X LRU reorder works ok

go/neo/client/cache.go

@@ -126,7 +126,6 @@ func (c *Cache) Load(xid zodb.Xid) (data []byte, serial zodb.Tid, err error) {
 
 	// rce is already in cache - use it
 	if !rceNew {
-		//panic(0)
 		<-rce.ready
 		c.gcMu.Lock()
 		rce.inLRU.MoveBefore(&c.lru)
@@ -161,7 +160,8 @@ func (c *Cache) Load(xid zodb.Xid) (data []byte, serial zodb.Tid, err error) {
 func (c *Cache) Prefetch(xid zodb.Xid) {
 	rce, rceNew := c.lookupRCE(xid)
 
-	// XXX!rceNew -> adjust LRU?
+	// !rceNew -> no need to adjust LRU - it will be adjusted by further actual data Load
+	// XXX or it is better to adjust LRU here too?
 
 	// spawn loading in the background if rce was not yet loaded
 	if rceNew {

go/neo/client/cache_test.go

@@ -221,6 +221,7 @@ func TestCache(t *testing.T) {
 	ok1(len(oce1.rcev) == 1)
 	ok1(oce1.rcev[0] == rce1_b4)
 	checkRCE(rce1_b4, 4, 0, nil, &zodb.ErrXidMissing{xidlt(1,4)})
+	checkMRU(rce1_b4)
 
 	// load <6 -> new rce entry with data
 	checkLoad(xidlt(1,6), hello, 4, nil)
@@ -228,10 +229,12 @@ func TestCache(t *testing.T) {
 	rce1_b6 := oce1.rcev[1]
 	checkRCE(rce1_b6, 6, 4, hello, nil)
 	checkOCE(1, rce1_b4, rce1_b6)
+	checkMRU(rce1_b6, rce1_b4)
 
 	// load <5 -> <5 merged with <6
 	checkLoad(xidlt(1,5), hello, 4, nil)
 	checkOCE(1, rce1_b4, rce1_b6)
+	checkMRU(rce1_b6, rce1_b4)
 
 	// load <7 -> <6 merged with <7
 	checkLoad(xidlt(1,7), hello, 4, nil)
@@ -240,6 +243,7 @@ func TestCache(t *testing.T) {
 	ok1(rce1_b7 != rce1_b6)
 	checkRCE(rce1_b7, 7, 4, hello, nil)
 	checkOCE(1, rce1_b4, rce1_b7)
+	checkMRU(rce1_b7, rce1_b4)
 
 	// load <8 -> ioerr + new rce
 	checkLoad(xidlt(1,8), nil, 0, ioerr)
@@ -247,6 +251,7 @@ func TestCache(t *testing.T) {
 	rce1_b8 := oce1.rcev[2]
 	checkRCE(rce1_b8, 8, 0, nil, ioerr)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8)
+	checkMRU(rce1_b8, rce1_b7, rce1_b4)
 
 	// load <10 -> ioerr + new rce (IO errors are not merged)
 	checkLoad(xidlt(1,10), nil, 0, ioerr)
@@ -254,6 +259,7 @@ func TestCache(t *testing.T) {
 	rce1_b10 := oce1.rcev[3]
 	checkRCE(rce1_b10, 10, 0, nil, ioerr)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10)
+	checkMRU(rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	// load <11 -> new data rce, not merged with ioerr @<10
 	checkLoad(xidlt(1,11), world, 10, nil)
@@ -261,6 +267,7 @@ func TestCache(t *testing.T) {
 	rce1_b11 := oce1.rcev[4]
 	checkRCE(rce1_b11, 11, 10, world, nil)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b11)
+	checkMRU(rce1_b11, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	// load <12 -> <11 merged with <12
 	checkLoad(xidlt(1,12), world, 10, nil)
@@ -269,6 +276,7 @@ func TestCache(t *testing.T) {
 	ok1(rce1_b12 != rce1_b11)
 	checkRCE(rce1_b12, 12, 10, world, nil)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b12)
+	checkMRU(rce1_b12, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	// simulate case where <14 and <16 were loaded in parallel, both are ready
 	// but <14 takes oce lock first before <16 and so <12 is not yet merged
@@ -281,17 +289,20 @@ func TestCache(t *testing.T) {
 	rce1_b16.data = world
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b12, rce1_b16)
 	ok1(!rce1_b16.loaded())
+	checkMRU(rce1_b12, rce1_b10, rce1_b8, rce1_b7, rce1_b4) // no <16 yet
 
