Question on inserting and querying at the same time.

I have a database table that has about 90k entries, they are all
straightfoward text, and there is only one ID field that I use as
primary key for this table.

I have two threads working on this table. One of them inserting new
content constantly, (about every second) another one idles and only
wakes up when I want to query(select) the table.

My problem is that from the log it seems to me that since the insertion
is done far frequently than query, the query thread never finishes its
job. It just hangs there for a long time until I kill it by restarting
postgresql. (Even statements like EXPLAIN ANALYZE will hang)

My question is : Is my suspicion correct? And would upgrading to 8.0 (or
any later 8.x version of postgresql) help with my specific demand?

I am using PostgreSQL 7.4.13.

Thanks


Wei