[performance] Optimize local timeline + local status count queries (#3892)

* [performance] Optimize local timeline + local status count queries

* remove if not exists from create view

1 files changed, 87 insertions, 0 deletions

diff --git a/internal/db/bundb/migrations/20250310094108_statuses_count_query_optimize.go b/internal/db/bundb/migrations/20250310094108_statuses_count_query_optimize.go
new file mode 100644
index 000000000..b20340f32
--- /dev/null
+++ b/internal/db/bundb/migrations/20250310094108_statuses_count_query_optimize.go
@@ -0,0 +1,87 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package migrations
+
+import (
+	"context"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/uptrace/bun"
+)
+
+func init() {
+	up := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+
+			// Add new local statuses count view.
+			in := []int16{
+				int16(gtsmodel.VisibilityPublic),
+				int16(gtsmodel.VisibilityUnlocked),
+				int16(gtsmodel.VisibilityFollowersOnly),
+				int16(gtsmodel.VisibilityMutualsOnly),
+			}
+			if _, err := tx.
+				NewRaw(
+					"CREATE VIEW ? AS "+
+						"SELECT COUNT(*) FROM ? "+
+						"WHERE (? = ?) AND (? IN (?)) AND (? = ?)",
+					bun.Ident("statuses_local_count_view"),
+					bun.Ident("statuses"),
+					bun.Ident("local"), true,
+					bun.Ident("visibility"), bun.In(in),
+					bun.Ident("pending_approval"), false,
+				).
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// Drop existing local index.
+			if _, err := tx.
+				NewDropIndex().
+				Index("statuses_local_idx").
+				IfExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// Add new multicolumn local statuses
+			// index that works for the local count
+			// view and the local timeline query.
+			if _, err := tx.
+				NewCreateIndex().
+				Table("statuses").
+				Index("statuses_local_idx").
+				Column("local", "visibility", "pending_approval").
+				ColumnExpr("? DESC", bun.Ident("id")).
+				IfNotExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			return nil
+		})
+	}
+
+	down := func(ctx context.Context, db *bun.DB) error {
+		return nil
+	}
+
+	if err := Migrations.Register(up, down); err != nil {
+		panic(err)
+	}
+}