Fix memory leak with group id

This commit fixes a memory leak that was being caused by hooks
hanging on to the geofence group ids past the life of the object.

internal/server/crud.go

@@ -308,6 +308,7 @@ func (server *Server) cmdDel(msg *Message) (res resp.Value, d commandDetails, er
 			found = true
 		}
 	}
+	server.groupDisconnectObject(d.key, d.id)
 	d.command = "del"
 	d.updated = found
 	d.timestamp = time.Now()
@@ -372,6 +373,7 @@ func (server *Server) cmdPdel(msg *Message) (res resp.Value, d commandDetails, e
 			} else {
 				d.children[i] = dc
 			}
+			server.groupDisconnectObject(dc.key, dc.id)
 		}
 		if atLeastOneNotDeleted {
 			var nchildren []*commandDetails
@@ -423,6 +425,7 @@ func (server *Server) cmdDrop(msg *Message) (res resp.Value, d commandDetails, e
 		d.key = "" // ignore the details
 		d.updated = false
 	}
+	server.groupDisconnectCollection(d.key)
 	d.command = "drop"
 	d.timestamp = time.Now()
 	switch msg.OutputType {
@@ -503,10 +506,12 @@ func (server *Server) cmdFlushDB(msg *Message) (res resp.Value, d commandDetails
 		return
 	}
 	server.cols = btree.NewNonConcurrent(byCollectionKey)
+	server.groupHooks = btree.NewNonConcurrent(byGroupHook)
+	server.groupObjects = btree.NewNonConcurrent(byGroupObject)
 	server.hooks = make(map[string]*Hook)
 	server.hooksOut = make(map[string]*Hook)
-	server.hookTree = rtree.RTree{}
+	server.hookTree = &rtree.RTree{}
-	server.hookCross = rtree.RTree{}
+	server.hookCross = &rtree.RTree{}
 	d.command = "flushdb"
 	d.updated = true
 	d.timestamp = time.Now()

internal/server/fence.go

@@ -195,23 +195,16 @@ func fenceMatch(
 	}
 	sw.mu.Unlock()
 
-	if fence.groups == nil {
-		fence.groups = make(map[string]string)
-	}
-	groupkey := details.key + ":" + details.id
 	var group string
-	var ok bool
 	if detect == "enter" {
-		group = bsonID()
+		group = sw.s.groupConnect(hookName, details.key, details.id)
-		fence.groups[groupkey] = group
 	} else if detect == "cross" {
-		group = bsonID()
+		sw.s.groupDisconnect(hookName, details.key, details.id)
-		delete(fence.groups, groupkey)
+		group = sw.s.groupConnect(hookName, details.key, details.id)
 	} else {
-		group, ok = fence.groups[groupkey]
+		group = sw.s.groupGet(hookName, details.key, details.id)
-		if !ok {
+		if group == "" {
-			group = bsonID()
+			group = sw.s.groupConnect(hookName, details.key, details.id)
-			fence.groups[groupkey] = group
 		}
 	}
 	var msgs []string

