[HUDI-4372] Enable matadata table by default for flink (#6066)

hudi-client/hudi-flink-client/src/main/java/org/apache/hudi/client/HoodieFlinkWriteClient.java

@@ -96,7 +96,7 @@ public class HoodieFlinkWriteClient<T extends HoodieRecordPayload> extends
   /**
    * Cached metadata writer for coordinator to reuse for each commit.
    */
-  private Option<HoodieBackedTableMetadataWriter> metadataWriterOption = Option.empty();
+  private HoodieBackedTableMetadataWriter metadataWriter;
 
   public HoodieFlinkWriteClient(HoodieEngineContext context, HoodieWriteConfig writeConfig) {
     super(context, writeConfig, FlinkUpgradeDowngradeHelper.getInstance());
@@ -264,10 +264,17 @@ public class HoodieFlinkWriteClient<T extends HoodieRecordPayload> extends
 
   @Override
   protected void writeTableMetadata(HoodieTable table, String instantTime, String actionType, HoodieCommitMetadata metadata) {
-    this.metadataWriterOption.ifPresent(w -> {
-      w.initTableMetadata(); // refresh the timeline
-      w.update(metadata, instantTime, getHoodieTable().isTableServiceAction(actionType));
-    });
+    if (this.metadataWriter == null) {
+      initMetadataWriter();
+    }
+    // refresh the timeline
+
+    // Note: the data meta client is not refreshed currently, some code path
+    // relies on the meta client for resolving the latest data schema,
+    // the schema expects to be immutable for SQL jobs but may be not for non-SQL
+    // jobs.
+    this.metadataWriter.initTableMetadata();
+    this.metadataWriter.update(metadata, instantTime, getHoodieTable().isTableServiceAction(actionType));
   }
 
   /**
@@ -275,9 +282,24 @@ public class HoodieFlinkWriteClient<T extends HoodieRecordPayload> extends
    * from the filesystem if it does not exist.
    */
   public void initMetadataWriter() {
-    HoodieBackedTableMetadataWriter metadataWriter = (HoodieBackedTableMetadataWriter) FlinkHoodieBackedTableMetadataWriter.create(
+    this.metadataWriter = (HoodieBackedTableMetadataWriter) FlinkHoodieBackedTableMetadataWriter.create(
         FlinkClientUtil.getHadoopConf(), this.config, HoodieFlinkEngineContext.DEFAULT);
-    this.metadataWriterOption = Option.of(metadataWriter);
+  }
+
+  /**
+   * Initialized the metadata table on start up, should only be called once on driver.
+   */
+  public void initMetadataTable() {
+    HoodieFlinkTable<?> table = getHoodieTable();
+    if (config.isMetadataTableEnabled()) {
+      // initialize the metadata table path
+      initMetadataWriter();
+      // clean the obsolete index stats
+      table.deleteMetadataIndexIfNecessary();
+    } else {
+      // delete the metadata table if it was enabled but is now disabled
+      table.maybeDeleteMetadataTable();
+    }
   }
 
   /**