sql/schemachanger: set schema_locked automatically for declarative

Previously, the schema_locked setting had to be manually toggled by the
user before executing DDL on a table. This meant that setting /
unsetting schema_locked was a manual process for users. The declarative
schema changer makes it much easier to tie setting / unsetting the
locked setting within the schema change path. This patch adds a new
TRANSIENT_PUBLIC state that allows elements to be toggled. The builder
is modified to emit this schema_locked element in a TRANSIENT_PUBLIC
state.

Informs: #129694
Release note: None

Author: fqazi

pkg/ccl/schemachangerccl/backup_base_generated_test.go

@@ -45,7 +45,7 @@ func validateSchemaChangerState(d catalog.Descriptor, vea catalog.ValidationErro
 				i, got, d.GetID()))
 		}
 		switch t.TargetStatus {
-		case scpb.Status_PUBLIC, scpb.Status_ABSENT, scpb.Status_TRANSIENT_ABSENT:
+		case scpb.Status_PUBLIC, scpb.Status_ABSENT, scpb.Status_TRANSIENT_ABSENT, scpb.Status_TRANSIENT_PUBLIC:
 			// These are valid target status values.
 		default:
 			report(errors.Errorf("target %d is targeting an invalid status %s",

pkg/sql/catalog/internal/validate/schema_changer_state.go

@@ -83,34 +83,43 @@ CREATE TABLE t (i INT PRIMARY KEY, j INT, UNIQUE INDEX idx (j)) WITH (schema_loc
 statement ok
 INSERT INTO t SELECT i, i+1 FROM generate_series(1,10) AS tmp(i);
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER TABLE t ADD COLUMN k INT DEFAULT 30;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER TABLE t DROP COLUMN j;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER TABLE t RENAME TO t2;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER TABLE t RENAME COLUMN j TO j2;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER INDEX idx RENAME TO idx2;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER INDEX idx INVISIBLE;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 DROP INDEX idx;
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 CREATE INDEX idx2 ON t(j);
 
 statement ok
 CREATE TABLE ref (a INT PRIMARY KEY, b INT)
 
 # Locked tables cannot be referenced by foreign keys.
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "t" because it is locked
 ALTER TABLE ref ADD CONSTRAINT fk FOREIGN KEY (b) REFERENCES t(j);
 
@@ -125,18 +134,52 @@ statement ok
 COMMENT ON TABLE t IS 't is a table';
 COMMENT ON INDEX t@idx IS 'idx is an index';
 COMMENT ON COLUMN t.i IS 'i is a column';
+subtest end
+
+# Declarative schema change can automatically unset and set schema locked.
+subtest declarative_allows_schema_changes
 
+skipif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement ok
-ALTER TABLE t RESET (schema_locked)
+ALTER TABLE t ADD COLUMN k INT DEFAULT 30;
+
+skipif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
+statement ok
+CREATE INDEX idx2 ON t(j);
 
+skipif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
+statement ok
+DROP INDEX idx2;
+
+skipif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
+statement ok
+ALTER TABLE ref ADD CONSTRAINT fk FOREIGN KEY (b) REFERENCES t(j);
+
+skipif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
+statement ok
+ALTER TABLE t DROP COLUMN j CASCADE;
+
+# Confirm that the table definition still has schema_locked
+query I
+SELECT count(create_statement) FROM [SHOW CREATE TABLE t] WHERE create_statement LIKE '%schema_locked = true%'
+----
+1
+
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
+statement ok
+ALTER TABLE t SET (schema_locked = false);
+
+# Finally drop the table.
 statement ok
 DROP TABLE t;
+subtest end
 
 subtest zone_config
 
 statement ok
 ALTER TABLE ref SET (schema_locked = true);
 
+onlyif config local-mixed-24.3 local-mixed-25.1 local-legacy-schema-changer
 statement error pgcode 57000 schema changes are disallowed on table "ref" because it is locked
 ALTER TABLE ref CONFIGURE ZONE USING num_replicas = 11;
 

pkg/sql/logictest/testdata/logic_test/schema_locked

@@ -450,6 +450,10 @@ func (b buildCtx) AddTransient(element scpb.Element) {
 	b.Ensure(element, scpb.Transient, b.TargetMetadata())
 }
 
