different results when inserting into different partitions of a table

[liyingnan]

I created a table with a range partition, then add a partition to it using "alter table ... add partition". When i inserted 10000 records to these two partitions, i got two different results. I used 1 seconds to insert them into the partition created by "create table... partition..." and 2 seconds the one added by "alter table...partition...".I am confused by the result.
Software enviroment:
Redhat AS3.0 (2.4.21-4.ELsmp)
mysql-5.1.16-beta.tar.gz (./configure --with-plugins=max-no-ndb --with-extra-charsets=all --with-charset=utf8)
SQL:
Create table mail (id int unsigned auto_increment not null, sender varchar(256), sender_hash bigint, receivers varchar(1024), title varchar(1024), cap_time datetime, index(sender_hash), index(cap_time), index(id))
engine = myisam default charset = utf8
partition by range (to_days(cap_time)) (partition p2007_03_14 values less than (to_days("2007_03_14") + 1));
ALTER TABLE mail ADD PARTITION (PARTITION p2007_03_15 VALUES LESS THAN (to_days("2007_03_15") + 1));

insert 10000 records into partition p2007_03_14 using 1 seconds.
insert 10000 records into partition p2007_03_15 using 2 seconds.

And I don't modify any system parameter.
Thanks a lot.



Edited 3 time(s). Last edit at 03/14/2007 07:05PM by liyingnan.