> The most important part is: > > 2013-09-22 09:52:47 JST[28297][51d1fbcb.6e89-2][0][XX000]FATAL: Could not > receive data from WAL stream: could not receive data from server: connection > timeout > scp: /opt/PostgresPlus/9.2AS/data/arch/000000AC000001F10000004A: No such > file or directory > > I was asked about: > In what occasion will the above fatal error occur?
It is a network error. The TCP/IP socket died somehow, and the FATAL error logged. PostgreSQL then fell back to using the restore_command defined in your recovery.conf file, but the WAL file had not yet been shipped and the output logged. I imagine streaming replication happily reconnected soon after. This is all quite normal.
