From 9b03178dfd45a8b84970d1f51ef747d6c78d5c99 Mon Sep 17 00:00:00 2001
From: Tobie Morgan Hitchcock <tobie@abcum.com>
Date: Fri, 27 Apr 2018 00:04:36 +0100
Subject: [PATCH] Improve live query performance and simplicity

---
 db/live.go   |   2 +-
 db/lives.go  | 140 ++++++++++++++++++++++++++-------------------------
 db/socket.go |   4 +-
 3 files changed, 75 insertions(+), 71 deletions(-)

diff --git a/db/live.go b/db/live.go
index b71cb2d4..b41ebd20 100644
--- a/db/live.go
+++ b/db/live.go
@@ -28,7 +28,7 @@ var sockets sync.Map
 func register(fib *fibre.Context, id string) func() {
 	return func() {
 
-		sockets.LoadOrStore(id, &socket{
+		sockets.Store(id, &socket{
 			fibre: fib,
 			items: make(map[string][]interface{}),
 			lives: make(map[string]*sql.LiveStatement),
diff --git a/db/lives.go b/db/lives.go
index e9c0455a..57ba65c1 100644
--- a/db/lives.go
+++ b/db/lives.go
@@ -47,83 +47,87 @@ func (d *document) lives(ctx context.Context, when method) (err error) {
 		return err
 	}
 
-	if len(lvs) > 0 {
+	// Loop over the currently running
+	// live queries so that we can pass
+	// change notifications to the socket.
 
-		for _, lv := range lvs {
+	for _, lv := range lvs {
 
-			if sck, ok := sockets.Load(lv.FB); ok {
+		// Check whether the change was made by
+		// the same connection as the live query,
+		// and if it is then don't notify changes.
 
-				var out interface{}
+		if id == lv.FB {
+			continue
+		}
 
-				// Create a new context for this socket
-				// which has the correct connection
-				// variables, and auth levels.
+		// Load the socket which owns the live
+		// query so that we can check the socket
+		// permissions, and send the notifications.
 
-				ctx = sck.(*socket).ctx(d.ns, d.db)
+		if sck, ok := sockets.Load(lv.FB); ok {
 
-				// Check whether the change was made by
-				// the same connection as the live query,
-				// and if it is then don't notify changes.
+			var out interface{}
 
-				if id == lv.FB {
-					continue
+			// Create a new context for this socket
+			// which has the correct connection
+			// variables, and auth levels.
+
+			ctx = sck.(*socket).ctx(d.ns, d.db)
+
+			// Check whether this live query has the
+			// necessary permissions to view this
+			// document, or continue to the next query.
+
+			ok, err = d.grant(ctx, when)
+			if err != nil {
+				continue
+			} else if !ok {
+				continue
+			}
+
+			// Check whether this document matches the
+			// filter conditions for the live query and
+			// if not, then continue to the next query.
+
+			ok, err = d.check(ctx, lv.Cond)
+			if err != nil {
+				continue
+			} else if !ok {
+				continue
+			}
+
+			switch lv.Diff {
+
+			// If the live query has specified to only
+			// receive diff changes, then there will be
+			// no projected fields for this query.
+
+			case true:
+
+				out, _ = d.yield(ctx, lv, sql.DIFF)
+
+			// If the query has projected fields which it
+			// wants to receive, then let's fetch these
+			// fields, and return them to the socket.
+
+			case false:
+
+				out, _ = d.yield(ctx, lv, sql.ILLEGAL)
+
+			}
+
+			switch when {
+			case _DELETE:
+				sck.(*socket).queue(id, lv.ID, "DELETE", d.id)
+			case _CREATE:
+				if out != nil {
+					sck.(*socket).queue(id, lv.ID, "CREATE", out)
 				}
-
-				// Check whether this live query has the
-				// necessary permissions to view this
-				// document, or continue to the next query.
-
-				ok, err = d.grant(ctx, when)
-				if err != nil {
-					continue
-				} else if !ok {
-					continue
+			case _UPDATE:
+				if out != nil {
+					sck.(*socket).queue(id, lv.ID, "UPDATE", out)
 				}
-
-				// Check whether this document matches the
-				// filter conditions for the live query and
-				// if not, then continue to the next query.
-
-				ok, err = d.check(ctx, lv.Cond)
-				if err != nil {
-					continue
-				} else if !ok {
-					continue
-				}
-
-				switch lv.Diff {
-
-				// If the live query has specified to only
-				// receive diff changes, then there will be
-				// no projected fields for this query.
-
-				case true:
-
-					out, _ = d.yield(ctx, lv, sql.DIFF)
-
-				// If the query has projected fields which it
-				// wants to receive, then let's fetch these
-				// fields, and return them to the socket.
-
-				case false:
-
-					out, _ = d.yield(ctx, lv, sql.ILLEGAL)
-
-				}
-
-				switch when {
-				case _DELETE:
-					sck.(*socket).queue(id, lv.ID, "DELETE", d.id)
-				case _CREATE:
-					if out != nil {
-						sck.(*socket).queue(id, lv.ID, "CREATE", out)
-					}
-				case _UPDATE:
-					if out != nil {
-						sck.(*socket).queue(id, lv.ID, "UPDATE", out)
-					}
-				}
-
 			}
 
 		}
diff --git a/db/socket.go b/db/socket.go
index eed5b8c6..8f9a9a7e 100644
--- a/db/socket.go
+++ b/db/socket.go
@@ -97,7 +97,7 @@ func (s *socket) clear(id string) (err error) {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
 
-	s.items[id] = nil
+	delete(s.items, id)
 
 	return
 
@@ -135,7 +135,7 @@ func (s *socket) flush(id string) (err error) {
 	// pending message notifications
 	// for this socket when done.
 
-	s.items[id] = nil
+	delete(s.items, id)
 
 	return