1 files changed, 134 insertions, 0 deletions

diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index e33231f7be8..23c0fb9379b 100644
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -3696,3 +3696,137 @@ ExecBuildGroupingEqual(TupleDesc ldesc, TupleDesc rdesc,
 
 	return state;
 }
+
+/*
+ * Build equality expression that can be evaluated using ExecQual(), returning
+ * true if the expression context's inner/outer tuples are equal.  Datums in
+ * the inner/outer slots are assumed to be in the same order and quantity as
+ * the 'eqfunctions' parameter.  NULLs are treated as equal.
+ *
+ * desc: tuple descriptor of the to-be-compared tuples
+ * lops: the slot ops for the inner tuple slots
+ * rops: the slot ops for the outer tuple slots
+ * eqFunctions: array of function oids of the equality functions to use
+ * this must be the same length as the 'param_exprs' list.
+ * collations: collation Oids to use for equality comparison. Must be the
+ * same length as the 'param_exprs' list.
+ * parent: parent executor node
+ */
+ExprState *
+ExecBuildParamSetEqual(TupleDesc desc,
+					   const TupleTableSlotOps *lops,
+					   const TupleTableSlotOps *rops,
+					   const Oid *eqfunctions,
+					   const Oid *collations,
+					   const List *param_exprs,
+					   PlanState *parent)
+{
+	ExprState  *state = makeNode(ExprState);
+	ExprEvalStep scratch = {0};
+	int			maxatt = list_length(param_exprs);
+	List	   *adjust_jumps = NIL;
+	ListCell   *lc;
+
+	state->expr = NULL;
+	state->flags = EEO_FLAG_IS_QUAL;
+	state->parent = parent;
+
+	scratch.resvalue = &state->resvalue;
+	scratch.resnull = &state->resnull;
+
+	/* push deform steps */
+	scratch.opcode = EEOP_INNER_FETCHSOME;
+	scratch.d.fetch.last_var = maxatt;
+	scratch.d.fetch.fixed = false;
+	scratch.d.fetch.known_desc = desc;
+	scratch.d.fetch.kind = lops;
+	if (ExecComputeSlotInfo(state, &scratch))
+		ExprEvalPushStep(state, &scratch);
+
+	scratch.opcode = EEOP_OUTER_FETCHSOME;
+	scratch.d.fetch.last_var = maxatt;
+	scratch.d.fetch.fixed = false;
+	scratch.d.fetch.known_desc = desc;
+	scratch.d.fetch.kind = rops;
+	if (ExecComputeSlotInfo(state, &scratch))
+		ExprEvalPushStep(state, &scratch);
+
+	for (int attno = 0; attno < maxatt; attno++)
+	{
+		Form_pg_attribute att = TupleDescAttr(desc, attno);
+		Oid			foid = eqfunctions[attno];
+		Oid			collid = collations[attno];
+		FmgrInfo   *finfo;
+		FunctionCallInfo fcinfo;
+		AclResult	aclresult;
+
+		/* Check permission to call function */
+		aclresult = pg_proc_aclcheck(foid, GetUserId(), ACL_EXECUTE);
+		if (aclresult != ACLCHECK_OK)
+			aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(foid));
+
+		InvokeFunctionExecuteHook(foid);
+
+		/* Set up the primary fmgr lookup information */
+		finfo = palloc0(sizeof(FmgrInfo));
+		fcinfo = palloc0(SizeForFunctionCallInfo(2));
+		fmgr_info(foid, finfo);
+		fmgr_info_set_expr(NULL, finfo);
+		InitFunctionCallInfoData(*fcinfo, finfo, 2,
+								 collid, NULL, NULL);
+
+		/* left arg */
+		scratch.opcode = EEOP_INNER_VAR;
+		scratch.d.var.attnum = attno;
+		scratch.d.var.vartype = att->atttypid;
+		scratch.resvalue = &fcinfo->args[0].value;
+		scratch.resnull = &fcinfo->args[0].isnull;
+		ExprEvalPushStep(state, &scratch);
+
+		/* right arg */
+		scratch.opcode = EEOP_OUTER_VAR;
+		scratch.d.var.attnum = attno;
+		scratch.d.var.vartype = att->atttypid;
+		scratch.resvalue = &fcinfo->args[1].value;
+		scratch.resnull = &fcinfo->args[1].isnull;
+		ExprEvalPushStep(state, &scratch);
+
+		/* evaluate distinctness */
+		scratch.opcode = EEOP_NOT_DISTINCT;
+		scratch.d.func.finfo = finfo;
+		scratch.d.func.fcinfo_data = fcinfo;
+		scratch.d.func.fn_addr = finfo->fn_addr;
+		scratch.d.func.nargs = 2;
+		scratch.resvalue = &state->resvalue;
+		scratch.resnull = &state->resnull;
+		ExprEvalPushStep(state, &scratch);
+
+		/* then emit EEOP_QUAL to detect if result is false (or null) */
+		scratch.opcode = EEOP_QUAL;
+		scratch.d.qualexpr.jumpdone = -1;
+		scratch.resvalue = &state->resvalue;
+		scratch.resnull = &state->resnull;
+		ExprEvalPushStep(state, &scratch);
+		adjust_jumps = lappend_int(adjust_jumps,
+								   state->steps_len - 1);
+	}
+
+	/* adjust jump targets */
+	foreach(lc, adjust_jumps)
+	{
+		ExprEvalStep *as = &state->steps[lfirst_int(lc)];
+
+		Assert(as->opcode == EEOP_QUAL);
+		Assert(as->d.qualexpr.jumpdone == -1);
+		as->d.qualexpr.jumpdone = state->steps_len;
+	}
+
+	scratch.resvalue = NULL;
+	scratch.resnull = NULL;
+	scratch.opcode = EEOP_DONE;
+	ExprEvalPushStep(state, &scratch);
+
+	ExecReadyExpr(state);
+
+	return state;
+}