Address review feedback

cmd/soroban-rpc/internal/ledgerentry_storage/db.go

@@ -40,17 +40,28 @@ type LedgerEntryUpdaterTx interface {
 }
 
 type sqlDB struct {
-	db *sqlx.DB
+	db                  *sqlx.DB
+	postWriteCommitHook func() error
 }
 
 func OpenSQLiteDB(dbFilePath string) (DB, error) {
-	db, err := sqlx.Open("sqlite3", fmt.Sprintf("file:%s?_journal_mode=WAL", dbFilePath))
+	// 1. Use Write-Ahead Logging (WAL).
+	// 2. Disable WAL auto-checkpointing (we will do the checkpointing ourselves with wal_checkpoint pragmas
+	//    after every write transaction).
+	// 3. Use synchronous=NORMAL, which is faster and still safe in WAL mode.
+	db, err := sqlx.Open("sqlite3", fmt.Sprintf("file:%s?_journal_mode=WAL&_wal_autocheckpoint=0&_synchronous=NORMAL", dbFilePath))
 	if err != nil {
 		return nil, errors.Wrap(err, "open failed")
 	}
 
+	postWriteCommitHook := func() error {
+		_, err := db.Exec("PRAGMA wal_checkpoint(TRUNCATE)")
+		return err
+	}
+
 	ret := &sqlDB{
-		db: db,
+		db:                  db,
+		postWriteCommitHook: postWriteCommitHook,
 	}
 
 	if err = runMigrations(ret.db.DB, "sqlite3"); err != nil {
@@ -180,8 +191,9 @@ func (s *sqlDB) Close() error {
 }
 
 type ledgerUpdaterTx struct {
-	tx        *sqlx.Tx
-	stmtCache *sq.StmtCache
+	tx                  *sqlx.Tx
+	stmtCache           *sq.StmtCache
+	postWriteCommitHook func() error
 	// Value to set "latestSequence" to once we are done
 	forLedgerSequence uint32
 	maxBatchSize      int
@@ -196,11 +208,12 @@ func (s *sqlDB) NewLedgerEntryUpdaterTx(forLedgerSequence uint32, maxBatchSize i
 		return nil, err
 	}
 	ret := &ledgerUpdaterTx{
-		maxBatchSize:      maxBatchSize,
-		tx:                tx,
-		forLedgerSequence: forLedgerSequence,
-		buffer:            xdr.NewEncodingBuffer(),
-		keyToEntryBatch:   make(map[string]*string, maxBatchSize),
+		tx:                  tx,
+		postWriteCommitHook: s.postWriteCommitHook,
+		forLedgerSequence:   forLedgerSequence,
+		maxBatchSize:        maxBatchSize,
+		buffer:              xdr.NewEncodingBuffer(),
+		keyToEntryBatch:     make(map[string]*string, maxBatchSize),
 	}
 	ret.stmtCache = sq.NewStmtCache(tx)
 	return ret, nil
@@ -284,9 +297,18 @@ func (l *ledgerUpdaterTx) Done() error {
 		return err
 	}
 	if err := upsertLatestLedgerSequence(l.tx, l.forLedgerSequence); err != nil {
+		_ = l.tx.Rollback()
+		return err
+	}
+	if err := l.tx.Commit(); err != nil {
 		return err
 	}
-	return l.tx.Commit()
+	if l.postWriteCommitHook() != nil {
+		if err := l.postWriteCommitHook(); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func encodeLedgerKey(buffer *xdr.EncodingBuffer, key xdr.LedgerKey) (string, error) {