Performance issue with Insert

I am facing some performance issue with insert into some table.

I am using postgres 8.4.x

Table is having 3 before insert trigger and one after insert trigger.

With all triggers enable it is inserting only 4-5 record per second.

But if I disable after insert trigger it is able to insert 667 records per second.

After insert trigger is recursive trigger.

My question.

How to avoid the bottleneck?

Parallel processing is possible in Postgres? How?

Please give you suggestion.  
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Thanks & regards,
JENISH VYAS