sql/inspect: support AS OF SYSTEM TIME for historical descriptor access

Prior to this change, INSPECT could fail late during execution when
running AS OF SYSTEM TIME queries that referenced objects which did not
exist at the specified timestamp. For example, querying a database that
had not yet been created would trigger an internal error instead of a
clear user facing message.

This change updates INSPECT’s planning logic to detect such cases
earlier and return a more informative error (e.g. “database movr does
not exist”). It does this by using a fixed timestamp and avoiding leased
descriptors for ASOF queries.

Informs: #155483
Epic: CRDB-55075
Release note: none

Author: spilchen

pkg/sql/exec_util.go

@@ -2525,6 +2525,11 @@ func (p *planner) isAsOf(ctx context.Context, stmt tree.Statement) (*eval.AsOfSy
 		}
 		asOf = s.AsOf
 		forBackfill = true
+	case *tree.Inspect:
+		if s.AsOf.Expr == nil {
+			return nil, nil
+		}
+		asOf = s.AsOf
 	default:
 		return nil, nil
 	}

pkg/sql/inspect/inspect_plan.go

@@ -60,6 +60,20 @@ func newInspectRun(
 ) (inspectRun, error) {
 	var run inspectRun
 
+	avoidLeased := false
+	if aost := p.ExtendedEvalContext().AsOfSystemTime; aost != nil {
+		avoidLeased = true
+	}
+
+	if stmt.AsOf.Expr != nil {
+		asOf, err := p.EvalAsOfTimestamp(ctx, stmt.AsOf)
+		if err != nil {
+			return inspectRun{}, err
+		}
+		run.asOfTimestamp = asOf.Timestamp
+		avoidLeased = true
+	}
+
 	switch stmt.Typ {
 	case tree.InspectTable:
 		if table, err := p.ResolveExistingObjectEx(ctx, stmt.Table, true /* required */, tree.ResolveRequireTableDesc); err != nil {
@@ -68,13 +82,21 @@ func newInspectRun(
 			run.table = table
 		}
 
-		if db, err := p.Descriptors().ByIDWithLeased(p.Txn()).Get().Database(ctx, run.table.GetParentID()); err != nil {
+		dbGetter := p.Descriptors().ByIDWithLeased(p.Txn())
+		if avoidLeased {
+			dbGetter = p.Descriptors().ByIDWithoutLeased(p.Txn())
+		}
+		if db, err := dbGetter.Get().Database(ctx, run.table.GetParentID()); err != nil {
 			return inspectRun{}, err
 		} else {
 			run.db = db
 		}
 	case tree.InspectDatabase:
-		if db, err := p.Descriptors().ByNameWithLeased(p.Txn()).Get().Database(ctx, stmt.Database.ToUnresolvedName().String()); err != nil {
+		dbGetter := p.Descriptors().ByNameWithLeased(p.Txn())
+		if avoidLeased {
+			dbGetter = p.Descriptors().ByName(p.Txn())
+		}
+		if db, err := dbGetter.Get().Database(ctx, stmt.Database.ToUnresolvedName().String()); err != nil {
 			return inspectRun{}, err
 		} else {
 			run.db = db
@@ -105,7 +127,11 @@ func newInspectRun(
 		// Named indexes specified.
 		switch stmt.Typ {
 		case tree.InspectTable:
-			schema, err := p.Descriptors().ByIDWithLeased(p.Txn()).Get().Schema(ctx, run.table.GetParentSchemaID())
+			schemaGetter := p.Descriptors().ByIDWithLeased(p.Txn())
+			if avoidLeased {
+				schemaGetter = p.Descriptors().ByIDWithoutLeased(p.Txn())
+			}
+			schema, err := schemaGetter.Get().Schema(ctx, run.table.GetParentSchemaID())
 			if err != nil {
 				return inspectRun{}, err
 			}
@@ -133,14 +159,6 @@ func newInspectRun(
 		}
 	}
 
