From 83fee1cbfc98d90be1b7551a2802688193a2c1e2 Mon Sep 17 00:00:00 2001
From: Chris Cranford <chris@hibernate.org>
Date: Fri, 22 Jan 2021 15:35:28 -0500
Subject: [PATCH] DBZ-2949 Guard against LAST_DDL_TIME with value of 0

---
 .../oracle/OracleSnapshotChangeEventSource.java        | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/OracleSnapshotChangeEventSource.java b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/OracleSnapshotChangeEventSource.java
index 564bd9718..ea7fe00e2 100644
--- a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/OracleSnapshotChangeEventSource.java
+++ b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/OracleSnapshotChangeEventSource.java
@@ -184,7 +184,15 @@ private Optional<Long> getLatestTableDdlScn(RelationalSnapshotContext ctx) throw
                 throw new IllegalStateException("Couldn't get latest table DDL SCN");
             }
 
-            return Optional.of(rs.getLong(1));
+            // Guard against LAST_DDL_TIME with value of 0.
+            // This case should be treated as if we were unable to determine a value for LAST_DDL_TIME.
+            // This forces later calculations to be based upon the current SCN.
+            Long latestDdlTime = rs.getLong(1);
+            if (latestDdlTime != null && latestDdlTime == 0L) {
+                return Optional.empty();
+            }
+
+            return Optional.of(latestDdlTime);
         }
         catch (SQLException e) {
             if (e.getErrorCode() == 8180) {