+func (b buildCtx) DropTransient(element scpb.Element) {
+	b.Ensure(element, scpb.TransientPublic, b.TargetMetadata())
+}
+
 // Drop implements the scbuildstmt.BuildCtx interface.
 func (b buildCtx) Drop(element scpb.Element) {
 	b.Ensure(element, scpb.ToAbsent, b.TargetMetadata())

pkg/sql/schemachanger/scbuild/build.go

@@ -62,7 +62,7 @@ func (b *builderState) QueryByID(id catid.DescID) scbuildstmt.ElementResultSet {
 func (b *builderState) Ensure(e scpb.Element, target scpb.TargetStatus, meta scpb.TargetMetadata) {
 	dst := b.getExistingElementState(e)
 	switch target {
-	case scpb.ToAbsent, scpb.ToPublic, scpb.Transient:
+	case scpb.ToAbsent, scpb.ToPublic, scpb.Transient, scpb.TransientPublic:
 		// Sanity check.
 	default:
 		panic(errors.AssertionFailedf("unsupported target %s", target.Status()))

pkg/sql/schemachanger/scbuild/builder_state.go

@@ -17,7 +17,7 @@ func AlterPolicy(b BuildCtx, n *tree.AlterPolicy) {
 	tableElems := b.ResolveTable(n.TableName, ResolveParams{
 		RequireOwnership: true,
 	})
-	panicIfSchemaChangeIsDisallowed(tableElems, n)
+	checkTableSchemaChangePrerequisites(b, tableElems, n)
 	tbl := tableElems.FilterTable().MustGetOneElement()
 
 	// Alter of a policy implies that it must exist.

pkg/sql/schemachanger/scbuild/internal/scbuildstmt/alter_policy.go

@@ -123,7 +123,7 @@ func AlterTable(b BuildCtx, n *tree.AlterTable) {
 		panic(pgerror.Newf(pgcode.ObjectNotInPrerequisiteState,
 			"table %q is being dropped, try again later", n.Table.Object()))
 	}
-	panicIfSchemaChangeIsDisallowed(elts, n)
+	checkTableSchemaChangePrerequisites(b, elts, n)
 	tn.ObjectNamePrefix = b.NamePrefix(tbl)
 	b.SetUnresolvedNameAnnotation(n.Table, &tn)
 	b.IncrementSchemaChangeAlterCounter("table")

pkg/sql/schemachanger/scbuild/internal/scbuildstmt/alter_table.go

@@ -281,7 +281,7 @@ func alterTableAddForeignKey(
 			"and is no longer supported."))
 	}
 	// Disallow schema change if the FK references a table whose schema is locked.
-	panicIfSchemaChangeIsDisallowed(b.QueryByID(referencedTableID), stmt)
+	checkTableSchemaChangePrerequisites(b, b.QueryByID(referencedTableID), stmt)
 
 	// 6. Check that temporary tables can only reference temporary tables, or,
 	// permanent tables can only reference permanent tables.

pkg/sql/schemachanger/scbuild/internal/scbuildstmt/alter_table_add_constraint.go

@@ -156,7 +156,7 @@ func astToZoneConfigObject(b BuildCtx, n *tree.SetZoneConfig) (zoneConfigObject,
 	}
 	tblName := zs.TableOrIndex.Table.ToUnresolvedObjectName()
 	elems := b.ResolvePhysicalTable(tblName, ResolveParams{})
-	panicIfSchemaChangeIsDisallowed(elems, n)
+	checkTableSchemaChangePrerequisites(b, elems, n)
 	var tableID catid.DescID
 	elems.ForEach(func(_ scpb.Status, _ scpb.TargetStatus, e scpb.Element) {
 		switch e := e.(type) {

pkg/sql/schemachanger/scbuild/internal/scbuildstmt/configure_zone.go

@@ -144,7 +144,7 @@ func CreateIndex(b BuildCtx, n *tree.CreateIndex) {
 			"cannot define PARTITION BY on an index if the table has a PARTITION ALL BY definition",
 		))
 	}
-	panicIfSchemaChangeIsDisallowed(relationElements, n)
+	checkTableSchemaChangePrerequisites(b, relationElements, n)
 
 	if !n.Type.SupportsSharding() && n.Sharded != nil {
 		panic(pgerror.Newf(pgcode.InvalidSQLStatementName,