Github user linwen commented on a diff in the pull request:
https://github.com/apache/incubator-hawq/pull/1350#discussion_r178484042
--- Diff: contrib/vexecutor/parquet_reader.c ---
@@ -0,0 +1,194 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+#include "parquet_reader.h"
+
+#include "executor/executor.h"
+#include "tuplebatch.h"
+#include "vcheck.h"
+
+extern bool getNextRowGroup(ParquetScanDesc scan);
+static int
+ParquetRowGroupReader_ScanNextTupleBatch(
+ TupleDesc tupDesc,
+ ParquetRowGroupReader *rowGroupReader,
+ int
*hawqAttrToParquetColNum,
+ bool *projs,
+ TupleTableSlot *slot);
+
+static void
+parquet_vgetnext(ParquetScanDesc scan, ScanDirection direction,
TupleTableSlot *slot);
+
+TupleTableSlot *
+ParquetVScanNext(ScanState *scanState)
+{
+ Assert(IsA(scanState, TableScanState) || IsA(scanState,
DynamicTableScanState));
+ ParquetScanState *node = (ParquetScanState *)scanState;
+ Assert(node->opaque != NULL && node->opaque->scandesc != NULL);
+
+ parquet_vgetnext(node->opaque->scandesc,
node->ss.ps.state->es_direction, node->ss.ss_ScanTupleSlot);
+ return node->ss.ss_ScanTupleSlot;
+}
+
+static void
+parquet_vgetnext(ParquetScanDesc scan, ScanDirection direction,
TupleTableSlot *slot)
+{
+
+ //AOTupleId aoTupleId;
+ Assert(ScanDirectionIsForward(direction));
+
+ for(;;)
+ {
+ if(scan->bufferDone)
+ {
+ /*
+ * Get the next row group. We call this function until
we
+ * successfully get a block to process, or finished
reading
+ * all the data (all 'segment' files) for this relation.
+ */
+ while(!getNextRowGroup(scan))
+ {
+ /* have we read all this relation's data. done!
*/
+ if(scan->pqs_done_all_splits)
+ {
+ ExecClearTuple(slot);
+ return /*NULL*/;
+ }
+ }
+ scan->bufferDone = false;
+ }
+
+ int row_num = ParquetRowGroupReader_ScanNextTupleBatch(
+
scan->pqs_tupDesc,
+
&scan->rowGroupReader,
+
scan->hawqAttrToParquetColChunks,
+ scan->proj,
+ slot);
+ if(row_num > 0)
+ return;
+
+ /* no more items in the row group, get new buffer */
+ scan->bufferDone = true;
+ }
+}
+
+/*
+ * Get next tuple batch from current row group into slot.
+ *
+ * Return false if current row group has no tuple left, true otherwise.
--- End diff --
According the comments, this function returns true or false, but at last it
returns a number of rows. If the function returns a number, it should not
return false when it finish scan row group, use "0" instead, since there is no
rows. If this function return a bool, it should not return a number.
---