-	if stmt.AsOf.Expr != nil {
-		asOf, err := p.EvalAsOfTimestamp(ctx, stmt.AsOf)
-		if err != nil {
-			return inspectRun{}, err
-		}
-		run.asOfTimestamp = asOf.Timestamp
-	}
-
 	return run, nil
 }
 

pkg/sql/inspect_job.go

@@ -104,7 +104,15 @@ func TriggerInspectJob(
 func InspectChecksForDatabase(
 	ctx context.Context, p PlanHookState, db catalog.DatabaseDescriptor,
 ) ([]*jobspb.InspectDetails_Check, error) {
-	tables, err := p.Descriptors().ByNameWithLeased(p.Txn()).Get().GetAllTablesInDatabase(ctx, p.Txn(), db)
+	avoidLeased := false
+	if aost := p.ExtendedEvalContext().AsOfSystemTime; aost != nil {
+		avoidLeased = true
+	}
+	byNameGetter := p.Descriptors().ByNameWithLeased(p.Txn())
+	if avoidLeased {
+		byNameGetter = p.Descriptors().ByName(p.Txn())
+	}
+	tables, err := byNameGetter.Get().GetAllTablesInDatabase(ctx, p.Txn(), db)
 	if err != nil {
 		return nil, err
 	}

pkg/sql/logictest/testdata/logic_test/inspect

@@ -5,14 +5,18 @@
 # LogicTest: !fakedist !fakedist-vec-off !fakedist-disk !local-mixed-25.2 !local-mixed-25.3
 
 
+# Helper view to show the most recent INSPECT job.
+# We order by job ID (not creation time) because jobs run with AS OF SYSTEM
+# TIME use the AOST value as their creation timestamp rather than the current
+# time.
 statement ok
 CREATE VIEW last_inspect_job AS
 SELECT status, jsonb_array_length(
     crdb_internal.pb_to_json('cockroach.sql.jobs.jobspb.Payload', payload)->'inspectDetails'->'checks'
   ) AS num_checks
 FROM crdb_internal.system_jobs
 WHERE job_type = 'INSPECT'
-ORDER BY created DESC
+ORDER BY id DESC
 LIMIT 1
 
 # Make job adoption faster. This is needed to speed up DETACHED jobs.
@@ -22,6 +26,9 @@ SET CLUSTER SETTING jobs.registry.interval.adopt = '500ms';
 statement ok
 CREATE TABLE foo (c1 INT, c2 INT, INDEX idx_c1 (c1), INDEX idx_c2 (c2));
 
+let $foo_created_ts
+SELECT now()
+
 statement error pq: INSPECT is an experimental feature and is disabled by default
 INSPECT TABLE foo;
 
@@ -138,9 +145,8 @@ SELECT * FROM last_inspect_job;
 ----
 succeeded  1
 
-# TODO(155483): use a really old timestamp from before 'foo' was created.
 statement ok
-INSPECT TABLE foo AS OF SYSTEM TIME '-50ms' WITH OPTIONS INDEX (idx_c1,idx_c2);
+INSPECT TABLE foo AS OF SYSTEM TIME '$foo_created_ts' WITH OPTIONS INDEX (idx_c1,idx_c2);
 
 query TI
 SELECT * FROM last_inspect_job;
@@ -533,3 +539,28 @@ statement ok
 DROP TABLE refcursor_tbl;
 
 subtest end
+
+subtest inspect_old_aost
+
+let $inspect_old_ts
+SELECT now()
+
+statement ok
+CREATE TABLE t_aost (c1 INT, INDEX idx_c1 (c1));
+
+statement ok
+INSERT INTO t_aost VALUES (1), (2), (3);
+
+# Test INSPECT with an AOST that predates the table.
+# This should fail because the table descriptor doesn't exist at that timestamp.
+statement error pq: relation "t_aost" does not exist
+INSPECT TABLE t_aost AS OF SYSTEM TIME '$inspect_old_ts' WITH OPTIONS INDEX (idx_c1);
+
+# Test INSPECT with an AOST that predates the database.
+statement error pq: database "test" does not exist
+INSPECT TABLE t_aost AS OF SYSTEM TIME '1' WITH OPTIONS INDEX (idx_c1);
+
+statement ok
+DROP TABLE t_aost;
+
+subtest end