Did COPY performance regression solve in 8.4rc2?

COPY performance issue is discussed in the following threads,
and it seems the conclusion was 8.4rc2 has been improved.

http://archives.postgresql.org/pgsql-hackers/2009-06/msg01133.php

However, I didn't see difference of COPY performance between 8.4rc1
and 8.4rc2.

It seems that a COPY to 8.4rc1 or 8.4rc2 using pgbench takes about 20%
longer than it does to 8.3.0.

* Test environment
- HP Proliant DL145 G3
- CentOS 5 x86_64 (kernel 2.6.18-8.1.8.el5)

* Test method
$ initdb --no-locale --encoding=UTF8
$ pg_ctl -w start
$ time pgbench -i -s 1000

* Changes of postgresql.conf
- max_connections = 200
- shared_buffers = 128MB
- logging_collector = on
- silent_mode = on

* results
8.4rc2
real 28m42.437s
real 28m33.411s
real 28m28.136s

8.4rc1
real 28m46.542s
real 29m10.575s
real 28m44.006s

8.3.0
real 23m39.131s
real 23m40.655s
real 23m49.458s

Thanks,

--
Toshihiro Kitagawa <kitagawa(at)sraoss(dot)co(dot)jp>
SRA OSS, Inc. Japan