Hot Standby - ERROR: canceling statement due to conflict with recovery

[Sean Laurent <sean@xxxxxxxxxxxxx>]

I have a hot-standby instance setup using Postgres 9.0.1 with streaming replication against a 9.0.1 master. On the master, I have the following set in the postgresql.conf:

checkpoint_segments = 3

checkpoint_timeout = 1min

checkpoint_completion_target = 0.5

max_wal_senders = 3

wal_sender_delay = 200ms

wal_keep_segments = 1440

According to pg_controldata, everything is working on the standby:

Database cluster state:               in production

pg_control last modified:             Sun 27 Feb 2011 12:28:07 PM CST

...

Current wal_level setting:            hot_standby

Unfortunately, most queries against the hot standby fail. Worse yet, pg_dump fails:

pg_dump: SQL command failed

pg_dump: Error message from server: ERROR:  canceling statement due to conflict with recovery

DETAIL:  User query might have needed to see row versions that must be removed.

I'm not entirely certain I understand why I'm seeing this. Nor do I understand how to fix or work around this. Any advice or suggestions would be greatly appreciated.

-Sean