Merge cockroachdb#71440

71440: sql/catalog/resolver: return UndefinedDatabase in more cases r=ajwerner a=ajwerner

In 21.1 and prior, we returned UndefinedDatabase (3D000) in cases where a
table name was used to signify a virtual table and the database did not
exist. It turns out that this behavior was important. It existed for
arbitrary implementation reasons. When that code was refactored
earlier in the 21.2 release, the behavior was removed. Now we restore
that behavior and make the behavior more consistent. When we know that
we're trying to resolve a relation in the current database and we know
that the current database does not exist, we now return the
UndefinedDatabase error.

Fixes cockroachdb#71495

Release note (bug fix): In prior betas of 21.2, some error codes returned when
looking for a descriptor in a non-existent database were changed from
UndefinedDatabase (3D000) to UndefinedObject (42704). The behavior has been
reverted and more generally name resolution when the current database is
undefined will return UndefinedDatabase.

Co-authored-by: Andrew Werner <[email protected]>

pkg/ccl/logictestccl/testdata/logic_test/as_of

@@ -11,19 +11,19 @@ CREATE TABLE t (
 statement ok
 INSERT INTO t VALUES (2)
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 SELECT * FROM t AS OF SYSTEM TIME follower_read_timestamp()
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 SELECT * FROM t AS OF SYSTEM TIME experimental_follower_read_timestamp()
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN; SET TRANSACTION AS OF SYSTEM TIME follower_read_timestamp(); SELECT * FROM t
 
 statement ok
 ROLLBACK
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN AS OF SYSTEM TIME follower_read_timestamp(); SELECT * FROM t
 
 statement ok
@@ -32,13 +32,13 @@ ROLLBACK
 statement ok
 SET DEFAULT_TRANSACTION_USE_FOLLOWER_READS TO TRUE
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 SELECT * FROM t
 
 statement error pq: cannot execute CREATE DATABASE in a read-only transaction
 CREATE DATABASE IF NOT EXISTS d2
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN; SELECT * FROM t
 
 statement ok
@@ -74,13 +74,13 @@ BEGIN; CREATE DATABASE IF NOT EXISTS d2; COMMIT
 statement ok
 SET SESSION CHARACTERISTICS AS TRANSACTION AS OF SYSTEM TIME follower_read_timestamp()
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 SELECT * FROM t
 
 statement error pq: cannot execute CREATE DATABASE in a read-only transaction
 CREATE DATABASE IF NOT EXISTS d2
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN; SELECT * FROM t
 
 statement ok

pkg/sql/catalog/resolver/resolver.go

@@ -361,6 +361,11 @@ func GetForDatabase(
 // components because LookupObject retains those components. This is error
 // prone and exists only for backwards compatibility with certain error
 // reporting behaviors.
+//
+// Note also that if the implied current database does not exist and the name
+// is either unqualified or qualified by a virtual schema, an error will be
+// returned to indicate that the database does not exist. This error will be
+// returned regardless of the value set on the Required flag.
 func ResolveExisting(
 	ctx context.Context,
 	u *tree.UnresolvedObjectName,
@@ -387,11 +392,10 @@ func ResolveExisting(
 		// schema name is for a virtual schema.
 		_, isVirtualSchema := catconstants.VirtualSchemaNames[u.Schema()]
 		if isVirtualSchema || curDb != "" {
-			if found, prefix, result, err = r.LookupObject(ctx, lookupFlags, curDb, u.Schema(), u.Object()); found ||
-				err != nil || isVirtualSchema {
-				prefix.ExplicitDatabase = false
-				prefix.ExplicitSchema = true
-				if !found && err == nil && isVirtualSchema && prefix.Database == nil {
+			if found, prefix, result, err = r.LookupObject(
+				ctx, lookupFlags, curDb, u.Schema(), u.Object(),
+			); found || err != nil || isVirtualSchema {
+				if !found && err == nil && prefix.Database == nil { // && isVirtualSchema
 					// If the database was not found during the lookup for a virtual schema
 					// we should return a database not found error. We will use the prefix
 					// information to confirm this, since its possible that someone might
@@ -402,6 +406,10 @@ func ResolveExisting(
 					// or databases.
 					err = sqlerrors.NewUndefinedDatabaseError(curDb)
 				}
+				// Special case the qualification of virtual schema accesses for
+				// backwards compatibility.
+				prefix.ExplicitDatabase = false
+				prefix.ExplicitSchema = true
 				return found, prefix, result, err
 			}
 		}
@@ -417,11 +425,23 @@ func ResolveExisting(
 
 	// This is a naked object name. Use the search path.
 	iter := searchPath.Iter()
+	foundDatabase := false
 	for next, ok := iter.Next(); ok; next, ok = iter.Next() {
-		if found, prefix, result, err = r.LookupObject(ctx, lookupFlags, curDb, next,
-			u.Object()); found || err != nil {
+		if found, prefix, result, err = r.LookupObject(
+			ctx, lookupFlags, curDb, next, u.Object(),
+		); found || err != nil {
 			return found, prefix, result, err
 		}
+		foundDatabase = foundDatabase || prefix.Database != nil
+	}
+
+	// If we have a database, and we didn't find it, then we're never going to
+	// find it because it must not exist. This error return path is a bit of
+	// a rough edge, but it preserves backwards compatibility and makes sure
+	// we return a database does not exist error in cases where the current
+	// database definitely does not exist.
+	if curDb != "" && !foundDatabase {
+		return false, prefix, nil, sqlerrors.NewUndefinedDatabaseError(curDb)
 	}
 	return false, prefix, nil, nil
 }

