From 5333fab870aac54e547801ac6ad080bc2d522b80 Mon Sep 17 00:00:00 2001
From: tidwall <joshbaker77@gmail.com>
Date: Sun, 10 Mar 2019 10:48:14 -0700
Subject: [PATCH] Recycle aof buffer

---
 internal/server/aof.go       |  7 ++++++-
 internal/server/aofshrink.go |  2 +-
 internal/server/follow.go    |  4 ++--
 internal/server/server.go    | 26 +++++++++++++++++++++++---
 4 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/internal/server/aof.go b/internal/server/aof.go
index c190d128..42a42946 100644
--- a/internal/server/aof.go
+++ b/internal/server/aof.go
@@ -115,12 +115,17 @@ func commandErrIsFatal(err error) bool {
 	return true
 }
 
-func (server *Server) flushAOF() {
+func (server *Server) flushAOF(sync bool) {
 	if len(server.aofbuf) > 0 {
 		_, err := server.aof.Write(server.aofbuf)
 		if err != nil {
 			panic(err)
 		}
+		if sync {
+			if err := server.aof.Sync(); err != nil {
+				panic(err)
+			}
+		}
 		server.aofbuf = server.aofbuf[:0]
 	}
 }
diff --git a/internal/server/aofshrink.go b/internal/server/aofshrink.go
index efc1c1c1..095cad79 100644
--- a/internal/server/aofshrink.go
+++ b/internal/server/aofshrink.go
@@ -236,7 +236,7 @@ func (server *Server) aofshrink() {
 			defer server.mu.Unlock()
 
 			// flush the aof buffer
-			server.flushAOF()
+			server.flushAOF(false)
 
 			aofbuf = aofbuf[:0]
 			for _, values := range server.shrinklog {
diff --git a/internal/server/follow.go b/internal/server/follow.go
index 42d27dc5..6d12dd26 100644
--- a/internal/server/follow.go
+++ b/internal/server/follow.go
@@ -165,7 +165,7 @@ func (c *Server) followHandleCommand(args []string, followc int, w io.Writer) (i
 		return c.aofsz, err
 	}
 	if len(c.aofbuf) > 10240 {
-		c.flushAOF()
+		c.flushAOF(false)
 	}
 	return c.aofsz, nil
 }
@@ -291,7 +291,7 @@ func (c *Server) followStep(host string, port int, followc int) error {
 			if aofsz >= int(aofSize) {
 				caughtUp = true
 				c.mu.Lock()
-				c.flushAOF()
+				c.flushAOF(false)
 				c.fcup = true
 				c.fcuponce = true
 				c.mu.Unlock()
diff --git a/internal/server/server.go b/internal/server/server.go
index 94f38922..59f80c4f 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -250,7 +250,7 @@ func Serve(host string, port int, dir string, http bool) error {
 			return err
 		}
 		defer func() {
-			server.flushAOF()
+			server.flushAOF(false)
 			server.aof.Sync()
 		}()
 	}
@@ -266,6 +266,7 @@ func Serve(host string, port int, dir string, http bool) error {
 	go server.watchLuaStatePool()
 	go server.watchAutoGC()
 	go server.backgroundExpiring()
+	go server.backgroundSyncAOF()
 	defer func() {
 		// Stop background routines
 		server.followc.add(1) // this will force any follow communication to die
@@ -487,7 +488,7 @@ func (server *Server) evioServe() error {
 		if atomic.LoadInt32(&server.aofdirty) != 0 {
 			server.mu.Lock()
 			defer server.mu.Unlock()
-			server.flushAOF()
+			server.flushAOF(false)
 			atomic.StoreInt32(&server.aofdirty, 1)
 		}
 	}
@@ -665,7 +666,7 @@ func (server *Server) netServe() error {
 							// prewrite
 							server.mu.Lock()
 							defer server.mu.Unlock()
-							server.flushAOF()
+							server.flushAOF(false)
 						}()
 						atomic.StoreInt32(&server.aofdirty, 0)
 					}
@@ -783,6 +784,25 @@ func (server *Server) watchLuaStatePool() {
 	}
 }
 
+// backgroundSyncAOF ensures that the aof buffer is does not grow too big.
+func (server *Server) backgroundSyncAOF() {
+	t := time.NewTicker(time.Second)
+	defer t.Stop()
+	for range t.C {
+		if server.stopServer.on() {
+			return
+		}
+		func() {
+			server.mu.Lock()
+			defer server.mu.Unlock()
+			if len(server.aofbuf) > 0 {
+				server.flushAOF(true)
+			}
+			server.aofbuf = nil
+		}()
+	}
+}
+
 func (server *Server) setCol(key string, col *collection.Collection) {
 	server.cols.Set(key, col)
 }