.

wcfs/wcfs.go

@@ -541,35 +541,33 @@ type blkLoadState struct {
 // See "3) for */head/data the following invariant is maintained..."
 type zodbCacheControl struct {}
 
-func (cc *zodbCacheControl) WantEvict(obj zodb.IPersistent) bool {
+func (_ *zodbCacheControl) PCacheClassify(obj zodb.IPersistent) zodb.PCachePolicy {
 	switch obj.(type) {
-	default:
-		return true
-
-	// XXX ZBlk should be in ghost state - else we keep ZBlk data in cache
+	// ZBlk* should be in cache but without data
 	case *ZBlk0:
+		return zodb.PCachePinObject | zodb.PCacheNonTemporal
 	case *ZBlk1:
+		return zodb.PCachePinObject | zodb.PCacheNonTemporal
+
+	// ZBigFile btree index should be in cache with data
 	case *btree.LOBTree:
+		return zodb.PCachePinObject | zodb.PCacheKeepState
 	case *btree.LOBucket:
+		return zodb.PCachePinObject | zodb.PCacheKeepState
+
+	// don't let ZData to pollute the cache
+	case *ZData:
+		return zodb.PCacheNonTemporal
 
 	// for performance reason we also keep ZBigFile in cache.
 	//
 	// ZBigFile is top-level object that is used on every block load, and
 	// it would be a waste to evict ZBigFile state from cache.
 	case *ZBigFile:
-
-	// FIXME we need to keep ZBigFile in cache: even if we keep a pointer
-	// to ZBigFile, but it is allowed to drop its state, it will release
-	// pointer to LOBTree object and, consequently, that LOBTree object,
-	// even if it was marked not to be released from cache will be GC'ed by
-	// go runtime, and the cache will loose its weak reference to it.
-	// XXX however we cannot protect ZBigFile from releasing state - as
-	// any object can be explicitly invalidated.
-	//
-	// FIXME -> teach zodb.LiveCache to keep object by itself
+		return zodb.PCachePinObject | zodb.PCacheKeepState
 	}
 
-	return false
+	return 0
 }
 
 func traceWatch(format string, argv ...interface{}) {
@@ -1521,7 +1519,7 @@ func main() {
 
 	// open zodb storage/db/connection
 	ctx := context.Background()	// XXX + timeout?
-	zstor, err := zodb.OpenStorage(ctx, zurl, &zodb.OpenOptions{
+	zstor, err := zodb.Open(ctx, zurl, &zodb.OpenOptions{
 		ReadOnly: true,
 	})
 	if err != nil {