stop/start slave
      
When stopping and restarting the slave while it is replicating
temporary tables, the server would crash or raise an assertion
failure. This was due to the fact that although temporary tables are
saved between slave threads restart, the reference to the thread in
use (table->in_use) was not being properly updated when the restart
happened (it would still reference the old/invalid thread instead of
the new one).
      
This patch addresses this issue by resetting the reference to the new
slave thread on slave thread restart.

Created new .test file - mysqldump_restore that does test restore from mysqldump
output for a limited number of basic cases.
Create new .inc file - mysqldump.inc - renames original table and uses mysqldump
output to recreate the table, then uses diff_tables.inc to compare the two tables.
Backported include/diff_tables.inc to facilitate this testing.
New patch incorporating review feedback prior to push.

mysqldump.test - removed redundant call to include/have_log_bin.inc (was used twice in the test!)

            assertion .\filesort.cc, line 797

Minor fix to test case (embedded server failure).

            assertion .\filesort.cc, line 797

A query with the "ORDER BY @@some_system_variable" clause,
where @@some_system_variable is NULL, causes assertion
failure in the filesort procedures.

The reason of the failure is in the value of
Item_func_get_system_var::maybe_null: it was unconditionally
set to false even if the value of a variable was NULL.

Created new .test file - mysqldump_restore that does this for a limited number
of basic cases.
Created new .inc file - mysqldump.inc - renames original table and uses mysqldump
output to recreate the table, then uses diff_tables.inc to compare the two tables.
Backported include/diff_tables.inc to facilitate this testing.

Since max_allowed_packet is a read-only variable in 5.1 and up,
disable warnings to avoid unnecessary test case complication.

Set max_allowed_packet to get a consistent error message.

        bug#44766: valgrind error when using convert() in a subquery

Problem: input and output buffers may be the same 
converting a string to some charset. 
That may lead to wrong results/valgrind warnings.  

Fix: use different buffers.

             warnings after uncompressed_length 
 
UNCOMPRESSED_LENGTH() did not validate its argument. In 
particular, if the argument length was less than 4 bytes, 
an uninitialized memory value was returned as a result. 
 
Since the result of COMPRESS() is either an empty string or 
a 4-byte length prefix followed by compressed data, the bug was 
fixed by ensuring that the argument of UNCOMPRESSED_LENGTH() is 
either an empty string or contains at least 5 bytes (as done in 
UNCOMPRESS()). This is the best we can do to validate input 
without decompressing. 

Change the warning message to 'Statement may not be safe to log in
statement format' to indicate that the decision on whether a
statement is safe or not is heuristic, and we are conservative.

Internal InnoDN FK parser does not recognize '\'' as quotation symbol.
Suggested fix is to add '\'' symbol check for quotation condition
(dict_strip_comments() function).

           with a "HAVING" clause though query works

SELECT from views defined like:

  CREATE VIEW v1 (view_column)
    AS SELECT c AS alias FROM t1 HAVING alias

fails with an error 1356:
  View '...' references invalid table(s) or column(s)
  or function(s) or definer/invoker of view lack rights
  to use them


CREATE VIEW form with a (column list) substitutes
SELECT column names/aliases with names from a
view column list.
However, alias references in HAVING clause was
not substituted.


The Item_ref::print function has been modified
to write correct aliased names of underlying
items into VIEW definition generation/.frm file.

The RAND(N) function where the N is a field of "constant" table
(table of single row) failed with a SIGFPE.

Evaluation of RAND(N) rely on constant status of its argument.
Current server "seeded" random value for each constant argument
only once, in the Item_func_rand::fix_fields method.
Then the server skipped a call to seed_random() in the
Item_func_rand::val_real method for such constant arguments.

However, non-constant state of an argument may be changed
after the call to fix_fields, if an argument is a field of
"constant" table. Thus, pre-initialization of random value
in the fix_fields method is too early.


Initialization of random value by seed_random() has been
removed from Item_func_rand::fix_fields method.
The Item_func_rand::val_real method has been modified to
call seed_random() on the first evaluation of this method
if an argument is a function.

Fix bug in mtr_cases.pm script visible only when InnoDB isn't configured.

Occasionally, if both the partition_pruning
and partition_range tests are run sequentially
against the IBMDB2I engine, the partition_range
test will fail.

Compiler padding on a 64-bit build allowed
garbage data in the hash key used for
caching open iconv descriptors. As a
result, cached descriptors were not found,
and multiple duplicate iconv descriptors
were opened for a single character set.
Eventually, the maximum number of open
iconv descriptors was reached, and further
iconv_open() calls would fail, leading the
storage engine to report incorrectly that
the character set was not supported.

This patch widens the 16-bit members of the
hash key to 32 bits to eliminate compiler
padding. The entire length of the hash key
is now initialized correctly on both 32-bit
and 64-bit builds.

In order to better support the usage of
IBMDB2I tables from within RPG programs,
the storage engine should ensure that the
RCDFMT name is consistent and predictable
for DB2 tables.

This patch appends a "RCDFMT <name>"
clause to the CREATE TABLE statement
that is passed to DB2.  <name> is
generated from the original name of
the table itself. This ensures a
consistent and deterministic mapping
from the original table.

For the sake of simplicity only
the alpha-numeric characters are
preserved when generating the new
name, and these are upper-cased;
other characters are replaced with
an underscore (_). Following DB2
system identifier rules, the name
always begins with an alpha-character
and has a maximum of ten characters.
If no usable characters are found in
the table name, the name X is used.