From 6bc04c8060d59099f5d4eadf7b1ad716f8799b33 Mon Sep 17 00:00:00 2001
From: Rod Vagg <rod@vagg.org>
Date: Thu, 2 May 2024 10:54:38 +1000
Subject: [PATCH] feat: cli,events: speed up backfill with temporary index

---
 chain/events/filter/index.go |  2 ++
 cmd/lotus-shed/indexes.go    | 57 +++++++++++++++++++++++++++++++++---
 2 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/chain/events/filter/index.go b/chain/events/filter/index.go
index 9bf7213c8..98cc54d20 100644
--- a/chain/events/filter/index.go
+++ b/chain/events/filter/index.go
@@ -32,6 +32,8 @@ var pragmas = []string{
 	"PRAGMA read_uncommitted = ON",
 }
 
+// Any changes to this schema should be matched for the `lotus-shed indexes backfill-events` command
+
 var ddls = []string{
 	`CREATE TABLE IF NOT EXISTS event (
 		id INTEGER PRIMARY KEY,
diff --git a/cmd/lotus-shed/indexes.go b/cmd/lotus-shed/indexes.go
index 12ebe0082..ed10ab215 100644
--- a/cmd/lotus-shed/indexes.go
+++ b/cmd/lotus-shed/indexes.go
@@ -7,6 +7,7 @@ import (
 	"path"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/mitchellh/go-homedir"
 	"github.com/urfave/cli/v2"
@@ -54,6 +55,16 @@ var backfillEventsCmd = &cli.Command{
 			Value: 2000,
 			Usage: "the number of epochs to backfill",
 		},
+		&cli.BoolFlag{
+			Name:  "temporary-index",
+			Value: false,
+			Usage: "use a temporary index to speed up the backfill process",
+		},
+		&cli.BoolFlag{
+			Name:  "vacuum",
+			Value: false,
+			Usage: "run VACUUM on the database after backfilling is complete; this will reclaim space from deleted rows, but may take a long time",
+		},
 	},
 	Action: func(cctx *cli.Context) error {
 		srv, err := lcli.GetFullNodeServices(cctx)
@@ -92,8 +103,12 @@ var backfillEventsCmd = &cli.Command{
 			return err
 		}
 
+		log.Infof(
+			"WARNING: If this command is run against a node that is currently collecting events with DisableHistoricFilterAPI=false, " +
+				"it may cause the node to fail to record recent events due to the need to obtain an exclusive lock on the database for writes.")
+
 		dbPath := path.Join(basePath, "sqlite", "events.db")
-		db, err := sql.Open("sqlite3", dbPath)
+		db, err := sql.Open("sqlite3", dbPath+"?_txlock=immediate")
 		if err != nil {
 			return err
 		}
@@ -105,6 +120,14 @@ var backfillEventsCmd = &cli.Command{
 			}
 		}()
 
+		if cctx.Bool("temporary-index") {
+			log.Info("creating temporary index (tmp_event_backfill_index) on event table to speed up backfill")
+			_, err := db.Exec("CREATE INDEX IF NOT EXISTS tmp_event_backfill_index ON event (height, tipset_key, tipset_key_cid, emitter_addr, event_index, message_cid, message_index, reverted);")
+			if err != nil {
+				return err
+			}
+		}
+
 		addressLookups := make(map[abi.ActorID]address.Address)
 
 		// TODO: We don't need this address resolution anymore once https://github.com/filecoin-project/lotus/issues/11594 lands
@@ -134,9 +157,19 @@ var backfillEventsCmd = &cli.Command{
 		var totalEntriesAffected int64
 
 		processHeight := func(ctx context.Context, cnt int, msgs []lapi.Message, receipts []*types.MessageReceipt) error {
-			tx, err := db.BeginTx(ctx, nil)
-			if err != nil {
-				return fmt.Errorf("failed to start transaction: %w", err)
+			var tx *sql.Tx
+			for {
+				var err error
+				tx, err = db.BeginTx(ctx, nil)
+				if err != nil {
+					if err.Error() == "database is locked" {
+						log.Warnf("database is locked, retrying in 200ms")
+						time.Sleep(200 * time.Millisecond)
+						continue
+					}
+					return err
+				}
+				break
 			}
 			defer tx.Rollback() //nolint:errcheck
 
@@ -312,6 +345,22 @@ var backfillEventsCmd = &cli.Command{
 
 		log.Infof("backfilling events complete, totalEventsAffected:%d, totalEntriesAffected:%d", totalEventsAffected, totalEntriesAffected)
 
+		if cctx.Bool("temporary-index") {
+			log.Info("dropping temporary index (tmp_event_backfill_index) on event table")
+			_, err := db.Exec("DROP INDEX IF EXISTS tmp_event_backfill_index;")
+			if err != nil {
+				fmt.Printf("ERROR: dropping index: %s", err)
+			}
+		}
+
+		if cctx.Bool("vacuum") {
+			log.Info("running VACUUM on the database")
+			_, err := db.Exec("VACUUM;")
+			if err != nil {
+				return fmt.Errorf("failed to run VACUUM on the database: %w", err)
+			}
+		}
+
 		return nil
 	},
 }