/*
* InitScanStateInternal
* Initialize ScanState common variables for various Scan node.
*/
void
InitScanStateInternal(ScanState *scanState, Plan *plan, EState *estate,
int eflags, bool initCurrentRelation)
{
Assert(IsA(plan, SeqScan) ||
IsA(plan, AppendOnlyScan) ||
IsA(plan, ParquetScan) ||
IsA(plan, TableScan) ||
IsA(plan, DynamicTableScan) ||
IsA(plan, BitmapTableScan));
PlanState *planState = &scanState->ps;
planState->plan = plan;
planState->state = estate;
/* Create expression evaluation context */
ExecAssignExprContext(estate, planState);
/* Initialize tuple table slot */
ExecInitResultTupleSlot(estate, planState);
ExecInitScanTupleSlot(estate, scanState);
/*
* For dynamic table scan, We do not initialize expression states; instead
* we wait until the first partition, and initialize the expression state
* at that time. Also, for dynamic table scan, we do not need to open the
* parent partition relation.
*/
if (initCurrentRelation)
{
InitScanStateRelationDetails(scanState, plan, estate);
}
/* Initialize result tuple type. */
ExecAssignResultTypeFromTL(planState);
/*
* If eflag contains EXEC_FLAG_REWIND or EXEC_FLAG_BACKWARD or EXEC_FLAG_MARK,
* then this node is not eager free safe.
*/
scanState->ps.delayEagerFree =
((eflags & (EXEC_FLAG_REWIND | EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)) != 0);
/* Currently, only SeqScan supports Mark/Restore. */
AssertImply((eflags & EXEC_FLAG_MARK) != 0, IsA(plan, SeqScan));
}
/*
* DynamicScan_InitSingleRelation
* Prepares a single relation for scanning by calling various
* helper methods to open relation, initialize expressions etc.
*
* Note: this is for the non-partitioned relations.
*
* Returns true upon success.
*/
static bool
DynamicScan_InitSingleRelation(ScanState *scanState, PartitionInitMethod *partitionInitMethod, PartitionReScanMethod *partitionReScanMethod)
{
Assert(!isDynamicScan((Scan *)scanState->ps.plan));
if (NULL == scanState->ss_currentRelation)
{
/* Open the relation and initalize the expressions (targetlist, qual etc.) */
InitScanStateRelationDetails(scanState, scanState->ps.plan, scanState->ps.state);
partitionInitMethod(scanState, NULL /* No dropped column mapping */);
}
else
{
Insist(scanState->scan_state == SCAN_RESCAN);
partitionReScanMethod(scanState);
}
return true;
}
