hsenid becomes mysql enterprise gold partner

Nice to see hsenid becomes mysql enterprise gold partner. I feel we should have become this mush earlier than now since we have been using mysql heavily in our applications for long time. I think we have a good bunch of people in both our development and support teams who have experience in mysql.
I hope this move will give extra boost on our engineers and they will focus more and more on mysql expertises further.

Funny answers in mysql for IS NULL queries

Have you seen mysql returns non-NULL values for NULL query. If not you can try this out.
create table null_test(a int not null auto_increment, b int not null, primary key (a));
insert into null_test(a, b) values (0, 1); select * from null_test where a is null;

           | a | b |
        +---+---+
           | 1 | 1 |
           +---+---+
Then retry  mysql> select * from null_test where a is null;
Empty set (0.00 sec)
You can prevent this by 

• setting sql mode to NO_AUTO_VALUE_ON_ZERO. (Then next sequence number is generated only when NULL value for column is inserted.)

• And setting off SQL_AUTO_IS_NULL server variable. (When ON it returns last inserted row for a table that contains an AUTO_INCREMENT column.)

This behavior is useful for ODBC programs, such as Access. But when such mysql table is restored from a dump, data become different.

Determine Resource Usage for a SQL session

Now we can use profiling session variable to determine resource usage for a sql session.
It is introduced in mysql 5.0.37.
All the information of variable usage can be found at
http://dev.mysql.com/doc/refman/5.0/en/show-profiles.html

This gives an idea of information can be extracted from the variable.

mysql> SHOW PROFILE CPU FOR QUERY 2;

+----------------------+----------+----------+------------+

| Status               | Duration | CPU_user | CPU_system |

+----------------------+----------+----------+------------+

| checking permissions | 0.000040 | 0.000038 |   0.000002 |

| creating table       | 0.000056 | 0.000028 |   0.000028 |

| After create         | 0.011363 | 0.000217 |   0.001571 |

| query end            | 0.000375 | 0.000013 |   0.000028 |

| freeing items        | 0.000089 | 0.000010 |   0.000014 |

| logging slow query   | 0.000019 | 0.000009 |   0.000010 |

| cleaning up          | 0.000005 | 0.000003 |   0.000002 |

+----------------------+----------+----------+------------+

All the profiling information is stored in PROFILING table in INFORMATION_SCHEMA database. More details can be extracted by directly querying the table.
http://dev.mysql.com/doc/refman/5.0/en/profiling-table.html

As this information is session based, they will be lost when session ends.
Profiling information will be very useful for estimating performance of mysql queries.