migrations: validate constraints

Validate the constraints we established in the previous migration.

Change-Id: I3196bd9012ea20c32d2a0573c78c992d3ff212e8
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/321430
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>

migrations/000101_validate_constraints.down.sql

@@ -0,0 +1,5 @@
+-- Copyright 2021 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+-- Nothing to do.

migrations/000101_validate_constraints.up.sql

@@ -0,0 +1,13 @@
+-- Copyright 2021 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+-- These commands won't fail and should only set an internal bit in the DB marking the
+-- constraint as valid.
+-- They don't need to be run in a transaction.
+-- See https://www.postgresql.org/docs/12/sql-altertable.html, search for VALIDATE CONSTRAINT.
+
+ALTER TABLE symbol_history VALIDATE CONSTRAINT "symbol_history_module_path_id_fkey";
+ALTER TABLE symbol_history VALIDATE CONSTRAINT "symbol_history_package_path_id_fkey";
+ALTER TABLE symbol_search_documents VALIDATE CONSTRAINT "symbol_search_documents_package_path_id_fkey";
+ALTER TABLE latest_module_versions VALIDATE CONSTRAINT "latest_module_versions_module_path_id_fkey";