Dear Hou,
Thanks for updating the patch! I can finally come back to the thread.
Regarding the max_retain_conflict_duration, I prefer GUC approach because it has
already had a mechanism for converting unit: subscription option does not have
it.
Below part contains my comments:
01. check_new_cluster_subscription_configuration
```
@@ -2024,6 +2025,7 @@ check_new_cluster_subscription_configuration(void)
PGresult *res;
PGconn *conn;
int max_active_replication_origins;
+ int max_replication_slots;
```
I feel max_replication_slots is needed when
old_cluster.sub_retain_conflict_info is true.
02. check_old_cluster_for_valid_slots
```
+ /*
+ * The name "pg_conflict_detection" (defined as
+ * CONFLICT_DETECTION_SLOT) has been reserved for
logical
+ * replication conflict detection since PG18.
+ */
+ if (GET_MAJOR_VERSION(new_cluster.major_version) >=
1800 &&
+ strcmp(slot->slotname, "pg_conflict_detection")
== 0)
```
IIUC, we can assume that the vesion of new_cluster is same as pg_upgrade, so no
need to check the major version here.
03.
Can we add a test for upgrading subscriber node with retain_conflict_info in
004_subscription?
Best regards,
Hayato Kuroda
FUJITSU LIMITED
