UNION could convert fixed-point FLOAT(M,D)/DOUBLE(M,D) columns  
to FLOAT/DOUBLE when aggregating data types from the SELECT  
substatements. While there is nothing particularly wrong with  
this behavior, especially when M is greater than the hardware  
precision limits, it could be confusing in cases when all  
SELECT statements in a union have the same  
FLOAT(M,D)/DOUBLE(M,D) columns with equal precision  
specifications listed in the same position.  
  
Since the manual is quite vague on what data type should be  
returned in such cases, the bug was fixed by implementing the  
most 'expected' behavior: do not convert FLOAT(M,D)/DOUBLE(M,D)  
to anything else if all SELECT statements in a UNION have the  
same precision for that column.  

Problem: commit doesn't delete savepoints if there are no changes 
in the transaction.

Fix: delete them in such cases.

The problem is that the read and write methods of the shared
memory transport (protocol) didn't react to asynchronous close
events, which could lead to a lock up as the client would wait
(until time out) for a server response that will never come.

The solution is to also wait for close events while waiting
for I/O from or to the server.

      
When add an aliase name after NAME_CONST, the aliase name will be overwrite.
      
NAME_CONST will re-set the field's name only if there isn't an aliase in the
function fix-fields().
If there is an aliase, NAME_CONST doesn't re-set the field's name and keeps the old
name.

            
After the table is compressed by the myisampack utility,
opening the table by the server produces valgrind warnings.
      
This happens because when we try to read a record into the buffer
we alway assume that the remaining buffer to read is always equal 
to word size(4 or 8 or 2 bytes) we read. Sometimes we have 
remaining buffer size less than word size and trying to read the 
entire word size will end up in valgrind errors.
            
Fixed by reading byte by byte when we detect the remaining buffer 
size is less than the word size.

                    expired timeout on debx86-b in PB 

Moved the resource-intensive test case for bug #41486 into 
a separate test file to reduce execution time for mysql.test. 

                    produce incorrect results for ROUND() 

Added a workaround and a configure check to test whether 
isinf() is affected by the GCC bug #39228. 
       
Since no code in MySQL server is currently affected by that 
bug, the patch is actually a safeguard for possible future 
code modifications. No test cases or changelog entries are 
needed. 

When do 'insert delayed' operation, the time_zone info doesn't be keeped in the row info.
So when we do insert sometime later, time_zone didn't write into binlog.
This will cause wrong result for timestamp column in slave.

Our solution is that adding time_zone info with the delayed-row and
restoring time_zone from row-info when execute that row in the furture by another thread.
So we can write correct time_zone info into binlog and got correct result in slave.

   Details for Bug#43015 main.lock_multi: Weak code (sleeps etc.)
   -------------------------------------------------------------
   - The fix for bug 42003 already removed a lot of the weaknesses mentioned.
   - Tests showed that there are unfortunately no improvements of this tests
     in MySQL 5.1 which could be ported back to 5.0.
   - Remove a superfluous "--sleep 1" around line 195

   Details for Bug#43065 main.lock_multi: This test is too big if the disk is slow
   -------------------------------------------------------------------------------
   - move the subtests for the bugs 38499 and 36691 into separate scripts
   - runtime under excessive parallel I/O load after applying the fix
     lock_multi           [ pass ]          22887
     lock_multi_bug38499  [ pass ]         536926
     lock_multi_bug38691  [ pass ]         258498

When asking what database is selected, client expected
to *always* get an answer from the server.

We now handle failure more gracefully.

See comments in ticket for a discussion of what happens,
and how things interlock.

Don't compare string literals as it results in unspecified behavior.

functions
      
Unknown timezone specifications are properly rejected
by the server, but are copied into tz_storage before
rejection, and hence is retained until end of server 
life. With sufficiently large bogus timezone specs, 
it is easy to exhaust system memory.
      
Allocation of memory for a copy of the timezone
name is delayed until after verification of validity,
at the cost of a memcpy of the timezone info. This 
only happens once, future lookups will hit the cached
structure.

for bug #41486. Session max_allowed_packet is read-only
as of MySQL 5.1.31. In addition, the global variable
now has no effect on the current session.

fixed help message

Don't throw an error after checking the first and the second arguments.
Continue with checking the third and higher arguments and if some of
them is stronger according to coercibility rules,
then this argument's collation is set as result collation.

                        
When loading dump created by mysqldump tool an error is
thrown saying storage engine for the table doesn't have 
an option.
                        
mysqldump tries to re-insert the data into the federated
table which causes the error. Since the data is already
available on the remote server, mysqldump shouldn't try
to dump the data again for FEDERATED tables.
                        
As stated in the bug page, it can be considered similar
to the MERGE ENGINE with "view only" nature.
                        
Fixed by adding the "FEDERATED ENGINE" to the exception
list to ignore the data.

                   ~40Mb after mysqldump/import 
        
When the input string exceeds the maximum allowed size for the 
internal buffer, batch_readline() returns a truncated string. 
Since there was no way for a caller to determine whether the 
string was truncated or not, the command line client assumed 
batch_readline() to always return the whole input string and 
appended a newline character. This resulted in garbled data 
when importing dumps containing strings longer than the 
maximum input buffer size. 
  
Fixed by adding a flag to the batch_readline() interface to 
signal a truncated string to the caller. 
  
Other minor problems fixed during patch implementation: 
 
- The maximum allowed buffer size for batch_readline() was set 
up depending on the client's max_allowed_packet value. It does 
not actully make any sense, as those variables are not 
related. The input buffer size limit is now always set to 1 
MB. 
  
- fill_buffer() did not always set the EOF flag. 
 
- The input buffer could actually grow twice as the specified 
limit due to insufficient checks in intern_read_line(). 

Revised patch incorporating cleaner test code brought up during review.
Removed the use of grep and accomplished same actions via SQL / use of the server.

Runs as before on *nix systems and now runs on Windows without Cygwin as well.

seems to become negative

THD::start_time has a dual meaning : it's either the time since the process
entered a given state or is the transaction time returned by e.g. NOW().
This causes problems, as sometimes THD::start_time may be set to a value
that is correct and needed when used as a base for NOW(), but these times
may be arbitrary (SET @@timestamp) or non-local (coming from the master 
through the replication feed).
If one such non-local time is set there's no way to return a correct value
for e.g. SHOW PROCESSLIST or SELECT ... FROM INFORMATION_SCHEMA.PROCESSLIST.
Fixed by making the Time column in SHOW PROCESSLIST SIGNED LONG instead of 
UNSIGNED LONG and doing the correct conversions.
      
Note that no reliable test suite can be constructed, since it would require
knowing the local time and can't be achieved by the means of the current test
suite.