 	// (lookup <14 while <16 is not yet loaded so <16 is not picked
 	//  automatically at lookup phase)
 	rce1_b14, new14 := c.lookupRCE(xidlt(1,14))
 	ok1(new14)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b12, rce1_b14, rce1_b16)
+	checkMRU(rce1_b12, rce1_b10, rce1_b8, rce1_b7, rce1_b4) // no <14 and <16 yet
 
 	// (now <16 becomes ready but not yet takes oce lock)
 	close(rce1_b16.ready)
 	ok1(rce1_b16.loaded())
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b12, rce1_b14, rce1_b16)
+	checkMRU(rce1_b12, rce1_b10, rce1_b8, rce1_b7, rce1_b4) // no <14 and <16 yet
 
 	// (<14 also becomes ready and takes oce lock first, merging <12 and <14 into <16)
 	c.loadRCE(rce1_b14, 1)
@@ -299,6 +310,7 @@ func TestCache(t *testing.T) {
 	checkRCE(rce1_b16, 16, 10, world, nil)
 	checkRCE(rce1_b12, 12, 10, world, nil)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b16)
+	checkMRU(rce1_b16, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	// load =17 -> <16 merged with <18
 	checkLoad(xideq(1,17), nil, 0, &zodb.ErrXidMissing{xideq(1,17)})
@@ -307,6 +319,7 @@ func TestCache(t *testing.T) {
 	ok1(rce1_b18 != rce1_b16)
 	checkRCE(rce1_b18, 18, 10, world, nil)
 	checkOCE(1,  rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b18)
+	checkMRU(rce1_b18, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	// load =18 -> new <19
 	checkLoad(xideq(1,18), www, 18, nil)
@@ -314,6 +327,7 @@ func TestCache(t *testing.T) {
 	rce1_b19 := oce1.rcev[5]
 	checkRCE(rce1_b19, 19, 18, www, nil)
 	checkOCE(1,  rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b18, rce1_b19)
+	checkMRU(rce1_b19, rce1_b18, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	// load =19 -> <19 merged with <20
 	checkLoad(xideq(1,19), nil, 0, &zodb.ErrXidMissing{xideq(1,19)})
@@ -322,7 +336,7 @@ func TestCache(t *testing.T) {
 	ok1(rce1_b20 != rce1_b19)
 	checkRCE(rce1_b20, 20, 18, www, nil)
 	checkOCE(1,  rce1_b4, rce1_b7, rce1_b8, rce1_b10, rce1_b18, rce1_b20)
-
+	checkMRU(rce1_b20, rce1_b18, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 
 	// ---- verify rce lookup for must be cached entries ----
@@ -368,6 +382,7 @@ func TestCache(t *testing.T) {
 	c.loadRCE(rce1_b9, 1)
 	checkRCE(rce1_b9, 9, 0, nil, ioerr)
 	checkOCE(1, rce1_b4, rce1_b7, rce1_b8, rce1_b9, rce1_b10, rce1_b18, rce1_b20)
+	checkMRU(rce1_b9, rce1_b20, rce1_b18, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
 
 	checkLookup(xideq(1,8), rce1_b9)
 	checkLookup(xidlt(1,8), rce1_b8)
@@ -390,6 +405,16 @@ func TestCache(t *testing.T) {
 	checkLookup(xideq(1,1), rce1_b4)
 	checkLookup(xidlt(1,1), rce1_b4)
 
+	// ---- verify how LRU changes for in-cache loads ----
+	checkMRU(rce1_b9, rce1_b20, rce1_b18, rce1_b10, rce1_b8, rce1_b7, rce1_b4)
+
+	checkLoad(xidlt(1,7), hello, 4, nil)
+	checkMRU(rce1_b7, rce1_b9, rce1_b20, rce1_b18, rce1_b10, rce1_b8, rce1_b4)
+
+	checkLoad(xidlt(1,18), world, 10, nil)
+	checkMRU(rce1_b18, rce1_b7, rce1_b9, rce1_b20, rce1_b10, rce1_b8, rce1_b4)
+
+
 	// XXX verify LRU eviction
 	// XXX verify db inconsistency checks
 	// XXX verify loading with before > cache.before