pkg/sql/catalog/resolver/resolver_test.go

@@ -129,6 +129,8 @@ func (f *fakeMetadata) LookupObject(
 				if !hasDb {
 					return false, prefix, nil, nil
 				}
+				prefix.Database = dbdesc.NewBuilder(&descpb.DatabaseDescriptor{Name: dbName}).
+					BuildImmutableDatabase()
 			}
 			// Db valid, check the table name.
 			for tbIdx, tb := range v.tables {
@@ -148,6 +150,8 @@ func (f *fakeMetadata) LookupObject(
 	for i := range f.knownCatalogs {
 		c := &f.knownCatalogs[i]
 		if dbName == string(c.ctName) {
+			prefix.Database = dbdesc.NewBuilder(&descpb.DatabaseDescriptor{Name: dbName}).
+				BuildImmutableDatabase()
 			for j := range c.schemas {
 				s := &c.schemas[j]
 				if scName == string(s.scName) {

pkg/sql/logictest/testdata/logic_test/as_of

@@ -32,7 +32,7 @@ SELECT * FROM t AS OF SYSTEM TIME cluster_logical_timestamp()
 statement error pq: subqueries are not allowed in AS OF SYSTEM TIME
 SELECT * FROM t AS OF SYSTEM TIME (SELECT '-1h'::INTERVAL)
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 SELECT * FROM t AS OF SYSTEM TIME '-1h'
 
 query T noticetrace

pkg/sql/logictest/testdata/logic_test/distsql_stats

@@ -199,7 +199,7 @@ s1               {a}           256        4               0
 
 # Test AS OF SYSTEM TIME
 
-statement error pgcode 42P01 relation "data" does not exist
+statement error pgcode 3D000 database "test" does not exist
 CREATE STATISTICS s2 ON a FROM data AS OF SYSTEM TIME '2017'
 
 statement ok

pkg/sql/logictest/testdata/logic_test/prepare

@@ -1019,7 +1019,7 @@ ap35145
 statement ok
 DROP DATABASE d35145
 
-query error relation "pg_settings" does not exist
+query error pgcode 3D000 database "d35145" does not exist
 EXECUTE display_appname
 
 statement ok
@@ -1035,7 +1035,7 @@ ap35145
 statement ok
 CREATE DATABASE d35145_2; SET database = d35145_2; DROP DATABASE d35145_2
 
-query error relation "pg_settings" does not exist
+query error pgcode 3D000 database "d35145_2" does not exist
 EXECUTE display_appname
 
 # Check what happens when the stmt is executed over no db whatsoever.

pkg/sql/logictest/testdata/logic_test/rename_database

@@ -47,7 +47,7 @@ statement ok
 SET sql_safe_updates = FALSE;
  ALTER DATABASE test RENAME TO u
 
-statement error pgcode 42P01 relation "kv" does not exist
+statement error pgcode 3D000 database "test" does not exist
 SELECT * FROM kv
 
 statement error target database or schema does not exist

pkg/sql/logictest/testdata/logic_test/scrub

@@ -111,13 +111,13 @@ EXPERIMENTAL SCRUB TABLE test.fk_parent WITH OPTIONS CONSTRAINT (fkey)
 
 # Test AS OF SYSTEM TIME
 
-statement error pgcode 42P01 relation "xz" does not exist
+statement error pgcode 3D000 database "test" does not exist
 EXPERIMENTAL SCRUB TABLE xz AS OF SYSTEM TIME '2017' WITH OPTIONS PHYSICAL
 
-statement error pgcode 42P01 relation "xz" does not exist
+statement error pgcode 3D000 database "test" does not exist
 EXPERIMENTAL SCRUB TABLE xz AS OF SYSTEM TIME '2017' WITH OPTIONS INDEX ALL
 
-statement error pgcode 42P01 relation "xz" does not exist
+statement error pgcode 3D000 database "test" does not exist
 EXPERIMENTAL SCRUB TABLE xz AS OF SYSTEM TIME '2017' WITH OPTIONS CONSTRAINT ALL
 
 # Test scrubbing sequences.

pkg/sql/logictest/testdata/logic_test/txn_as_of

@@ -7,13 +7,13 @@ INSERT INTO t VALUES (2)
 # Verify that transacations can be used for historical reads using BEGIN
 # or SET TRANSACTION
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN AS OF SYSTEM TIME '-1h'; SELECT * FROM t
 
 statement ok
 COMMIT
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN; SET TRANSACTION AS OF SYSTEM TIME '-1h'; SELECT * FROM t
 
 statement ok
@@ -59,13 +59,13 @@ BEGIN AS OF SYSTEM TIME '-1h'; SELECT * FROM t AS OF SYSTEM TIME '-1h'
 statement ok
 COMMIT
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN AS OF SYSTEM TIME '2018-12-30'; SELECT * FROM t AS OF SYSTEM TIME '2018-12-30'
 
 statement ok
 COMMIT
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 BEGIN; SET TRANSACTION AS OF SYSTEM TIME '2018-12-30'; SELECT * FROM t AS OF SYSTEM TIME '2018-12-30'
 
 statement ok
@@ -111,7 +111,7 @@ COMMIT
 statement ok
 BEGIN AS OF SYSTEM TIME '-1h'; SET TRANSACTION PRIORITY HIGH;
 
-statement error pq: relation "t" does not exist
+statement error pgcode 3D000 pq: database "test" does not exist
 SELECT * FROM t
 
 statement ok