diff --git a/pkg/bench/ddl_analysis/orm_queries_bench_test.go b/pkg/bench/ddl_analysis/orm_queries_bench_test.go
index f7e2730a4163..2de13126ebac 100644
--- a/pkg/bench/ddl_analysis/orm_queries_bench_test.go
+++ b/pkg/bench/ddl_analysis/orm_queries_bench_test.go
@@ -80,6 +80,61 @@ WHERE (
     ) AND (n.nspname NOT IN ('pg_catalog', 'pg_toast'))
 ) AND pg_table_is_visible(c.oid)`,
 		},
+
+		{
+			name: "activerecord type introspection query",
+			stmt: `SELECT
+  t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype, t.typtype, t.typbasetype
+FROM
+  pg_type AS t LEFT JOIN pg_range AS r ON oid = rngtypid
+WHERE
+  t.typname
+  IN (
+      'int2',
+      'int4',
+      'int8',
+      'oid',
+      'float4',
+      'float8',
+      'text',
+      'varchar',
+      'char',
+      'name',
+      'bpchar',
+      'bool',
+      'bit',
+      'varbit',
+      'timestamptz',
+      'date',
+      'money',
+      'bytea',
+      'point',
+      'hstore',
+      'json',
+      'jsonb',
+      'cidr',
+      'inet',
+      'uuid',
+      'xml',
+      'tsvector',
+      'macaddr',
+      'citext',
+      'ltree',
+      'line',
+      'lseg',
+      'box',
+      'path',
+      'polygon',
+      'circle',
+      'interval',
+      'time',
+      'timestamp',
+      'numeric'
+    )
+  OR t.typtype IN ('r', 'e', 'd')
+  OR t.typinput = 'array_in(cstring,oid,integer)'::REGPROCEDURE
+  OR t.typelem != 0`,
+		},
 	}
 
 	RunRoundTripBenchmark(b, tests)
diff --git a/pkg/bench/ddl_analysis/testdata/benchmark_expectations b/pkg/bench/ddl_analysis/testdata/benchmark_expectations
index c50e956e4008..130525f45dd7 100644
--- a/pkg/bench/ddl_analysis/testdata/benchmark_expectations
+++ b/pkg/bench/ddl_analysis/testdata/benchmark_expectations
@@ -71,3 +71,4 @@ min	max	benchmark
 2	2	ORMQueries/django_table_introspection_1_table
 2	2	ORMQueries/django_table_introspection_4_tables
 2	2	ORMQueries/django_table_introspection_8_tables
+4   4   ORMQueries/activerecord_type_introspection_query
diff --git a/pkg/sql/logictest/testdata/logic_test/pg_catalog b/pkg/sql/logictest/testdata/logic_test/pg_catalog
index a7ef83e8dc2b..17ca86f88898 100644
--- a/pkg/sql/logictest/testdata/logic_test/pg_catalog
+++ b/pkg/sql/logictest/testdata/logic_test/pg_catalog
@@ -2761,9 +2761,6 @@ WHERE n.nspname = 'public'
 query error cannot access virtual schema in anonymous database
 SELECT count(*) FROM pg_catalog.pg_depend
 
-query error cannot access virtual schema in anonymous database
-select 'upper'::REGPROC;
-
 statement ok
 SET DATABASE = test
 
diff --git a/pkg/sql/pg_catalog.go b/pkg/sql/pg_catalog.go
index bd7cb3206e9e..5277eecee099 100644
--- a/pkg/sql/pg_catalog.go
+++ b/pkg/sql/pg_catalog.go
@@ -4158,6 +4158,24 @@ https://www.postgresql.org/docs/9.6/catalog-pg-aggregate.html`,
 	},
 }
 
