hyperspace: event index v1=>v2 speed up migration.

chain/events/filter/index.go

@@ -417,24 +417,47 @@ func (ei *EventIndex) RunMigration(from, to int) error {
 		return nil
 	}
 
-	tx, err := ei.db.Begin()
-	if err != nil {
-		return err
+	if _, err := ei.db.Exec(`DROP TABLE IF EXISTS event_entry_v2`); err != nil {
+		return xerrors.Errorf("failed to drop old event_entry_v2 temporary table: %w", err)
 	}
-	defer tx.Rollback() //nolint
 
-	if _, err = tx.Exec(`ALTER TABLE event_entry ADD COLUMN codec INTEGER`); err != nil {
-		return xerrors.Errorf("failed to alter table event_entry to add codec column: %w", err)
+	// Create a temporary table that is a clone of the original table.
+	if _, err := ei.db.Exec(`CREATE TABLE IF NOT EXISTS event_entry_v2 (
+		event_id INTEGER,
+		indexed INTEGER NOT NULL,
+		flags BLOB NOT NULL,
+		key TEXT NOT NULL,
+		value BLOB NOT NULL
+	)`); err != nil {
+		return xerrors.Errorf("failed to create temporary table: %w", err)
+	}
+
+	if _, err := ei.db.Exec(`CREATE INDEX event_entry_value ON event_entry_v2(value)`); err != nil {
+		return xerrors.Errorf("failed to create index on event_entry: %w", err)
+	}
+
+	if _, err := ei.db.Exec(`CREATE INDEX event_entry_event_id ON event_entry_v2(event_id)`); err != nil {
+		return xerrors.Errorf("failed to create index on event_entry: %w", err)
+	}
+
+	if _, err := ei.db.Exec(`INSERT INTO event_entry_v2(event_id, indexed, flags, key, value) SELECT * FROM event_entry`); err != nil {
+		return xerrors.Errorf("failed to copy all rows to temporary table: %w", err)
+	}
+
+	// Operate on the temporary table.
+
+	if _, err := ei.db.Exec(`ALTER TABLE event_entry_v2 ADD COLUMN codec INTEGER`); err != nil {
+		return xerrors.Errorf("failed to alter table event_entry_v2 to add codec column: %w", err)
 	}
 
-	log.Warnw("[migration v1=>v2] event_entry table schema updated")
+	log.Warnw("[migration v1=>v2] event_entry_v2 table schema updated")
 
-	res, err := tx.Exec(`UPDATE event_entry SET codec = ? WHERE codec IS NULL`, 0x55)
+	res, err := ei.db.Exec(`UPDATE event_entry_v2 SET codec = ? WHERE codec IS NULL`, 0x55)
 	if err != nil {
-		return xerrors.Errorf("failed to update table event_entry to set codec 0x55: %w", err)
+		return xerrors.Errorf("failed to update table event_entry_v2 to set codec 0x55: %w", err)
 	}
 	n, _ := res.RowsAffected()
-	log.Warnw("[migration v1=>v2] updated %d event entries with codec=0x55", "affected", n)
+	log.Warnw("[migration v1=>v2] updated event entries with codec=0x55", "affected", n)
 
 	var keyRewrites = [][]string{
 		{"topic1", "t1"},
@@ -446,15 +469,15 @@ func (ei *EventIndex) RunMigration(from, to int) error {
 
 	for _, r := range keyRewrites {
 		from, to := r[0], r[1]
-		res, err := tx.Exec(`UPDATE event_entry SET key = ? WHERE key = ?`, to, from)
+		res, err := ei.db.Exec(`UPDATE event_entry_v2 SET key = ? WHERE key = ?`, to, from)
 		if err != nil {
 			return xerrors.Errorf("failed to update entries from key %s to key %s: %w", from, to, err)
 		}
 		n, _ := res.RowsAffected()
 		log.Warnw("[migration v1=>v2] rewrote entry keys", "from", from, "to", to, "affected", n)
 	}
 
