Add prepare API support for streaming transactions in logical replication.

Commit a8fd13cab0 added support for prepared transactions to built-in
logical replication via a new option "two_phase" for a subscription. The
"two_phase" option was not allowed with the existing streaming option.

This commit permits the combination of "streaming" and "two_phase"
subscription options. It extends the pgoutput plugin and the subscriber
side code to add the prepare API for streaming transactions which will
apply the changes accumulated in the spool-file at prepare time.

Author: Peter Smith and Ajin Cherian
Reviewed-by: Vignesh C, Amit Kapila, Greg Nancarrow
Tested-By: Haiying Tang
Discussion: https://postgr.es/m/[email protected]
Discussion: https://postgr.es/m/CAMGcDxeqEpWj3fTXwqhSwBdXd2RS9jzwWscO-XbeCfso6ts3+Q@mail.gmail.com

1 files changed, 13 insertions, 11 deletions

diff --git a/src/test/regress/expected/subscription.out b/src/test/regress/expected/subscription.out
index 67f92b38787..77b4437b693 100644
--- a/src/test/regress/expected/subscription.out
+++ b/src/test/regress/expected/subscription.out
@@ -282,27 +282,29 @@ WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ..
 --fail - alter of two_phase option not supported.
 ALTER SUBSCRIPTION regress_testsub SET (two_phase = false);
 ERROR:  unrecognized subscription parameter: "two_phase"
---fail - cannot set streaming when two_phase enabled
+-- but can alter streaming when two_phase enabled
 ALTER SUBSCRIPTION regress_testsub SET (streaming = true);
-ERROR:  cannot set streaming = true for two-phase enabled subscription
-ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
 \dRs+
                                                                      List of subscriptions
       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two phase commit | Synchronous commit |          Conninfo           
 -----------------+---------------------------+---------+-------------+--------+-----------+------------------+--------------------+-----------------------------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | p                | off                | dbname=regress_doesnotexist
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | p                | off                | dbname=regress_doesnotexist
 (1 row)
 
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
 DROP SUBSCRIPTION regress_testsub;
--- fail - two_phase and streaming are mutually exclusive.
-CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (streaming = true, two_phase = true);
-ERROR:  two_phase = true and streaming = true are mutually exclusive options
+-- two_phase and streaming are compatible.
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, streaming = true, two_phase = true);
+WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
 \dRs+
-                                            List of subscriptions
- Name | Owner | Enabled | Publication | Binary | Streaming | Two phase commit | Synchronous commit | Conninfo 
-------+-------+---------+-------------+--------+-----------+------------------+--------------------+----------
-(0 rows)
+                                                                     List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two phase commit | Synchronous commit |          Conninfo           
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+--------------------+-----------------------------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | p                | off                | dbname=regress_doesnotexist
+(1 row)
 
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
+DROP SUBSCRIPTION regress_testsub;
 RESET SESSION AUTHORIZATION;
 DROP ROLE regress_subscription_user;
 DROP ROLE regress_subscription_user2;