diff --git a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerMetrics.java b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerMetrics.java
index c769b70d2..dbe34bb80 100644
--- a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerMetrics.java
+++ b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerMetrics.java
@@ -40,7 +40,7 @@ public class LogMinerMetrics extends Metrics implements LogMinerMetricsMXBean {
     LogMinerMetrics(CdcSourceTaskContext taskContext) {
         super(taskContext, "log-miner");
 
-        maxBatchSize.set(2000);
+        maxBatchSize.set(5_000);
         millisecondToSleepBetweenMiningQuery.set(1000);
         fetchedRecordSizeLimitToFallAsleep.set(50);
 
@@ -161,7 +161,7 @@ public int getFetchedRecordSizeLimitToFallAsleep() {
     // MBean accessible setters
     @Override
     public void setMaxBatchSize(int size) {
-        if (size >= 100 && size <= 10_000) {
+        if (size >= 100 && size <= 20_000) {
             maxBatchSize.set(size);
         }
     }
diff --git a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerQueryResultProcessor.java b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerQueryResultProcessor.java
index bce109de4..7efc5700e 100644
--- a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerQueryResultProcessor.java
+++ b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerQueryResultProcessor.java
@@ -128,7 +128,7 @@ public int processResult(ResultSet resultSet) {
 
             // DDL
             if (operationCode == RowMapper.DDL) {
-                LOGGER.debug("DDL: {}, REDO_SQL {}", logMessage, redo_sql);
+                LOGGER.debug("DDL: {}, REDO_SQL: {}", logMessage, redo_sql);
                 continue;
                 // todo parse, add to the collection.
             }
diff --git a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerStreamingChangeEventSource.java b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerStreamingChangeEventSource.java
index d3eedeeb2..4819a0f1a 100644
--- a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerStreamingChangeEventSource.java
+++ b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/LogMinerStreamingChangeEventSource.java
@@ -155,7 +155,7 @@ public void execute(ChangeEventSourceContext context) throws InterruptedExceptio
                                 transactionalBuffer.abandonLongTransactions(nextOldestScn);
                                 LOGGER.debug("After abandoning, offset before: {}, offset after:{}", offsetContext.getScn(), nextOldestScn);
                                 offsetContext.setScn(nextOldestScn);
-                                lastProcessedScn = transactionalBuffer.getLargestScn().equals(BigDecimal.ZERO) ? nextScn : transactionalBuffer.getLargestScn().longValue();
+                                updateStartScn();
                             });
 
                             LogMinerHelper.setRedoLogFilesForMining(connection, lastProcessedScn);
@@ -181,15 +181,15 @@ public void execute(ChangeEventSourceContext context) throws InterruptedExceptio
                         metronome.pause();
                     }
 
+                    updateStartScn();
+
                     // get largest scn from the last uncommitted transaction and set as last processed scn
                     LOGGER.trace("largest scn = {}", transactionalBuffer.getLargestScn());
 
-                    lastProcessedScn  = transactionalBuffer.getLargestScn().equals(BigDecimal.ZERO) ? nextScn : transactionalBuffer.getLargestScn().longValue();
-
                     // update SCN in offset context only if buffer is empty, otherwise we update offset in TransactionalBuffer
                     if (transactionalBuffer.isEmpty()) {
                         offsetContext.setScn(lastProcessedScn);
-                        transactionalBuffer.resetLargestScn();
+                        transactionalBuffer.resetLargestScn(null);
                     }
 
                     res.close();
@@ -217,6 +217,16 @@ public void execute(ChangeEventSourceContext context) throws InterruptedExceptio
         }
     }
 
+    private void updateStartScn() {
+        long startScn  = transactionalBuffer.getLargestScn().equals(BigDecimal.ZERO) ? nextScn : transactionalBuffer.getLargestScn().longValue();
+        if (startScn == lastProcessedScn) {
+            transactionalBuffer.resetLargestScn(nextScn);
+            lastProcessedScn  = nextScn;
+        } else {
+            lastProcessedScn = startScn;
+        }
+    }
+
     @Override
     public void commitOffset(Map<String, ?> offset) {
         // nothing to do
diff --git a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/TransactionalBuffer.java b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/TransactionalBuffer.java
index 0b29cb76e..7c2c22523 100644
--- a/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/TransactionalBuffer.java
+++ b/debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/logminer/TransactionalBuffer.java
@@ -82,15 +82,18 @@ public final class TransactionalBuffer {
      * @return largest last SCN in the buffer among all transactions
      */
     public BigDecimal getLargestScn() {
-        calculateLargestScn();
         return largestScn;
     }
 
     /**
-     * Reset Largest SCNs
+     * Reset Largest SCN
      */
-    public void resetLargestScn() {
-        largestScn = BigDecimal.ZERO;
+    public void resetLargestScn(Long value) {
+        if (value != null) {
+            largestScn = new BigDecimal(value);
+        } else {
+            largestScn = BigDecimal.ZERO;
+        }
     }
 
     /**
@@ -274,10 +277,11 @@ boolean rollback(String transactionId, String debugMessage) {
             metrics.ifPresent(m -> m.setActiveTransactions(transactions.size()));
             metrics.ifPresent(TransactionalBufferMetrics::incrementRolledBackTransactions);
             metrics.ifPresent(m -> m.addRolledBackTransactionId(transactionId));
+
+            transactions.remove(transactionId);
             return true;
         }
 
-        transactions.remove(transactionId);
         return false;
     }
 
diff --git a/debezium-connector-oracle/src/test/java/io/debezium/connector/oracle/logminer/TransactionalBufferTest.java b/debezium-connector-oracle/src/test/java/io/debezium/connector/oracle/logminer/TransactionalBufferTest.java
index ad385edc0..3bccfdc18 100644
--- a/debezium-connector-oracle/src/test/java/io/debezium/connector/oracle/logminer/TransactionalBufferTest.java
+++ b/debezium-connector-oracle/src/test/java/io/debezium/connector/oracle/logminer/TransactionalBufferTest.java
@@ -97,6 +97,8 @@ public void testIsEmptyWhenTransactionIsRolledBack() {
         assertThat(transactionalBuffer.isEmpty()).isEqualTo(true);
     }
 
+    // todo more tests
+
     @Test
     public void testCalculateSmallestScnWhenTransactionIsCommitted() throws InterruptedException {
         CountDownLatch commitLatch = new CountDownLatch(1);