-	update, err := tx.Prepare(`UPDATE event_entry SET value = ? WHERE value = ?`)
+	update, err := ei.db.Prepare(`UPDATE event_entry_v2 SET value = ? WHERE event_id = ? and value = ?`)
 	if err != nil {
 		return xerrors.Errorf("failed to prepare update statement: %w", err)
 	}
@@ -468,21 +491,20 @@ func (ei *EventIndex) RunMigration(from, to int) error {
 		"t4": {},
 	}
 
-	if _, err = tx.Exec(`CREATE TABLE tmp AS SELECT key, value FROM event_entry`); err != nil {
-		return xerrors.Errorf("failed to create temporary table: %w", err)
-	}
-
-	// Pull the values out and process them in Go land before updating.
-	rows, err := tx.Query(`SELECT key, value FROM tmp`)
+	// Pull the values out out of the original table, process them in Go land before updating, and the update the v2 table.
+	rows, err := ei.db.Query(`SELECT event_id, key, value FROM event_entry`)
 	if err != nil {
+		_ = rows.Close()
 		return xerrors.Errorf("failed to select values: %w", err)
 	}
 
 	var i int
 	for rows.Next() {
+		var eventId int
 		var key string
 		var before []byte
-		if err := rows.Scan(&key, &before); err != nil {
+		if err := rows.Scan(&eventId, &key, &before); err != nil {
+			_ = rows.Close()
 			return xerrors.Errorf("failed to scan from query: %w", err)
 		}
 		reader := bytes.NewReader(before)
@@ -499,22 +521,45 @@ func (ei *EventIndex) RunMigration(from, to int) error {
 			copy(pvalue[32-len(after):], after)
 			after = pvalue
 		}
-		if _, err := update.Exec(after, before); err != nil {
-			return xerrors.Errorf("failed to scan from query: %w", err)
+		if _, err := update.Exec(after, eventId, before); err != nil {
+			log.Warnw("failed to update entry", "value_before", before, "value_after", after)
 		}
 
 		if i++; i%500 == 0 {
 			log.Warnw("[migration v1=>v2] processed values", "count", i)
 		}
 	}
+	_ = rows.Close()
 
 	log.Warnw("[migration v1=>v2] processed all values", "count", i)
 
-	if _, err = tx.Exec(`DROP TABLE tmp`); err != nil {
-		return xerrors.Errorf("failed to drop temporary table: %w", err)
+	if _, err := ei.db.Exec(`DROP INDEX event_entry_event_id`); err != nil {
+		log.Warnw("[migration v1=>v2] failed to drop index event_entry_event_id; ignoring")
+	}
+
+	if _, err := ei.db.Exec(`DROP INDEX event_entry_value`); err != nil {
+		log.Warnw("[migration v1=>v2] failed to drop index event_entry_value; ignoring")
+	}
+
+	// Critical section.
+
+	log.Warnw("[migration v1=>v2] beginning transaction")
+
+	tx, err := ei.db.Begin()
+	if err != nil {
+		return xerrors.Errorf("failed to begin transaction: %w", err)
+	}
+	defer tx.Rollback() //nolint
+
+	if _, err = tx.Exec(`DROP TABLE event_entry`); err != nil {
+		return xerrors.Errorf("failed to drop original table: %w", err)
+	}
+
+	if _, err = tx.Exec(`ALTER TABLE event_entry_v2 RENAME TO event_entry`); err != nil {
+		return xerrors.Errorf("failed to rename table: %w", err)
 	}
 
-	log.Warnw("[migration v1=>v2] dropped temporary table")
+	log.Warnw("[migration v1=>v2] replaced original table")
 
 	if _, err = tx.Exec(`INSERT INTO _meta (version) VALUES (2)`); err != nil {
 		return xerrors.Errorf("failed to update schema version: %w", err)

chain/events/filter/index_migration_test.go

@@ -0,0 +1,13 @@
+package filter
+
+import (
+	"fmt"
+	"testing"
+
+	logging "github.com/ipfs/go-log/v2"
+)
+
+func TestMigration(t *testing.T) {
+	_ = logging.SetLogLevel("event_index", "INFO")
+	fmt.Println(NewEventIndex("/Users/raul/hyperspace-test/sqlite/events.db"))
+}