CORE-19840 Make pub_key_hash part of PK for signature table (#1631)

Remove `signature_idx` column and use `pub_key_hash` in the primary key
instead, which simplifies the insert and `ON CONFLICT` logic, while
ensuring that we don't have issues when storing a filtered transaction
followed by a signed transaction for the same transaction id.

data/avro-schema/src/main/resources/avro/net/corda/data/ledger/persistence/PersistTransactionSignatures.avsc

@@ -9,11 +9,6 @@
       "type": "string",
       "doc": "The transaction ID, derived from the root hash of its Merkle tree"
     },
-    {
-      "name": "startingIndex",
-      "type": "int",
-      "doc": "The index to insert the new signatures from"
-    },
     {
       "name": "signatures",
       "type": {

data/db-schema/src/main/resources/net/corda/db/schema/vnode-vault/migration/ledger-utxo-creation-v5.3.xml

@@ -17,6 +17,18 @@
             <column name="transaction_id"/>
         </createIndex>
 
+        <dropPrimaryKey constraintName="utxo_transaction_signature_pkey"
+            dropIndex="true"
+            tableName="utxo_transaction_signature"
+        />
+
+        <addPrimaryKey columnNames="transaction_id, pub_key_hash"
+            constraintName="utxo_transaction_signature_pkey"
+            tableName="utxo_transaction_signature"
+        />
+
+        <dropColumn columnName="signature_idx" tableName="utxo_transaction_signature"/>
+
     </changeSet>
 
 </databaseChangeLog>

gradle.properties

@@ -5,7 +5,7 @@ cordaProductVersion = 5.3.0
 # 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 = 12
+cordaApiRevision = 13
 
 # Main
 kotlin.stdlib.default.dependency = false