n the
    <TT
CLASS="FILENAME"
>recovery.conf</TT
> file on the standby server. Normal recovery
    processing would request a file from the WAL archive, reporting failure
    if the file was unavailable.  For standby processing it is normal for
    the next WAL file to be unavailable, so the standby must wait for
    it to appear. For files ending in <TT
CLASS="LITERAL"
>.backup</TT
> or
    <TT
CLASS="LITERAL"
>.history</TT
> there is no need to wait, and a non-zero return
    code must be returned. A wai