO_THREADS defined. This requires a documentation
change, and more details for this will be supplied if this
patch is approved.
      
The MYSQL_CLIENT_NO_THREADS define was renamed from
UNDEF_THREADS_HACK, to get a more suitable (less suspicious)
name for the define. (The UNDEF_THREADS_HACK is retained for
backwards compatibility, though.)
      
This patch is also in anticipation of WL#4958, which will
remove this problem altogether by dropping the building of
libmysqlclient.

Item_field::fix_fields()

Added code to the .test file to skip this test on Win64 for PB2 stability.
Please remove this code when the bug is fixed.

Had attempted to disable this test on Windows only, but the nature of this bug
does not allow for this.  The master.opt file is processed before anything in 
in the actual test.  As a result, we must use disabled.def files to ensure
these tests are skipped on the problematic platforms.

Removed Windows-only code and updated the proper disabled.def files accordingly.

GHz.

Some collations were causing IBMDB2I to report
inaccurate key range estimations to the optimizer
for LIKE clauses that select substrings. This can
be seen by running EXPLAIN. This problem primarily
affects multi-byte and unicode character sets.

This patch involves substantial changes to several
modules. There are a number of problems with the
character set and collation handling. These problems
have been or are being fixed,  and a comprehensive
test has been included which should provide much
better coverage than there was before. This test
is enabled only for IBM i 6.1, because that version
has support for the greatest number of collations.

mysql-test/suite/ibmdb2i/r/ibmdb2i_collations.result:
  Bug#45803 Inaccurate estimates for partial key values with IBMDB2I
  
  result file for test case.
mysql-test/suite/ibmdb2i/t/ibmdb2i_collations.test:
  Bug#45803 Inaccurate estimates for partial key values with IBMDB2I
  
  Tests for character sets and collations. This test
  is enabled only for IBM i 6.1, because that version
  has support for the greatest number of collations.
storage/ibmdb2i/db2i_conversion.cc:
  Bug#45803 Inaccurate estimates for partial key values with IBMDB2I
  
  - Added support in convertFieldChars to enable records_in_range
    to determine how many substitute characters were inserted and
    to suppress conversion warnings.
  
  - Fixed bug which was causing all multi-byte and Unicode fields
    to be created as UTF16 (CCSID 1200) fields in DB2. The corrected
    code will now create UCS2 fields as UCS2 (CCSID 13488), UTF8
    fields (except for utf8_general_ci) as UTF8 (CCSID 1208), and
    all other multi-byte or Unicode fields as UTF16.  This will only
    affect tables that are newly created through the IBMDB2I storage
    engine. Existing IBMDB2I tables will retain the original CCSID
    until recreated. The existing behavior is believed to be
    functionally correct, but it may negatively impact performance
    by causing unnecessary character conversion. Additionally, users
    accessing IBMDB2I tables through DB2 should be aware that mixing 
    tables created before and after this change may require extra type
    casts or other workarounds.  For this reason, users who have
    existing IBMDB2I tables using a Unicode collation other than
    utf8_general_ci are encouraged to recreate their tables (e.g.
    ALTER TABLE t1 ENGINE=IBMDB2I) in order to get the updated CCSIDs
    associated with their DB2 tables.
  
  - Improved error reporting for unsupported character sets by forcing
    a check for the iconv conversion table at table creation time,
    rather than at data access time.
storage/ibmdb2i/db2i_myconv.h:
  Bug#45803 Inaccurate estimates for partial key values with IBMDB2I
  
  Fix to set errno when iconv fails.
storage/ibmdb2i/db2i_rir.cc:
  Bug#45803 Inaccurate estimates for partial key values with IBMDB2I
  
  Significant improvements were made to the records_in_range code
  that handles partial length string data in keys for optimizer plan
  estimation. Previously, to obtain an estimate for a partial key
  value, the implementation would perform any necessary character
  conversion and then attempt to determine the unpadded length of
  the partial key by searching for the minimum or maximum sort
  character. While this algorithm was sufficient for most single-byte
  character sets, it did not treat Unicode and multi-byte strings
  correctly. Furthermore, due to an operating system limitation,
  partial keys having UTF8 collations (ICU sort sequences in DB2)
  could not be estimated with this method.
  
  With this patch, the code no longer attempts to explicitly determine
  the unpadded length of the key. Instead, the entire key is converted
  (if necessary), including padding, and then passed to the operating
  system for estimation. Depending on the source and target character
  sets and collations, additional logic is required to correctly
  handle cases in which MySQL uses unconvertible or differently
  -weighted values to pad the key. The bulk of the patch exists
  to implement this additional logic.
storage/ibmdb2i/ha_ibmdb2i.h:
  Bug#45803 Inaccurate estimates for partial key values with IBMDB2I
  
  The convertFieldChars declaration was updated to support additional 
  optional behaviors.

timeout
            
In STMT and MIXED modes, a statement that changes both non-transactional and
transactional tables must be written to the binary log whenever there are
changes to non-transactional tables. This means that the statement gets into the
binary log even when the changes to the transactional tables fail. In particular
, in the presence of a failure such statement is annotated with the error number
and wrapped in a begin/rollback. On the slave, while applying the statement, it
is expected the same failure and the rollback prevents the transactional changes
to be persisted.
            
Unfortunately, statements that fail due to concurrency issues (e.g. deadlocks,
timeouts) are logged in the same way causing the slave to stop as the statements
are applied sequentially by the SQL Thread. To fix this bug, we automatically
ignore concurrency failures on the slave. Specifically, the following failures
are ignored: ER_LOCK_WAIT_TIMEOUT, ER_LOCK_DEADLOCK and ER_XA_RBDEADLOCK.

          server

If the server connection was lost during repeated status commands,
the client would fail to detect this and the client output would be inconsistent.

This patch fixes this issue by making sure that the server is online
before the client attempts to execute the status command.


client/mysql.cc:
  * Replace variable "connected" with a call to mysql_real_query_for_lazy()
    will attempt to reconnect to server on if there is a failure.

The crash happend because for views which are joins
we have table_list->table == 0 and 
table_list->table->'any method' call leads to crash.
The fix is to perform table_list->table->file->extra()
method for all tables belonging to view.


mysql-test/r/view.result:
  test result
mysql-test/t/view.test:
  test case
sql/sql_insert.cc:
  added prepare_for_positional_update() function
  which updates extra info about primary key for
  tables belonging to view.

enabled message storing into error message list
for 'drop table' command


mysql-test/r/warnings.result:
  test result
mysql-test/t/warnings.test:
  test case
sql/sql_table.cc:
  We should skip error sending then we should return
  warnings to client as some functions may send its
  own errors, so we should set no_warnings_for_error= 0
  only in case of warning.
  The fix is to enable message storing into error message
  list for 'drop table' command(only for error case).
tests/mysql_client_test.c:
  test fix