From c3e14cb9ae2ac98e307f17d60b1a248aebb7e513 Mon Sep 17 00:00:00 2001
From: Matthew Jaffee <jaffee@pilosa.com>
Date: Wed, 27 Oct 2021 15:08:58 -0500
Subject: [PATCH] don't fsync on RBF Open if WAL is empty

This is targeted at reducing startup times, especially on OSX where
the fsync calls seem to be taking an egregiously long time. I got one
index to go from ~1min to open to ~1sec. This looks safe to me, but
will get opinions from RBF experts.
---
 rbf/db.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/rbf/db.go b/rbf/db.go
index 4f88de259..68a41ac08 100644
--- a/rbf/db.go
+++ b/rbf/db.go
@@ -206,6 +206,13 @@ func (db *DB) checkpoint() error {
 		return nil // skip if transactions open
 	}
 
+	// Check if there are any WAL pages, if not do nothing as
+	// checkpointing and calling fsync can be very expensive even if
+	// there are no writes.
+	if db.walPageN == 0 {
+		return nil
+	}
+
 	for i := 0; i < db.walPageN; i++ {
 		page, err := db.readWALPageAt(i)
 		if err != nil {
@@ -245,7 +252,7 @@ func (db *DB) checkpoint() error {
 	db.walPageN = 0
 	db.pageMap = NewPageMap()
 
-	// Notify halted tranactions that the WAL has been checkpointed.
+	// Notify halted transactions that the WAL has been checkpointed.
 	db.haltCond.Broadcast()
 
 	return nil