7.2 occupy big hard disk space

Hi,
I use Postgresql 7.0.2 in my data logging
application system, I have to vacuum data base
every 8 hours because of many UPDATE requests. The
data base is going well except that a big pg_log file,
anyway I can accept it.

Recently, I got a new computer to porting my
application system. I install PostgreSQL 7.2 + RH 7.2
ext3 file system. Everything seems fine (pg_xlog
contains 7 files, size=16777216 bytes), but I find my
data base occupied a terribly big space in in the hard
disk (PGDATA=/by2db), it almost 4 times of the old
one(7.0.2):

postgreSQL 7.2

[sflee(at)by2cpua_1:/home/sflee]$ df
Filesystem 1k-blocks Used Available
Use% Mounted on
/dev/sda1 6190664 3145868 2730328
54% /
/dev/sda5 4134900 1131988 2792864
29% /by2db

postgreSQL 7.0.2

[sflee(at)by2cpua:/home/sflee]$ df
Filesystem 1k-blocks Used Available
Use% Mounted on
/dev/hda1 4059377 1264212 2585117
33% /
/dev/hda5 2035606 196228 1734154
10% /by2ap
/dev/hda6 2035606 274422 1655960
14% /by2db

These two data base sever engines have the same data
base,tables,fields,tuples, requested by the same
application program and vacuum data base in the same
time.

PostgreSQL 7.0.2 has been run for almost 1 year and
PostgreSQL 7.2 only 14 days. Can anyone tell me how to
do it?

regards, S.F. Lee

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