diff --git a/document-store/src/main/java/org/hypertrace/core/documentstore/mongo/MongoCollection.java b/document-store/src/main/java/org/hypertrace/core/documentstore/mongo/MongoCollection.java
index 451cb72a..18dd1c80 100644
--- a/document-store/src/main/java/org/hypertrace/core/documentstore/mongo/MongoCollection.java
+++ b/document-store/src/main/java/org/hypertrace/core/documentstore/mongo/MongoCollection.java
@@ -104,19 +104,14 @@ private boolean allBulkWriteErrorsAreDueToDuplicateKey(MongoBulkWriteException b
    */
   @Override
   public boolean upsert(Key key, Document document) throws IOException {
-    try {
-      UpdateOptions options = new UpdateOptions().upsert(true);
-      UpdateResult writeResult =
-          collection.updateOne(this.selectionCriteriaForKey(key), this.prepareUpsert(key, document), options);
-      if (LOGGER.isDebugEnabled()) {
-        LOGGER.debug("Write result: " + writeResult.toString());
-      }
-
-      return writeResult.getModifiedCount() > 0;
-    } catch (IOException e) {
-      LOGGER.error("Exception upserting document. key: {} content:{}", key, document, e);
-      throw e;
+    UpdateOptions options = new UpdateOptions().upsert(true);
+    UpdateResult writeResult =
+        collection.updateOne(selectionCriteriaForKey(key), prepareUpsert(key, document), options);
+    if (LOGGER.isDebugEnabled()) {
+      LOGGER.debug("Write result: {}", writeResult);
     }
+
+    return writeResult.getModifiedCount() > 0;
   }
 
   /**
@@ -126,22 +121,22 @@ public boolean upsert(Key key, Document document) throws IOException {
   @Override
   public Document upsertAndReturn(Key key, Document document) throws IOException {
     BasicDBObject upsertResult = Failsafe.with(upsertRetryPolicy).get(() -> collection.findOneAndUpdate(
-        this.selectionCriteriaForKey(key),
-        this.prepareUpsert(key, document),
+        selectionCriteriaForKey(key),
+        prepareUpsert(key, document),
         new FindOneAndUpdateOptions().upsert(true).returnDocument(ReturnDocument.AFTER)));
     if (upsertResult == null) {
       throw new IOException("Could not upsert the document with key: " + key);
     }
 
-    return this.dbObjectToDocument(upsertResult);
+    return dbObjectToDocument(upsertResult);
   }
 
-  private BasicDBObject prepareUpsert(Key key, Document document) throws JsonProcessingException {
+  private static BasicDBObject prepareUpsert(Key key, Document document) throws JsonProcessingException {
     String jsonString = document.toJson();
     JsonNode jsonNode = MAPPER.readTree(jsonString);
 
     // escape "." and "$" in field names since Mongo DB does not like them
-    JsonNode sanitizedJsonNode = recursiveClone(jsonNode, this::encodeKey);
+    JsonNode sanitizedJsonNode = recursiveClone(jsonNode, MongoCollection::encodeKey);
     BasicDBObject setObject = BasicDBObject.parse(MAPPER.writeValueAsString(sanitizedJsonNode));
     long now = System.currentTimeMillis();
     setObject.put(ID_KEY, key.toString());
@@ -161,7 +156,7 @@ public boolean updateSubDoc(Key key, String subDocPath, Document subDocument) {
       JsonNode jsonNode = MAPPER.readTree(jsonString);
 
       // escape "." and "$" in field names since Mongo DB does not like them
-      JsonNode sanitizedJsonNode = recursiveClone(jsonNode, this::encodeKey);
+      JsonNode sanitizedJsonNode = recursiveClone(jsonNode, MongoCollection::encodeKey);
       BasicDBObject dbObject =
           new BasicDBObject(
               subDocPath, BasicDBObject.parse(MAPPER.writeValueAsString(sanitizedJsonNode)));
@@ -171,7 +166,7 @@ public boolean updateSubDoc(Key key, String subDocPath, Document subDocument) {
       UpdateResult writeResult = collection.updateOne(selectionCriteriaForKey(key), setObject,
           new UpdateOptions());
       if (LOGGER.isDebugEnabled()) {
-        LOGGER.debug("Write result: " + writeResult.toString());
+        LOGGER.debug("Write result: {}", writeResult);
       }
       // TODO:look into the writeResult to ensure it was successful. Was not easy to find this from
       // docs.
@@ -182,7 +177,7 @@ public boolean updateSubDoc(Key key, String subDocPath, Document subDocument) {
     }
   }
 
-  private JsonNode recursiveClone(JsonNode src, Function<String, String> function) {
+  private static JsonNode recursiveClone(JsonNode src, Function<String, String> function) {
     if (!src.isObject()) {
       return src;
     }
@@ -202,11 +197,11 @@ private JsonNode recursiveClone(JsonNode src, Function<String, String> function)
     return tgt;
   }
 
-  private String encodeKey(String key) {
+  private static String encodeKey(String key) {
     return key.replace("\\", "\\\\").replace("$", "\\u0024").replace(".", "\\u002e");
   }
 
-  private String decodeKey(String key) {
+  private static String decodeKey(String key) {
     return key.replace("\\u002e", ".").replace("\\u0024", "$").replace("\\\\", "\\");
   }
 