internal/server/group.go

@@ -0,0 +1,150 @@
+package server
+
+import (
+	"github.com/tidwall/btree"
+)
+
+func byGroupHook(va, vb interface{}) bool {
+	a, b := va.(*groupItem), vb.(*groupItem)
+	if a.hookName < b.hookName {
+		return true
+	}
+	if a.hookName > b.hookName {
+		return false
+	}
+	if a.colKey < b.colKey {
+		return true
+	}
+	if a.colKey > b.colKey {
+		return false
+	}
+	return a.objID < b.objID
+}
+
+func byGroupObject(va, vb interface{}) bool {
+	a, b := va.(*groupItem), vb.(*groupItem)
+	if a.colKey < b.colKey {
+		return true
+	}
+	if a.colKey > b.colKey {
+		return false
+	}
+	if a.objID < b.objID {
+		return true
+	}
+	if a.objID > b.objID {
+		return false
+	}
+	return a.hookName < b.hookName
+}
+
+type groupItem struct {
+	hookName string
+	colKey   string
+	objID    string
+	groupID  string
+}
+
+func newGroupItem(hookName, colKey, objID string) *groupItem {
+	groupID := bsonID()
+	g := &groupItem{}
+	// create a single string allocation
+	ustr := hookName + colKey + objID + groupID
+	var pos int
+	g.hookName = ustr[pos : pos+len(hookName)]
+	pos += len(hookName)
+	g.colKey = ustr[pos : pos+len(colKey)]
+	pos += len(colKey)
+	g.objID = ustr[pos : pos+len(objID)]
+	pos += len(objID)
+	g.groupID = ustr[pos : pos+len(groupID)]
+	pos += len(groupID)
+	return g
+}
+
+func (s *Server) groupConnect(hookName, colKey, objID string) (groupID string) {
+	g := newGroupItem(hookName, colKey, objID)
+	s.groupHooks.Set(g)
+	s.groupObjects.Set(g)
+	return g.groupID
+}
+
+func (s *Server) groupDisconnect(hookName, colKey, objID string) {
+	g := &groupItem{
+		hookName: hookName,
+		colKey:   colKey,
+		objID:    objID,
+	}
+	s.groupHooks.Delete(g)
+	s.groupObjects.Delete(g)
+}
+
+func (s *Server) groupGet(hookName, colKey, objID string) (groupID string) {
+	v := s.groupHooks.Get(&groupItem{
+		hookName: hookName,
+		colKey:   colKey,
+		objID:    objID,
+	})
+	if v != nil {
+		return v.(*groupItem).groupID
+	}
+	return ""
+}
+
+func deleteGroups(s *Server, groups []*groupItem) {
+	var hhint btree.PathHint
+	var ohint btree.PathHint
+	for _, g := range groups {
+		s.groupHooks.DeleteHint(g, &hhint)
+		s.groupObjects.DeleteHint(g, &ohint)
+	}
+}
+
+// groupDisconnectObject disconnects all hooks from provide object
+func (s *Server) groupDisconnectObject(colKey, objID string) {
+	var groups []*groupItem
+	s.groupObjects.Ascend(&groupItem{colKey: colKey, objID: objID},
+		func(v interface{}) bool {
+			g := v.(*groupItem)
+			if g.colKey != colKey || g.objID != objID {
+				return false
+			}
+			groups = append(groups, g)
+			return true
+		},
+	)
+	deleteGroups(s, groups)
+}
+
+// groupDisconnectCollection disconnects all hooks from objects in provided
+// collection.
+func (s *Server) groupDisconnectCollection(colKey string) {
+	var groups []*groupItem
+	s.groupObjects.Ascend(&groupItem{colKey: colKey},
+		func(v interface{}) bool {
+			g := v.(*groupItem)
+			if g.colKey != colKey {
+				return false
+			}
+			groups = append(groups, g)
+			return true
+		},
+	)
+	deleteGroups(s, groups)
+}
+
+// groupDisconnectHook disconnects all objects from provided hook.
+func (s *Server) groupDisconnectHook(hookName string) {
+	var groups []*groupItem
+	s.groupHooks.Ascend(&groupItem{hookName: hookName},
+		func(v interface{}) bool {
+			g := v.(*groupItem)
+			if g.hookName != hookName {
+				return false
+			}
+			groups = append(groups, g)
+			return true
+		},
+	)
+	deleteGroups(s, groups)
+}

internal/server/hooks.go

@@ -182,6 +182,7 @@ func (s *Server) cmdSetHook(msg *Message, chanCmd bool) (
 		prevHook.Close()
 		delete(s.hooks, name)
 		delete(s.hooksOut, name)
+		s.groupDisconnectHook(name)
 	}
 
