"Richard" <husttripper@xxxxxxxxxxxx> writes: > 1.To add live HA to PG, I transfer WAL of a database instance(Primary node) to another database instance (standby node) at real time, and keep startup alive in standby node to recovery WAL online,so that standby node can be a hot standby. > But I got some trouble. When standby node switch to primary mode to accept connections, of course after startup initilize the WAL and exit, the postgres process ereportERROR > when mdread function enter ERROR branch, and I got message like this "could not read block X of relation X/X/X: read only Xof X bytes". I spent two days to figure out what happened, but it is too hard.Please help me. I wonder whether your problem is related to this 8.3.8 bug fix: * Force WAL segment switch during pg_start_backup() (Heikki) This avoids corner cases that could render a base backup unusable. I'd suggest updating to 8.3.latest and making sure that you are taking the base backup according to the documented procedure. The symptoms you are mentioning could definitely be caused by starting from an inconsistent backup. regards, tom lane PS: Please do not post the same question to multiple mailing lists. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general