Deadlocks in 7.4.x ...

Client is running 7.4.6 right now (we're looking at moving to 7.4.8 when 
we can get a suitable ops window for the upgrade), and is experiencing 
semi-regular (10-16 times a day) deadlocks, with the following 
information:

A little background:
  1) We do not do explicit row or table locking.  2) We use serialized transactions quite often.  3) All deadlocks are
fightingfor the same relation: 4335271, which is     the tsearch2 fulltext index on the articles table:
articles_idxft1_idx. 4) I have a trigger on the articles table which is executed before     insert or update.  It
updatesthe fulltext index column if any     changes are made to the relevant article columns.  This is the only
placewhere changes are made to the fulltext index column.
 

DETAIL:  Process 8122 waits for AccessExclusiveLock on relation 4335271 of database 17142; blocked by process 11846.
Process 11846 waits for ShareLock on transaction 2897133915; blocked by process 10042.
Process 10042 waits for AccessExclusiveLock on relation 4335271 of database 17142; blocked by process 8122.
----------------------------------
DETAIL:  Process 10042 waits for AccessExclusiveLock on relation 4335271 of database 17142; blocked by process 11846.
Process 11846 waits for ShareLock on transaction 2897133915; blocked by process 10042.

I haven't had much experience (okay, I've yet to use it) with tsearch2, 
but according to 
http://www.postgresql.org/docs/8.0/interactive/limitations.html, GiST does 
have concurrency issues "The current implementation of GiST within 
PostgreSQL has some major limitations: GiST access is not concurrent"

Could this be what we are experiencing?

This is a wee bit vague, but I'm not sure what direction(s) to look at for 
Deadlocks themselves, so pointers/ideas would be much appreciated ...

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy@hub.org           Yahoo!: yscrappy              ICQ: 7615664