 	d.updated = true
@@ -253,6 +254,8 @@ func (s *Server) cmdDelHook(msg *Message, chanCmd bool) (
 		// remove hook from maps
 		delete(s.hooks, hook.Name)
 		delete(s.hooksOut, hook.Name)
+		// remove any hook / object connections
+		s.groupDisconnectHook(hook.Name)
 		// remove hook from spatial index
 		if hook.Fence != nil && hook.Fence.obj != nil {
 			rect := hook.Fence.obj.Rect()
@@ -311,6 +314,8 @@ func (s *Server) cmdPDelHook(msg *Message, channel bool) (
 		// remove hook from maps
 		delete(s.hooks, hook.Name)
 		delete(s.hooksOut, hook.Name)
+		// remove any hook / object connections
+		s.groupDisconnectHook(hook.Name)
 		// remove hook from spatial index
 		if hook.Fence != nil && hook.Fence.obj != nil {
 			rect := hook.Fence.obj.Rect()

internal/server/search.go

@@ -23,7 +23,6 @@ type liveFenceSwitches struct {
 	obj  geojson.Object
 	cmd  string
 	roam roamSwitches
-	groups map[string]string
 }
 
 type roamSwitches struct {

internal/server/server.go

@@ -23,6 +23,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/tidwall/btree"
 	"github.com/tidwall/buntdb"
 	"github.com/tidwall/geojson"
@@ -37,8 +38,6 @@ import (
 	"github.com/tidwall/tile38/internal/endpoint"
 	"github.com/tidwall/tile38/internal/expire"
 	"github.com/tidwall/tile38/internal/log"
-
-	"github.com/prometheus/client_golang/prometheus"
 )
 
 var errOOM = errors.New("OOM command not allowed when used memory > 'maxmemory'")
@@ -118,9 +117,12 @@ type Server struct {
 	shrinking    bool             // aof shrinking flag
 	shrinklog    [][]string       // aof shrinking log
 	hooks        map[string]*Hook // hook name
-	hookCross  rtree.RTree      // hook spatial tree for "cross" geofences
+	hookCross    *rtree.RTree     // hook spatial tree for "cross" geofences
-	hookTree   rtree.RTree      // hook spatial tree for all
+	hookTree     *rtree.RTree     // hook spatial tree for all
 	hooksOut     map[string]*Hook // hooks with "outside" detection
+	groupHooks   *btree.BTree     // hooks that are connected to objects
+	groupObjects *btree.BTree     // objects that are connected to hooks
+
 	aofconnM   map[net.Conn]io.Closer
 	luascripts *lScriptMap
 	luapool    *lStatePool
@@ -153,6 +155,8 @@ func Serve(host string, port int, dir string, useHTTP bool, metricsAddr string)
 		lcond:     sync.NewCond(&sync.Mutex{}),
 		hooks:     make(map[string]*Hook),
 		hooksOut:  make(map[string]*Hook),
+		hookCross: &rtree.RTree{},
+		hookTree:  &rtree.RTree{},
 		aofconnM:  make(map[net.Conn]io.Closer),
 		started:   time.Now(),
 		conns:     make(map[int]*Client),
@@ -160,6 +164,9 @@ func Serve(host string, port int, dir string, useHTTP bool, metricsAddr string)
 		pubsub:    newPubsub(),
 		monconns:  make(map[net.Conn]bool),
 		cols:      btree.NewNonConcurrent(byCollectionKey),
+
+		groupHooks:   btree.NewNonConcurrent(byGroupHook),
+		groupObjects: btree.NewNonConcurrent(byGroupObject),
 	}
 
 	server.hookex.Expired = func(item expire.Item) {

internal/server/stats.go

@@ -338,6 +338,10 @@ func (s *Server) extStats(m map[string]interface{}) {
 	m["tile38_num_collections"] = s.cols.Len()
 	// Number of hooks in the database
 	m["tile38_num_hooks"] = len(s.hooks)
+	// Number of hook groups in the database
+	m["tile38_num_hook_groups"] = s.groupHooks.Len()
+	// Number of object groups in the database
+	m["tile38_num_object_groups"] = s.groupObjects.Len()
 
 	avgsz := 0
 	if points != 0 {