Re: Synchronizing slots from primary to standby

On Mon, Jan 29, 2024 at 3:11 PM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> PFA v71 patch set with above changes.
>

Few comments on 0001
===================
1.
parse_subscription_options()
{
...
/*
* We've been explicitly asked to not connect, that requires some
* additional processing.
*/
if (!opts->connect && IsSet(supported_opts, SUBOPT_CONNECT))
{

Here, along with other options, we need an explicit check for
failover, so that if connect=false and failover=true, the statement
should give error. I was expecting the below statement to fail but it
passed with WARNING.
postgres=# create subscription sub2 connection 'dbname=postgres'
publication pub2 with(connect=false, failover=true);
WARNING: subscription was created, but is not connected
HINT: To initiate replication, you must manually create the
replication slot, enable the subscription, and refresh the
subscription.
CREATE SUBSCRIPTION

2.
@@ -148,6 +153,10 @@ typedef struct Subscription
List *publications; /* List of publication names to subscribe to */
char *origin; /* Only publish data originating from the
* specified origin */
+ bool failover; /* True if the associated replication slots
+ * (i.e. the main slot and the table sync
+ * slots) in the upstream database are enabled
+ * to be synchronized to the standbys. */
} Subscription;

Let's add this new field immediately after "bool runasowner;" as is
done for other boolean members. This will help avoid increasing the
size of the structure due to alignment when we add any new pointer
field in the future. Also, that would be consistent with what we do
for other new boolean members.

--
With Regards,
Amit Kapila.