Greetings, * Bruce Momjian (bruce@xxxxxxxxxx) wrote: > On Fri, Jun 14, 2019 at 10:39:40AM -0400, Bruce Momjian wrote: > > On Fri, Jun 14, 2019 at 03:12:29PM +0200, Fabio Pardi wrote: > > > Using --size-only, tells rsync to only check the size of the blocks. > > > That is: if the block is present on the destination, and is the same > > > size as the origin, then skip. > > > > The files are _exactly_ the same on primary and standby, so we don't > > need to check anything. Frankly, it is really only doing hard linking > > of the files. > > Here is the description from our docs: > > What this does is to record the links created by pg_upgrade's > link mode that connect files in the old and new clusters on the > primary server. It then finds matching files in the standby's old > cluster and creates links for them in the standby's new cluster. > Files that were not linked on the primary are copied from the > primary to the standby. (They are usually small.) This provides > rapid standby upgrades. Unfortunately, rsync needlessly copies > files associated with temporary and unlogged tables because these > files don't normally exist on standby servers. > > The primary and standby have to be binary the same or WAL replay would > not work on the standby. (Yes, I sometimes forgot how this worked so I > wrote it down in the docs.) :-) Right- this is *not* a general process for building a replica, this is specifically *only* for when doing a pg_upgrade and *everything* is shut down when it runs, and every step is checked to ensure that there are no errors during the process. Thanks! Stephen
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