On Sun, Aug 21, 2011 at 08:23, Dondi Michael Stroma <dstroma@xxxxxxxxx> wrote: > Hello, > > I have a question about log shipping. The documentation from > PostgreSQL 8.4, in section 24.4.4, describes how to archive partial > WAL files by using the pg_xlogfile_name_offset() function, which it > calls "record-based log shipping". Although it seems that this section > of documentation has been removed in 9.0, the capability is apparently > still there. (Of course 9.0 comes with streaming replication, but the > ability to perform archiving this way is attractive as it can be used > to replicate the database to a non-sql data storage system.) > > Well, I have successfully written an archiving script to copy the > partial WAL segments as described, but I am confused as to how I would > actually use this data for a recovery. > > Section 24.4.4 states that the "restore_command scripts still deal in > whole WAL files, so the incrementally copied data is not ordinarily > made available to the standby servers. It is of use only when the > primary dies — then the last partial WAL file is fed to the standby > before allowing it to come up." > > So how would one "feed" incrementally copied partial WAL file data to > a standby (actually a new server used for recovery) as suggested > above? Pad it with zeroes up to the normal segment limit (16Mb), and feed that. PostgreSQL will detect when the correct data ends and the padding begins. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
