Function ExecInitDynamicSeqScan

src/backend/executor/nodeDynamicSeqscan.c:41–103

static void CleanupOnePartition(DynamicSeqScanState *node);

DynamicSeqScanState *
ExecInitDynamicSeqScan(DynamicSeqScan *node, EState *estate, int eflags)
{
	DynamicSeqScanState *state;
	Oid			reloid;
	ListCell *lc;
	int i;

	Assert((eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)) == 0);

	state = makeNode(DynamicSeqScanState);
	state->eflags = eflags;
	state->ss.ps.plan = (Plan *) node;
	state->ss.ps.state = estate;
	state->ss.ps.ExecProcNode = ExecDynamicSeqScan;
	state->did_pruning = false;
	state->scan_state = SCAN_INIT;

	/* Initialize child expressions. This is needed to find subplans. */
	state->ss.ps.qual =
		ExecInitQual(node->seqscan.plan.qual, (PlanState *) state);

	Relation scanRel = ExecOpenScanRelation(estate, node->seqscan.scanrelid, eflags);
	ExecInitScanTupleSlot(estate, &state->ss, RelationGetDescr(scanRel), table_slot_callbacks(scanRel));

	/* Dynamic table/index/bitmap scan can't tell the ops of tupleslot */
	state->ss.ps.scanopsfixed = false;
	state->ss.ps.scanopsset = true;

	/* Initialize result tuple type. */
	ExecInitResultTypeTL(&state->ss.ps);
	ExecAssignScanProjectionInfo(&state->ss);

	state->ss.ps.resultopsfixed = false;
	state->ss.ps.resultopsset = true;

	state->nOids = list_length(node->partOids);
	state->partOids = palloc(sizeof(Oid) * state->nOids);
	foreach_with_count(lc, node->partOids, i)
		state->partOids[i] = lfirst_oid(lc);
	state->whichPart = -1;

	reloid = exec_rt_fetch(node->seqscan.scanrelid, estate)->relid;
	Assert(OidIsValid(reloid));

	/* lastRelOid is used to remap varattno for heterogeneous partitions */
	state->lastRelOid = reloid;

	state->scanrelid = node->seqscan.scanrelid;

	state->as_prune_state = NULL;

	/*
	 * This context will be reset per-partition to free up per-partition
	 * qual and targetlist allocations
	 */
	state->partitionMemoryContext = AllocSetContextCreate(CurrentMemoryContext,
									 "DynamicSeqScanPerPartition",