migrations: add additional symbol_history indexes

Indexes are added to these columns, since they are used in WHERE clauses
in various queries:

- sort_version
- goos
- goarch

For golang/go#37102

Change-Id: I5e4351cbfb06bac76bd8b5ed5e83421b8f615524
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/317309
Trust: Julie Qiu <[email protected]>
Run-TryBot: Julie Qiu <[email protected]>
TryBot-Result: kokoro <[email protected]>
Reviewed-by: Jonathan Amsterdam <[email protected]>

Author: julieqiu

migrations/000096_add_symbol_history_goos_goarch_idx.down.sql

@@ -0,0 +1,11 @@
+-- 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.
+
+BEGIN;
+
+DROP INDEX idx_symbol_history_module_sort_version;
+DROP INDEX idx_symbol_history_goos;
+DROP INDEX idx_symbol_history_goarch;
+
+END;

migrations/000096_add_symbol_history_goos_goarch_idx.up.sql

@@ -0,0 +1,11 @@
+-- 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.
+
+BEGIN;
+
+CREATE INDEX idx_symbol_history_sort_version ON symbol_history(sort_version);
+CREATE INDEX idx_symbol_history_goos ON symbol_history(goos);
+CREATE INDEX idx_symbol_history_goarch ON symbol_history(goarch);
+
+END;