Re: Deadlock detected

Hi Tom,


"Brian J. France" <postgresql@firehawksystems.com> writes:
    I am getting a few of these errors in my web logs and didn't know what I could do to stop it.
    NOTICE:  Deadlock detected -- See the lock(l) manual page for a possible cause.
      Error in query "UPDATE <table> SET <field> = <value> WHERE <field2> = <value2>" :
ERROR: WaitOnLock: error on wakeup - Aborting this transaction 
        Is this due to the hash index on field2 or due to the has index in general?
          Don't use hash indexes for concurrent applications.  I don't really knowof any reason for preferring a hash
indexover a btree index in any case.            regards, tom lane 

Could you expand a little on the subject of Hash Vs BTree indexes? And in
particular "Don't use hash indexes for concurrent applications".

I posted a question about deadlocks a week or two ago and I was advised to upgrade to 7.0.3 (from 7.0.2).
I did, but I still get a few deadlocks (i.e. all the backends eventually remain locked in requests).

I am using a lot of Hash indexes because they usually provide faster access
to a specific record than binary trees (O Vs OlogN). Most of my requests
simply lookup a record based on some specific account or transaction ID.

If using BTree instead of Hash indexes does not affect performance and solves my deadlock problem,  please let me
know!

Thanks.

--Maurice