+// Populate the oid-to-builtin-function map. We have to do this operation here,
+// rather than in the SQL builtins package, because the oidHasher can't live
+// there.
+func init() {
+	h := makeOidHasher()
+	tree.OidToBuiltinName = make(map[oid.Oid]string, len(tree.FunDefs))
+	for name, def := range tree.FunDefs {
+		for _, o := range def.Definition {
+			if overload, ok := o.(*tree.Overload); ok {
+				builtinOid := h.BuiltinOid(name, overload)
+				id := oid.Oid(builtinOid.DInt)
+				tree.OidToBuiltinName[id] = name
+				overload.Oid = id
+			}
+		}
+	}
+}
+
 // oidHasher provides a consistent hashing mechanism for object identifiers in
 // pg_catalog tables, allowing for reliable joins across tables.
 //
diff --git a/pkg/sql/sem/tree/casts.go b/pkg/sql/sem/tree/casts.go
index bccbb9bac10f..406f0c57190d 100644
--- a/pkg/sql/sem/tree/casts.go
+++ b/pkg/sql/sem/tree/casts.go
@@ -1271,43 +1271,13 @@ func performCastWithoutPrecisionTruncation(ctx *EvalContext, d Datum, t *types.T
 	case types.OidFamily:
 		switch v := d.(type) {
 		case *DOid:
-			switch t.Oid() {
-			case oid.T_oid:
-				return &DOid{semanticType: t, DInt: v.DInt}, nil
-			case oid.T_regtype:
-				// Mapping an oid to a regtype is easy: we have a hardcoded map.
-				typ, ok := types.OidToType[oid.Oid(v.DInt)]
-				ret := &DOid{semanticType: t, DInt: v.DInt}
-				if !ok {
-					return ret, nil
-				}
-				ret.name = typ.PGName()
-				return ret, nil
-			default:
-				oid, err := queryOid(ctx, t, v)
-				if err != nil {
-					oid = NewDOid(v.DInt)
-					oid.semanticType = t
-				}
-				return oid, nil
-			}
+			return performIntToOidCast(ctx, t, v.DInt)
 		case *DInt:
 			// OIDs are always unsigned 32-bit integers. Some languages, like Java,
 			// store OIDs as signed 32-bit integers, so we implement the cast
 			// by converting to a uint32 first. This matches Postgres behavior.
 			i := DInt(uint32(*v))
-			switch t.Oid() {
-			case oid.T_oid:
-				return &DOid{semanticType: t, DInt: i}, nil
-			default:
-				tmpOid := NewDOid(i)
-				oid, err := queryOid(ctx, t, tmpOid)
-				if err != nil {
-					oid = tmpOid
-					oid.semanticType = t
-				}
-				return oid, nil
-			}
+			return performIntToOidCast(ctx, t, i)
 		case *DString:
 			return ParseDOid(ctx, string(*v), t)
 		}
@@ -1316,3 +1286,39 @@ func performCastWithoutPrecisionTruncation(ctx *EvalContext, d Datum, t *types.T
 	return nil, pgerror.Newf(
 		pgcode.CannotCoerce, "invalid cast: %s -> %s", d.ResolvedType(), t)
 }
+
+// performIntToOidCast casts the input integer to the OID type given by the
+// input types.T.
+func performIntToOidCast(ctx *EvalContext, t *types.T, v DInt) (Datum, error) {
+	switch t.Oid() {
+	case oid.T_oid:
+		return &DOid{semanticType: t, DInt: v}, nil
+	case oid.T_regtype:
+		// Mapping an oid to a regtype is easy: we have a hardcoded map.
+		typ, ok := types.OidToType[oid.Oid(v)]
+		ret := &DOid{semanticType: t, DInt: v}
+		if !ok {
+			return ret, nil
+		}
+		ret.name = typ.PGName()
+		return ret, nil
+
+	case oid.T_regproc, oid.T_regprocedure:
+		// Mapping an oid to a regproc is easy: we have a hardcoded map.
+		name, ok := OidToBuiltinName[oid.Oid(v)]
+		ret := &DOid{semanticType: t, DInt: v}
+		if !ok {
+			return ret, nil
+		}
+		ret.name = name
+		return ret, nil
+
+	default:
+		oid, err := queryOid(ctx, t, NewDOid(v))
+		if err != nil {
+			oid = NewDOid(v)
+			oid.semanticType = t
+		}
+		return oid, nil
+	}
+}
diff --git a/pkg/sql/sem/tree/datum.go b/pkg/sql/sem/tree/datum.go
index c15ffe4d24eb..9cd7394066f6 100644
--- a/pkg/sql/sem/tree/datum.go
+++ b/pkg/sql/sem/tree/datum.go
@@ -4272,7 +4272,16 @@ func ParseDOid(ctx *EvalContext, s string, t *types.T) (*DOid, error) {
 		if err != nil {
 			return nil, err
 		}
-		return queryOid(ctx, t, NewDString(funcDef.Name))
+		if len(funcDef.Definition) > 1 {
+			return nil, pgerror.Newf(pgcode.AmbiguousAlias,
+				"more than one function named '%s'", funcDef.Name)
+		}
+		def := funcDef.Definition[0]
+		overload, ok := def.(*Overload)
+		if !ok {
+			return nil, errors.AssertionFailedf("invalid non-overload regproc %s", funcDef.Name)
+		}
+		return &DOid{semanticType: t, DInt: DInt(overload.Oid), name: funcDef.Name}, nil
 	case oid.T_regtype:
 		parsedTyp, err := ctx.Planner.GetTypeFromValidSQLSyntax(s)
 		if err == nil {
diff --git a/pkg/sql/sem/tree/function_definition.go b/pkg/sql/sem/tree/function_definition.go
index 0c8d2339e77d..3a0c76f6f699 100644
--- a/pkg/sql/sem/tree/function_definition.go
+++ b/pkg/sql/sem/tree/function_definition.go
@@ -10,7 +10,10 @@
 
 package tree
 
-import "github.com/cockroachdb/cockroach/pkg/sql/sqltelemetry"
+import (
+	"github.com/cockroachdb/cockroach/pkg/sql/sqltelemetry"
+	"github.com/lib/pq/oid"
+)
 
 // FunctionDefinition implements a reference to the (possibly several)
 // overloads for a built-in function.
@@ -159,6 +162,11 @@ func NewFunctionDefinition(
 // for every builtin function. Initialized by builtins.init().
 var FunDefs map[string]*FunctionDefinition
 
+// OidToBuiltinName contains a map from the hashed OID of all builtin functions
+// to their name. We populate this from the pg_catalog.go file in the sql
+// package because of dependency issues: we can't use oidHasher from this file.
+var OidToBuiltinName map[oid.Oid]string
+
 // Format implements the NodeFormatter interface.
 func (fd *FunctionDefinition) Format(ctx *FmtCtx) {
 	ctx.WriteString(fd.Name)
diff --git a/pkg/sql/sem/tree/overload.go b/pkg/sql/sem/tree/overload.go
index 87c3f5d3f51c..bcf0b2d0a23c 100644
--- a/pkg/sql/sem/tree/overload.go
+++ b/pkg/sql/sem/tree/overload.go
@@ -22,6 +22,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/errors"
+	"github.com/lib/pq/oid"
 )
 
 // SpecializedVectorizedBuiltin is used to map overloads
@@ -85,6 +86,10 @@ type Overload struct {
 	// volatility against Postgres's volatility at test time.
 	// This should be used with caution.
 	IgnoreVolatilityCheck bool
+
+	// Oid is the cached oidHasher.BuiltinOid result for this Overload. It's
+	// populated at init-time.
+	Oid oid.Oid
 }
 
 // params implements the overloadImpl interface.