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pg_builtins.go
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pg_builtins.go
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// Copyright 2016 The Cockroach Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
package parser
import (
"errors"
"fmt"
"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgerror"
"github.com/lib/pq/oid"
)
// This file contains builtin functions that we implement primarily for
// compatibility with Postgres.
const notUsableInfo = "Not usable; exposed only for compatibility with PostgreSQL."
// typeBuiltinsHaveUnderscore is a map to keep track of which types have i/o
// builtins with underscores in between their type name and the i/o builtin
// name, like date_in vs int8int. There seems to be no other way to
// programmatically determine whether or not this underscore is present, hence
// the existence of this map.
var typeBuiltinsHaveUnderscore = map[oid.Oid]struct{}{
TypeAny.Oid(): {},
TypeDate.Oid(): {},
TypeDecimal.Oid(): {},
TypeInterval.Oid(): {},
TypeUUID.Oid(): {},
TypeTimestamp.Oid(): {},
TypeTimestampTZ.Oid(): {},
TypeTuple.Oid(): {},
}
// PGIOBuiltinPrefix returns the string prefix to a type's IO functions. This
// is either the type's postgres display name or the type's postgres display
// name plus an underscore, depending on the type.
func PGIOBuiltinPrefix(typ Type) string {
builtinPrefix := PGDisplayName(typ)
if _, ok := typeBuiltinsHaveUnderscore[typ.Oid()]; ok {
return builtinPrefix + "_"
}
return builtinPrefix
}
// initPGBuiltins adds all of the postgres builtins to the Builtins map.
func initPGBuiltins() {
for k, v := range pgBuiltins {
for i := range v {
v[i].category = categoryCompatibility
}
Builtins[k] = v
}
// Make non-array type i/o builtins.
for _, typ := range OidToType {
// Skip array types. We're doing them separately below.
if typ != TypeAny && typ != TypeIntVector && typ.Equivalent(TypeAnyArray) {
continue
}
builtinPrefix := PGIOBuiltinPrefix(typ)
for name, builtins := range makeTypeIOBuiltins(builtinPrefix, typ) {
Builtins[name] = builtins
}
}
// Make array type i/o builtins.
for name, builtins := range makeTypeIOBuiltins("array_", TypeAnyArray) {
Builtins[name] = builtins
}
}
func makeTypeIOBuiltin(argTypes typeList, returnType Type) []Builtin {
return []Builtin{
{
Types: argTypes,
ReturnType: fixedReturnType(returnType),
fn: func(_ *EvalContext, _ Datums) (Datum, error) { return nil, errors.New("unimplemented") },
Info: notUsableInfo,
},
}
}
// makeTypeIOBuiltins generates the 4 i/o builtins that Postgres implements for
// every type: typein, typeout, typerecv, and typsend. All 4 builtins are no-op,
// and only supported because ORMs sometimes use their names to form a map for
// client-side type encoding and decoding. See issue #12526 for more details.
func makeTypeIOBuiltins(builtinPrefix string, typ Type) map[string][]Builtin {
typname := typ.String()
return map[string][]Builtin{
builtinPrefix + "send": makeTypeIOBuiltin(ArgTypes{{typname, typ}}, TypeBytes),
// Note: PG takes type 2281 "internal" for these builtins, which we don't
// provide. We won't implement these functions anyway, so it shouldn't
// matter.
builtinPrefix + "recv": makeTypeIOBuiltin(ArgTypes{{"input", TypeAny}}, typ),
// Note: PG returns 'cstring' for these builtins, but we don't support that.
builtinPrefix + "out": makeTypeIOBuiltin(ArgTypes{{typname, typ}}, TypeBytes),
// Note: PG takes 'cstring' for these builtins, but we don't support that.
builtinPrefix + "in": makeTypeIOBuiltin(ArgTypes{{"input", TypeAny}}, typ),
}
}
var pgBuiltins = map[string][]Builtin{
// See https://www.postgresql.org/docs/9.6/static/functions-info.html.
"pg_backend_pid": {
Builtin{
Types: ArgTypes{},
ReturnType: fixedReturnType(TypeInt),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return NewDInt(-1), nil
},
Info: notUsableInfo,
},
},
// Postgres defines pg_get_expr as a function that "decompiles the internal form
// of an expression", which is provided in the pg_node_tree type. In Cockroach's
// pg_catalog implementation, we populate all pg_node_tree columns with the
// corresponding expression as a string, which means that this function can simply
// return the first argument directly. It also means we can ignore the second and
// optional third argument.
"pg_get_expr": {
Builtin{
Types: ArgTypes{
{"pg_node_tree", TypeString},
{"relation_oid", TypeOid},
},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, args Datums) (Datum, error) {
return args[0], nil
},
Info: notUsableInfo,
},
Builtin{
Types: ArgTypes{
{"pg_node_tree", TypeString},
{"relation_oid", TypeOid},
{"pretty_bool", TypeBool},
},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, args Datums) (Datum, error) {
return args[0], nil
},
Info: notUsableInfo,
},
},
// pg_get_indexdef functions like SHOW CREATE INDEX would if we supported that
// statement.
