database size growing continously

Hi All,

I use postgresql 8.3.7 as a huge queue. There is a very simple table
with six columns and two indices, and about 6 million records are
written into it in every day continously commited every 10 seconds from
8 clients. The table stores approximately 120 million records, because a
cron job daily deletes those ones are older than 20 day. Autovacuum is
on and every settings is the factory default except some unrelated ones
(listen address, authorization). But my database is growing,
characteristically ~600MByte/day, but sometimes much slower (eg. 10MB,
or even 0!!!).

I've also tried a test on another server running the same postgresql,
where 300 million record was loaded into a freshly created database,
and 25 million was deleted with single DELETE command. The 'vacuum
verbose phaseangle;' command seems to be running forever for hours:

phasor=# vacuum VERBOSE phaseangle;
INFO: vacuuming "public.phaseangle"
INFO: scanned index "i" to remove 2796006 row versions
DETAIL: CPU 9.49s/120.30u sec elapsed 224.20 sec.
INFO: scanned index "t" to remove 2796006 row versions
DETAIL: CPU 13.57s/105.70u sec elapsed 192.71 sec.
INFO: "phaseangle": removed 2796006 row versions in 24748 pages
DETAIL: CPU 0.65s/0.30u sec elapsed 39.97 sec.
INFO: scanned index "i" to remove 2795924 row versions
DETAIL: CPU 9.58s/121.63u sec elapsed 239.06 sec.
INFO: scanned index "t" to remove 2795924 row versions
DETAIL: CPU 13.10s/103.59u sec elapsed 190.84 sec.
INFO: "phaseangle": removed 2795924 row versions in 24743 pages
DETAIL: CPU 0.68s/0.28u sec elapsed 40.21 sec.
INFO: scanned index "i" to remove 2796014 row versions
DETAIL: CPU 9.65s/117.28u sec elapsed 231.92 sec.
INFO: scanned index "t" to remove 2796014 row versions
DETAIL: CPU 13.48s/103.59u sec elapsed 194.49 sec.
INFO: "phaseangle": removed 2796014 row versions in 24774 pages
DETAIL: CPU 0.69s/0.28u sec elapsed 40.26 sec.
INFO: scanned index "i" to remove 2795935 row versions
DETAIL: CPU 9.55s/119.02u sec elapsed 226.85 sec.
INFO: scanned index "t" to remove 2795935 row versions
DETAIL: CPU 13.09s/102.84u sec elapsed 194.74 sec.
INFO: "phaseangle": removed 2795935 row versions in 25097 pages
DETAIL: CPU 0.67s/0.28u sec elapsed 41.21 sec.

still running...

These are the very same problems?
Should I delete mor frequently in smaller chunks? It seems to have a
limit...

Thanks

Peter

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