This allows the user to create duplicates of existing replication slots,
either logical or physical, and even changing properties such as whether
they are temporary or the output plugin used.
There are multiple uses for this, such as initializing multiple replicas
using the slot for one base backup; when doing investigation of logical
replication issues; and to select a different output plugins.
Author: Masahiko Sawada
Reviewed-by: Michael Paquier, Andres Freund, Petr Jelinek
Discussion: https://postgr.es/m/CAD21AoAm7XX8y_tOPP6j4Nzzch12FvA1wPqiO690RCk+uYVstg@mail.gmail.com
This was broken in commit 9c7d06d606, which inadvertently gave the
wrong value to fast_forward in one StartupDecodingContext call. Fix by
flipping the value. Add a test for the obvious error, namely trying to
initialize a replication slot with an nonexistent output plugin.
While at it, move the CreateDecodingContext call earlier, so that any
errors are reported before sending the CopyBoth message.
Author: Dave Cramer <davecramer@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CADK3HHLVkeRe1v4P02-5hj55H3_yJg3AEtpXyEY5T3wuzO2jSg@mail.gmail.com
Such replication slots are physical slots freshly created without WAL
being reserved, which is the default behavior, which have not been used
yet as WAL consumption resources to retain WAL. This prevents advancing
a slot to a position older than any WAL available, which could falsify
calculations for WAL segment recycling.
This also cleans up a bit the code, as ReplicationSlotRelease() would be
called on ERROR, and improves error messages.
Reported-by: Kyotaro Horiguchi
Author: Michael Paquier
Reviewed-by: Andres Freund, Álvaro Herrera, Kyotaro Horiguchi
Discussion: https://postgr.es/m/20180626071305.GH31353@paquier.xyz
Ability to advance both physical and logical replication slots using a
new user function pg_replication_slot_advance().
For logical advance that means records are consumed as fast as possible
and changes are not given to output plugin for sending. Makes 2nd phase
(after we reached SNAPBUILD_FULL_SNAPSHOT) of replication slot creation
faster, especially when there are big transactions as the reorder buffer
does not have to deal with data changes and does not have to spill to
disk.
Author: Petr Jelinek
Reviewed-by: Simon Riggs
Fix the tests on slow machines (per buildfarm).
Add test for dropping on error. And also try to consume real changes
from temporary slots.
From: Petr Jelinek <petr.jelinek@2ndquadrant.com>
This test, just added in commit a924c327e, sometimes fails because
the old backend hasn't finished dropping the temporary replication slot
when the new backend looks. Borrow the previously-invented methodology
for waiting for the old process to disappear from pg_stat_activity.
Petr Jelinek
Discussion: https://postgr.es/m/62935e6f-4f1b-c433-e0fa-7f936a38b3e5@2ndquadrant.com
This allows creating temporary replication slots that are removed
automatically at the end of the session or on error.
From: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Peter Eisentraut
Alvaro Herrera
Michael Paquier
Simon Riggs
Andres Freund
Peter Eisentraut
Tom Lane