[performance] Update indexes that were causing slow db queries (#855)

* add status.url index, use id desc in some indexes

* test account last posted

internal/db/bundb/account_test.go

@@ -139,6 +139,12 @@ func (suite *AccountTestSuite) TestUpdateAccount() {
 	suite.WithinDuration(time.Now(), noCache.UpdatedAt, 5*time.Second)
 }
 
+func (suite *AccountTestSuite) TestGetAccountLastPosted() {
+	lastPosted, err := suite.db.GetAccountLastPosted(context.Background(), suite.testAccounts["local_account_1"].ID)
+	suite.NoError(err)
+	suite.EqualValues(1653046675, lastPosted.Unix())
+}
+
 func (suite *AccountTestSuite) TestInsertAccountWithDefaults() {
 	key, err := rsa.GenerateKey(rand.Reader, 2048)
 	suite.NoError(err)

internal/db/bundb/migrations/20220926115233_indexes.go

@@ -0,0 +1,88 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors [email protected]
+
+   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 {
+			// index statuses on url to make searching them faster
+			if _, err := tx.
+				NewCreateIndex().
+				Model(&gtsmodel.Status{}).
+				Index("statuses_url_idx").
+				Column("url").
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// recreate account status index to allow id desc
+			if _, err := tx.
+				NewDropIndex().
+				Index("statuses_account_id_id_idx").
+				Exec(ctx); err != nil {
+				return err
+			}
+			if _, err := tx.
+				NewCreateIndex().
+				Model(&gtsmodel.Status{}).
+				Index("statuses_account_id_id_idx").
+				Column("account_id").
+				ColumnExpr("id DESC").
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// recreate statuses public timeline index to allow id desc
+			if _, err := tx.
+				NewDropIndex().
+				Index("statuses_public_timeline_idx").
+				Exec(ctx); err != nil {
+				return err
+			}
+			if _, err := tx.
+				NewCreateIndex().
+				Model(&gtsmodel.Status{}).
+				Index("statuses_public_timeline_idx").
+				Column("visibility").
+				ColumnExpr("id DESC").
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			return nil
+		})
+	}
+
+	down := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			return nil
+		})
+	}
+
+	if err := Migrations.Register(up, down); err != nil {
+		panic(err)
+	}
+}