fix 'Not a valid schema field: ts' error in HoodieFlinkCompactor, if precombine field is not ts

Author: jian.feng

hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/compact/HoodieFlinkCompactor.java

@@ -173,6 +173,8 @@ public AsyncCompactionService(FlinkCompactionConfig cfg, Configuration conf, Str
       // set table schema
       CompactionUtil.setAvroSchema(conf, metaClient);
 
+      CompactionUtil.setPreCombineField(conf, metaClient);
+
       // infer changelog mode
       CompactionUtil.inferChangelogMode(conf, metaClient);
 

hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/util/CompactionUtil.java

@@ -119,6 +119,20 @@ public static void setAvroSchema(HoodieWriteConfig writeConfig, HoodieTableMetaC
     writeConfig.setSchema(tableAvroSchema.toString());
   }
 
+  /**
+   * Sets up the preCombine field into the given configuration {@code conf}
+   * through reading from the hoodie table metadata.
+   *
+   * This value is non-null as compaction can only be performed on MOR tables.
+   * Of which, MOR tables will have non-null precombine fields.
+   *
+   * @param conf The configuration
+   */
+  public static void setPreCombineField(Configuration conf, HoodieTableMetaClient metaClient) {
+    String preCombineField = metaClient.getTableConfig().getPreCombineField();
+    conf.setString(FlinkOptions.PRECOMBINE_FIELD, preCombineField);
+  }
+
   /**
    * Infers the changelog mode based on the data file schema(including metadata fields).
    *