Parallel query, sequence scan.

src/gausskernel/runtime/executor/execAmi.cpp

@@ -26,7 +26,7 @@
 #include "executor/nodeExtensible.h"
 #include "executor/nodeForeignscan.h"
 #include "executor/nodeFunctionscan.h"
-#include "executor/nodeGroup.h"
+#include "executor/nodeGather.h"
 #include "executor/nodeGroup.h"
 #include "executor/nodeHash.h"
 #include "executor/nodeHashjoin.h"
@@ -131,6 +131,10 @@ void ExecReScanByType(PlanState* node)
             ExecReScanSeqScan((SeqScanState*)node);
             break;
 
+        case T_GatherState:
+            ExecReScanGather((GatherState*)node);
+            break;
+
         case T_IndexScanState:
             ExecReScanIndexScan((IndexScanState*)node);
             break;
@@ -492,8 +496,19 @@ bool ExecSupportsMarkRestore(NodeTag plantype)
  */
 bool ExecSupportsBackwardScan(Plan* node)
 {
-    if (node == NULL)
+    if (node == NULL) {
         return false;
+    }
+
+    /*
+     * Parallel-aware nodes return a subset of the tuples in each worker,
+     * and in general we can't expect to have enough bookkeeping state to
+     * know which ones we returned in this worker as opposed to some other
+     * worker.
+     */
+    if (node->parallel_aware) {
+        return false;
+    }
 
     switch (nodeTag(node)) {
         case T_BaseResult:
@@ -527,6 +542,9 @@ bool ExecSupportsBackwardScan(Plan* node)
         case T_CteScan:
             return target_list_supports_backward_scan(node->targetlist);
 
+        case T_Gather:
+            return false;
+
         case T_IndexScan:
             return index_supports_backward_scan(((IndexScan*)node)->indexid) &&
                    target_list_supports_backward_scan(node->targetlist);