@@ -255,14 +250,14 @@ public boolean hasNext() {
 
       @Override
       public Document next() {
-        return MongoCollection.this.dbObjectToDocument(mongoCursor.next());
+        return dbObjectToDocument(mongoCursor.next());
       }
     };
   }
 
   @Override
   public boolean delete(Key key) {
-    DeleteResult deleteResult = collection.deleteOne(this.selectionCriteriaForKey(key));
+    DeleteResult deleteResult = collection.deleteOne(selectionCriteriaForKey(key));
     return deleteResult.getDeletedCount() > 0;
   }
 
@@ -270,9 +265,9 @@ public boolean delete(Key key) {
   public boolean deleteSubDoc(Key key, String subDocPath) {
     BasicDBObject unsetObject = new BasicDBObject("$unset", new BasicDBObject(subDocPath, ""));
 
-    UpdateResult updateResult = collection.updateOne(this.selectionCriteriaForKey(key), unsetObject);
+    UpdateResult updateResult = collection.updateOne(selectionCriteriaForKey(key), unsetObject);
     if (LOGGER.isDebugEnabled()) {
-      LOGGER.debug("Write result: " + updateResult.toString());
+      LOGGER.debug("Update result: {}", updateResult);
     }
 
     return updateResult.getModifiedCount() > 0;
@@ -286,7 +281,7 @@ public boolean deleteAll() {
     return true;
   }
 
-  private void parseOrderByQuery(List<OrderBy> orderBys, Map<String, Object> orderbyMap) {
+  private static void parseOrderByQuery(List<OrderBy> orderBys, Map<String, Object> orderbyMap) {
     for (OrderBy orderBy : orderBys) {
       orderbyMap.put(orderBy.getField(), (orderBy.isAsc() ? 1 : -1));
     }
@@ -388,7 +383,7 @@ public long total(Query query) {
   public boolean bulkUpsert(Map<Key, Document> documents) {
     try {
       BulkWriteResult result = bulkUpsertImpl(documents);
-      LOGGER.debug(result.toString());
+      LOGGER.debug("BulkWriteResult: {}", result);
       return true;
     } catch (IOException | MongoServerException e) {
       LOGGER.error("Error during bulk upsert for documents:{}", documents, e);
@@ -402,7 +397,7 @@ private BulkWriteResult bulkUpsertImpl(Map<Key, Document> documents) throws Json
       Key key = entry.getKey();
       // insert or overwrite
       bulkCollection.add(new UpdateOneModel<>(
-          this.selectionCriteriaForKey(key),
+          selectionCriteriaForKey(key),
           prepareUpsert(key, entry.getValue()),
           new UpdateOptions().upsert(true)));
     }
@@ -420,7 +415,7 @@ public Iterator<Document> bulkUpsertAndReturnOlderDocuments(Map<Key, Document> d
 
       // Now go ahead and do the bulk upsert.
       BulkWriteResult result = bulkUpsertImpl(documents);
-      LOGGER.debug(result.toString());
+      LOGGER.debug("BulkWriteResult: {}", result);
 
       return new Iterator<>() {
         @Override
@@ -430,12 +425,11 @@ public boolean hasNext() {
 
         @Override
         public Document next() {
-          return MongoCollection.this.dbObjectToDocument(mongoCursor.next());
+          return dbObjectToDocument(mongoCursor.next());
         }
       };
     } catch (JsonProcessingException e) {
-      LOGGER.error("Error during bulk upsert for documents:{}", documents, e);
-      throw new IOException("Error during bulk upsert.");
+      throw new IOException("Error during bulk upsert.", e);
     }
   }
 
@@ -444,16 +438,16 @@ public void drop() {
     collection.drop();
   }
 
-  private BasicDBObject selectionCriteriaForKey(Key key) {
+  private static BasicDBObject selectionCriteriaForKey(Key key) {
     return new BasicDBObject(ID_KEY, key.toString());
   }
 
-  private BasicDBObject selectionCriteriaForKeys(Set<Key> keys) {
+  private static BasicDBObject selectionCriteriaForKeys(Set<Key> keys) {
     return new BasicDBObject(Map.of(ID_KEY, new BasicDBObject("$in",
         keys.stream().map(Key::toString).collect(Collectors.toList()))));
   }
 
-  private Document dbObjectToDocument(BasicDBObject dbObject) {
+  private static Document dbObjectToDocument(BasicDBObject dbObject) {
     try {
       // Hack: Remove the _id field since it's an unrecognized field for Proto layer.
       // TODO: We should rather use separate DAO classes instead of using the
@@ -464,7 +458,7 @@ private Document dbObjectToDocument(BasicDBObject dbObject) {
           JsonWriterSettings.builder().outputMode(JsonMode.RELAXED).build();
       jsonString = dbObject.toJson(relaxed);
       JsonNode jsonNode = MAPPER.readTree(jsonString);
-      JsonNode decodedJsonNode = recursiveClone(jsonNode, this::decodeKey);
+      JsonNode decodedJsonNode = recursiveClone(jsonNode, MongoCollection::decodeKey);
       return new JSONDocument(decodedJsonNode);
     } catch (IOException e) {
       // throwing exception is not very useful here.