CORE-17355 - Reduce number of p2p e2e sessions maintained per pair of…

… vnodes (#1307)

In order to increase our performance, this PR reduces number of p2p e2e sessions maintained per pair of vnodes:
for member <-> MGM communication reduce to 1
for member <-> member communication reduce to 1

data/config-schema/src/main/resources/net/corda/schema/configuration/p2p.linkManager/1.0/corda.p2p.linkManager.json

@@ -90,11 +90,30 @@
       "minimum": 500
     },
     "sessionsPerPeer": {
-      "description": "The number of actively maintained sessions between two peers.",
-      "type": "integer",
-      "default": 4,
+      "description": "Deprecated field, numOfSessionsPerPeer should be used instead. The number of actively maintained sessions between two peers.",
+      "type": ["integer", "null"],
+      "default": null,
       "minimum": 1
     },
+    "numOfSessionsPerPeer": {
+      "description": "The number of actively maintained sessions between two peers.",
+      "type": "object",
+      "default": {},
+      "properties": {
+        "forMgm": {
+          "description": "The number of actively maintained sessions between two peers if one of them is an MGM. Communication between an MGM and a member is not considered critical and so the default value of 1 is recommended to improve performance.",
+          "type": "integer",
+          "default": 1,
+          "minimum": 1
+        },
+        "forMembers": {
+          "description": "The number of actively maintained sessions between two peers if both peers are members. The default value of 2 is recommended because the chance of both sessions failing on the same link manager is relatively low. If high-availability is critical, R3 recommends deploying multiple link manager instances instead.",
+          "type": "integer",
+          "default": 2,
+          "minimum": 1
+        }
+      }
+    },
     "revocationCheck": {
       "type": "object",
       "default": {},

gradle.properties

@@ -9,7 +9,7 @@ cordaProductVersion = 5.2.0
 # NOTE: update this each time this module contains a breaking change
 ## NOTE: currently this is a top level revision, so all API versions will line up, but this could be moved to
 ##   a per module property in which case module versions can change independently.
-cordaApiRevision = 1
+cordaApiRevision = 2
 
 # Main
 kotlinVersion = 1.8.21