[Source-mongo] : Implement fixed chunk size (1million) (#37559)

Author: akashkulk

airbyte-integrations/connectors/source-mongodb-v2/metadata.yaml

@@ -8,7 +8,7 @@ data:
   connectorSubtype: database
   connectorType: source
   definitionId: b2e713cd-cc36-4c0a-b5bd-b47cb8a0561e
-  dockerImageTag: 1.3.7
+  dockerImageTag: 1.3.8
   dockerRepository: airbyte/source-mongodb-v2
   documentationUrl: https://docs.airbyte.com/integrations/sources/mongodb-v2
   githubIssueLabel: source-mongodb-v2

airbyte-integrations/connectors/source-mongodb-v2/src/main/java/io/airbyte/integrations/source/mongodb/InitialSnapshotHandler.java

@@ -31,6 +31,7 @@
 public class InitialSnapshotHandler {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(InitialSnapshotHandler.class);
+  private static final int DEFAULT_CHUNK_SIZE = 1_000_000;
 
   /**
    * For each given stream configured as incremental sync it will output an iterator that will
@@ -67,7 +68,7 @@ public List<AutoCloseableIterator<AirbyteMessage>> getIterators(
           final Optional<MongoDbStreamState> existingState =
               stateManager.getStreamState(airbyteStream.getStream().getName(), airbyteStream.getStream().getNamespace());
 
-          final var recordIterator = new MongoDbInitialLoadRecordIterator(collection, fields, existingState, isEnforceSchema);
+          final var recordIterator = new MongoDbInitialLoadRecordIterator(collection, fields, existingState, isEnforceSchema, DEFAULT_CHUNK_SIZE);
           final var stateIterator =
               new SourceStateIterator<>(recordIterator, airbyteStream, stateManager, new StateEmitFrequency(checkpointInterval,
                   MongoConstants.CHECKPOINT_DURATION));

airbyte-integrations/connectors/source-mongodb-v2/src/main/java/io/airbyte/integrations/source/mongodb/MongoDbInitialLoadRecordIterator.java

@@ -39,6 +39,8 @@ public class MongoDbInitialLoadRecordIterator extends AbstractIterator<Document>
   private final boolean isEnforceSchema;
   private final MongoCollection<Document> collection;
   private final Bson fields;
+  // Represents the number of rows to get with each query.
+  private final int chunkSize;
 
   private Optional<MongoDbStreamState> currentState;
   private MongoCursor<Document> currentIterator;
@@ -48,19 +50,22 @@ public class MongoDbInitialLoadRecordIterator extends AbstractIterator<Document>
   MongoDbInitialLoadRecordIterator(final MongoCollection<Document> collection,
                                    final Bson fields,
                                    final Optional<MongoDbStreamState> existingState,
-                                   final boolean isEnforceSchema) {
+                                   final boolean isEnforceSchema,
+                                   final int chunkSize) {
     this.collection = collection;
     this.fields = fields;
     this.currentState = existingState;
     this.isEnforceSchema = isEnforceSchema;
+    this.chunkSize = chunkSize;
     this.currentIterator = buildNewQueryIterator();
   }
 
   @Override
   protected Document computeNext() {
     if (shouldBuildNextQuery()) {
       try {
-        LOGGER.info("Finishing subquery number : {}", numSubqueries);
+        LOGGER.info("Finishing subquery number : {}, processing at id : {}", numSubqueries,
+            currentState.get() == null ? "starting null" : currentState.get().id());
         currentIterator.close();
         currentIterator = buildNewQueryIterator();
         numSubqueries++;
@@ -98,11 +103,13 @@ private MongoCursor<Document> buildNewQueryIterator() {
     return isEnforceSchema ? collection.find()
         .filter(filter)
         .projection(fields)
+        .limit(chunkSize)
         .sort(Sorts.ascending(MongoConstants.ID_FIELD))
         .allowDiskUse(true)
         .cursor()
         : collection.find()
             .filter(filter)
+            .limit(chunkSize)
             .sort(Sorts.ascending(MongoConstants.ID_FIELD))
             .allowDiskUse(true)
             .cursor();

airbyte-integrations/connectors/source-mongodb-v2/src/test/java/io/airbyte/integrations/source/mongodb/cdc/MongoDbCdcInitializerTest.java

@@ -14,6 +14,7 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyList;
 import static org.mockito.Mockito.doCallRealMethod;
 import static org.mockito.Mockito.doReturn;
@@ -153,6 +154,7 @@ void setUp() {
     when(mongoCollection.find()).thenReturn(findIterable);
     when(findIterable.filter(any())).thenReturn(findIterable);
     when(findIterable.projection(any())).thenReturn(findIterable);
+    when(findIterable.limit(anyInt())).thenReturn(findIterable);
     when(findIterable.sort(any())).thenReturn(findIterable);
     when(findIterable.cursor()).thenReturn(findCursor);
     when(findCursor.hasNext()).thenReturn(true);

docs/integrations/sources/mongodb-v2.md

@@ -221,9 +221,10 @@ For more information regarding configuration parameters, please see [MongoDb Doc
 
 | Version | Date       | Pull Request                                             | Subject                                                                                                   |
 |:--------|:-----------|:---------------------------------------------------------|:----------------------------------------------------------------------------------------------------------|
+| 1.3.8   | 2024-04-24 | [37559](https://github.com/airbytehq/airbyte/pull/37559) | Implement fixed-size chunking while performing initial load.                                              |
 | 1.3.7   | 2024-04-24 | [37557](https://github.com/airbytehq/airbyte/pull/37557) | Change bug in resume token validity check.                                                                |
-| 1.3.6   | 2024-04-24 | [37525](https://github.com/airbytehq/airbyte/pull/37525) | Internal refactor.                                                           |
-| 1.3.5   | 2024-04-22 | [37348](https://github.com/airbytehq/airbyte/pull/37348) | Do not send estimate trace if we do not have data.                                                           |
+| 1.3.6   | 2024-04-24 | [37525](https://github.com/airbytehq/airbyte/pull/37525) | Internal refactor.                                                                                        |
+| 1.3.5   | 2024-04-22 | [37348](https://github.com/airbytehq/airbyte/pull/37348) | Do not send estimate trace if we do not have data.                                                        |
 | 1.3.4   | 2024-04-16 | [37348](https://github.com/airbytehq/airbyte/pull/37348) | Populate null values in airbyte record messages.                                                          |
 | 1.3.3   | 2024-04-05 | [36872](https://github.com/airbytehq/airbyte/pull/36872) | Update to connector's metadat definition.                                                                 |
 | 1.3.2   | 2024-04-04 | [36845](https://github.com/airbytehq/airbyte/pull/36845) | Adopt Kotlin CDK.                                                                                         |