Unistore : Ensure Watch works in HA mode (#94120)

* Revert "Revert "Unistore : Ensure Watch works in HA mode." (#94097)"

This reverts commit 7c3fc2f261.

* make previous_resource_version nullable

* handle nil case

pkg/storage/unified/sql/data/resource_history_insert.sql

@@ -6,6 +6,7 @@ INSERT INTO {{ .Ident "resource_history" }}
         {{ .Ident "namespace" }},
         {{ .Ident "name" }},
 
+        {{ .Ident "previous_resource_version"}},
         {{ .Ident "value" }},
         {{ .Ident "action" }}
     )
@@ -17,6 +18,7 @@ INSERT INTO {{ .Ident "resource_history" }}
         {{ .Arg .WriteEvent.Key.Namespace }},
         {{ .Arg .WriteEvent.Key.Name }},
 
+        {{ .Arg .WriteEvent.PreviousRV }},
         {{ .Arg .WriteEvent.Value }},
         {{ .Arg .WriteEvent.Type }}
     )

pkg/storage/unified/sql/data/resource_history_poll.sql

@@ -5,7 +5,8 @@ SELECT
     {{ .Ident "resource" | .Into .Response.Key.Resource }},
     {{ .Ident "name" | .Into .Response.Key.Name }},
     {{ .Ident "value" | .Into .Response.Value }},
-    {{ .Ident "action" | .Into .Response.Action }}
+    {{ .Ident "action" | .Into .Response.Action }},
+    {{ .Ident "previous_resource_version" | .Into .Response.PreviousRV }}
 
     FROM {{ .Ident "resource_history" }}
     WHERE 1 = 1

pkg/storage/unified/sql/data/resource_insert.sql

@@ -7,6 +7,7 @@ INSERT INTO {{ .Ident "resource" }}
         {{ .Ident "namespace" }},
         {{ .Ident "name" }},
 
+        {{ .Ident "previous_resource_version" }},
         {{ .Ident "value" }},
         {{ .Ident "action" }}
     )
@@ -17,6 +18,7 @@ INSERT INTO {{ .Ident "resource" }}
         {{ .Arg .WriteEvent.Key.Namespace }},
         {{ .Arg .WriteEvent.Key.Name }},
 
+        {{ .Arg .WriteEvent.PreviousRV }},
         {{ .Arg .WriteEvent.Value }},
         {{ .Arg .WriteEvent.Type }}
     )

pkg/storage/unified/sql/data/resource_version_insert.sql

@@ -8,6 +8,6 @@ INSERT INTO {{ .Ident "resource_version" }}
     VALUES (
         {{ .Arg .Group }},
         {{ .Arg .Resource }},
-        1
+        2
     )
 ;