"pg_get_indexdef": {
Builtin{
Types: ArgTypes{
{"index_oid", TypeOid},
},
distsqlBlacklist: true,
ReturnType: fixedReturnType(TypeString),
fn: func(ctx *EvalContext, args Datums) (Datum, error) {
r, err := ctx.Planner.QueryRow(
ctx.Ctx(), "SELECT indexdef FROM pg_catalog.pg_indexes WHERE crdb_oid=$1", args[0])
if err != nil {
return nil, err
}
if len(r) == 0 {
return nil, pgerror.NewErrorf(pgerror.CodeInvalidParameterValueError, "unknown index (OID=%s)", args[0])
}
return r[0], nil
},
Info: notUsableInfo,
},
// The other overload for this function, pg_get_indexdef(index_oid,
// column_no, pretty_bool), is unimplemented, because it isn't used by
// supported ORMs.
},
"pg_typeof": {
// TODO(knz): This is a proof-of-concept until TypeAny works
// properly.
Builtin{
Types: ArgTypes{{"val", TypeAny}},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, args Datums) (Datum, error) {
return NewDString(args[0].ResolvedType().String()), nil
},
Info: notUsableInfo,
},
},
"pg_get_userbyid": {
Builtin{
Types: ArgTypes{
{"role_oid", TypeOid},
},
distsqlBlacklist: true,
ReturnType: fixedReturnType(TypeString),
fn: func(ctx *EvalContext, args Datums) (Datum, error) {
oid := args[0]
t, err := ctx.Planner.QueryRow(
ctx.Ctx(), "SELECT rolname FROM pg_catalog.pg_roles WHERE oid=$1", oid)
if err != nil {
return nil, err
}
if len(t) == 0 {
return NewDString(fmt.Sprintf("unknown (OID=%s)", args[0])), nil
}
return t[0], nil
},
Info: notUsableInfo,
},
},
"format_type": {
Builtin{
Types: ArgTypes{{"type_oid", TypeOid}, {"typemod", TypeInt}},
ReturnType: fixedReturnType(TypeString),
nullableArgs: true,
fn: func(ctx *EvalContext, args Datums) (Datum, error) {
oidArg := args[0]
if oidArg == DNull {
return DNull, nil
}
typ, ok := OidToType[oid.Oid(int(oidArg.(*DOid).DInt))]
if !ok {
return NewDString(fmt.Sprintf("unknown (OID=%s)", oidArg)), nil
}
return NewDString(typ.SQLName()), nil
},
Info: "Returns the SQL name of a data type that is " +
"identified by its type OID and possibly a type modifier. " +
"Currently, the type modifier is ignored.",
},
},
"col_description": {
Builtin{
Types: ArgTypes{{"table_oid", TypeOid}, {"column_number", TypeInt}},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return DNull, nil
},
Info: notUsableInfo,
},
},
"obj_description": {
Builtin{
Types: ArgTypes{{"object_oid", TypeOid}},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return DNull, nil
},
Info: notUsableInfo,
},
Builtin{
Types: ArgTypes{{"object_oid", TypeOid}, {"catalog_name", TypeString}},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return DNull, nil
},
Info: notUsableInfo,
},
},
"oid": {
Builtin{
Types: ArgTypes{{"int", TypeInt}},
ReturnType: fixedReturnType(TypeOid),
fn: func(_ *EvalContext, args Datums) (Datum, error) {
return NewDOid(*args[0].(*DInt)), nil
},
Info: "Converts an integer to an OID.",
},
},
"shobj_description": {
Builtin{
Types: ArgTypes{{"object_oid", TypeOid}, {"catalog_name", TypeString}},
ReturnType: fixedReturnType(TypeString),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return DNull, nil
},
Info: notUsableInfo,
},
},
"pg_try_advisory_lock": {
Builtin{
Types: ArgTypes{{"int", TypeInt}},
ReturnType: fixedReturnType(TypeBool),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return DBoolTrue, nil
},
Info: notUsableInfo,
},
},
"pg_advisory_unlock": {
Builtin{
Types: ArgTypes{{"int", TypeInt}},
ReturnType: fixedReturnType(TypeBool),
fn: func(_ *EvalContext, _ Datums) (Datum, error) {
return DBoolTrue, nil
},
Info: notUsableInfo,
},
},
// pg_table_is_visible returns true if the input oid corresponds to a table
// that is part of the databases on the search path.
// https://www.postgresql.org/docs/9.6/static/functions-info.html
"pg_table_is_visible": {
Builtin{
Types: ArgTypes{{"oid", TypeOid}},
ReturnType: fixedReturnType(TypeBool),
fn: func(ctx *EvalContext, args Datums) (Datum, error) {
oid := args[0]
t, err := ctx.Planner.QueryRow(ctx.Ctx(),
"SELECT nspname FROM pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n ON c.relnamespace=n.oid "+
"WHERE c.oid=$1 AND nspname=ANY(current_schemas(true));", oid)
if err != nil {
return nil, err
}
return MakeDBool(DBool(t != nil)), nil
},
Info: notUsableInfo,
},
},
}