private MMVSource convertToSourceTable(String catalog, SourceTable sourceTable) {
    Table table = sourceTable.getTable();
    MTable mtbl = getMTable(catalog, table.getDbName(), table.getTableName(), false).mtbl;
    MMVSource source = new MMVSource();
    source.setTable(mtbl);
    source.setInsertedCount(sourceTable.getInsertedCount());
    source.setUpdatedCount(sourceTable.getUpdatedCount());
    source.setDeletedCount(sourceTable.getDeletedCount());
    return source;
  }
Converts a storage descriptor to a db-backed storage descriptor.  It points the
storage descriptor's column descriptor to the one passed as an argument,
so it does not create a new mcolumn descriptor object.
@param sd the storage descriptor to wrap in a db-backed object
@param mcd the db-backed column descriptor
@return the db-backed storage descriptor object
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java