On Fri, Feb 22, 2019 at 5:47 AM Jehan-Guillaume de Rorthais <j...@dalibo.com> wrote: > > On Thu, 21 Feb 2019 15:38:21 -0300 > Claudio Freire <klaussfre...@gmail.com> wrote: > > > On Tue, Feb 19, 2019 at 9:44 PM Michael Paquier <mich...@paquier.xyz> wrote: > > > > > > On Tue, Feb 19, 2019 at 04:27:02PM -0800, RSR999GMAILCOM wrote: > > > > So wanted to clarify if this procedure really requires the WAL archive > > > > location on a shared storage ? > > > > > > Shared storage for WAL archives is not a requirement. It is perfectly > > > possible to use streaming replication to get correct WAL changes. > > > Using an archive is recommended for some deployments and depending on > > > your requirements and data retention policy, still you could have > > > those archives on a different host and have the restore_command of the > > > standbyt in recovery or the archive_command of the primary save the > > > segments to it. Depending on the frequency new WAL segments are > > > generated, this depends of course. > > > > If I'm not mistaken, if you don't have WAL archive set up (a shared > > filesystem isn't necessary, but the standby has to be able to restore > > WAL segments from the archive), a few transactions that haven't been > > streamed at primary shutdown could be lost, since the secondary won't > > be able to stream anything after the primary has shut down. > > This has been fixed in 9.3. The primary node wait for all WAL records to be > streamed to the connected standbys before shutting down. Including its > shutdown > checkpoint. See: > > https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=985bd7d49726c9f178558491d31a570d47340459 > > Because a standby could disconnect because of some failure during the shutdown > process, you still need to make sure the standby-to-be-promoted received the > shutdown checkpoint though. > > > WAL archive can always be restored even without a primary running, hence > > why a WAL archive is needed. > > No. Primary does not force a WAL switch/archive during shutdown.
That's good to know, both of the above.
