Function PushdownRuntimeFilter

src/backend/executor/nodeHash.c:4151–4211

* Convert AttrFilter to ScanKeyData and send these runtime filters to the * target node(seqscan). */

 * target node(seqscan).
 */
void
PushdownRuntimeFilter(HashState *node)
{
	ListCell	*lc;
	List		*scankeys;
	ScanKey		sk;
	AttrFilter	*attr_filter;

	foreach (lc, node->filters)
	{
		scankeys = NIL;

		attr_filter = lfirst(lc);
		if (attr_filter->empty ||
			(!IsA(attr_filter->target, SeqScanState) &&
			 !IsA(attr_filter->target, DynamicSeqScanState)))
			continue;

		/* bloom filter */
		sk = (ScanKey)palloc0(sizeof(ScanKeyData));
		sk->sk_flags    = SK_BLOOM_FILTER;
		sk->sk_attno    = attr_filter->lattno;
		sk->sk_subtype  = INT8OID;
		sk->sk_argument = PointerGetDatum(attr_filter->blm_filter);
		scankeys = lappend(scankeys, sk);

		/* range filter */
		sk = (ScanKey)palloc0(sizeof(ScanKeyData));
		sk->sk_flags    = 0;
		sk->sk_attno    = attr_filter->lattno;
		sk->sk_strategy = BTGreaterEqualStrategyNumber;
		sk->sk_subtype  = INT8OID;
		sk->sk_argument = attr_filter->min;
		scankeys = lappend(scankeys, sk);

		sk = (ScanKey)palloc0(sizeof(ScanKeyData));
		sk->sk_flags    = 0;
		sk->sk_attno    = attr_filter->lattno;
		sk->sk_strategy = BTLessEqualStrategyNumber;
		sk->sk_subtype  = INT8OID;
		sk->sk_argument = attr_filter->max;
		scankeys = lappend(scankeys, sk);

		/* append new runtime filters to target node */
		if (IsA(attr_filter->target, SeqScanState))
		{
			SeqScanState *sss = castNode(SeqScanState, attr_filter->target);
			sss->filters = list_concat(sss->filters, scankeys);
		}
		else if (IsA(attr_filter->target, DynamicSeqScanState))
		{
			DynamicSeqScanState *dsss = castNode(DynamicSeqScanState, attr_filter->target);
			dsss->filters = list_concat(dsss->filters, scankeys);
		}
		else
		{
			/* never reach here */
			pg_unreachable();