Merge branch 'keydbpro' into PRO_RELEASE_6

Former-commit-id: c03c45a1a1bf3c92a75804e123e34ea394adad07

monkey/monkey.py

@@ -0,0 +1,209 @@
+import keydb
+import random
+import sched, time
+import socket
+import asyncore
+import threading
+import sys
+from pprint import pprint
+
+# Parameters
+numclients = 50
+#numkeys = 1000000
+numkeys  = 100000
+
+# Globals
+ops=0
+s = sched.scheduler(time.time, time.sleep)
+g_exit = False
+
+def _buildResp(*args):
+    result = "*" + str(len(args)) + "\r\n"
+    for v in args:
+        result = result + "$" + str(len(v)) + "\r\n"
+        result = result + v + "\r\n"
+    return result.encode('utf-8')
+
+class Client(asyncore.dispatcher):
+    def __init__(self, host, port):
+        asyncore.dispatcher.__init__(self)
+        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.connect((host, port))
+        self.buf = b''
+        self.inbuf = b''
+        self.callbacks = list()
+
+    def handle_connect(self):
+        pass
+
+    def handle_read(self):
+        self.inbuf += self.recv(8192)
+        self.parse_response()
+
+    def handle_write(self):
+        sent = self.send(self.buf)
+        self.buf = self.buf[sent:]
+
+    def handle_close(self):
+        self.close()
+
+    def writable(self):
+        return len(self.buf) > 0
+
+    def parse_array(self, startpos):
+        assert(self.inbuf[startpos] == ord('*'))
+        endrange = self.inbuf[startpos+1:].find(ord('\r')) + 1 + startpos
+        assert(endrange > 0)
+        numargs = int(self.inbuf[startpos+1:endrange])
+        assert(numargs > 0)
+        args = list()
+        startpos = endrange + 2 # plus 1 gets us to the '\n' and the next gets us to the start char
+
+        while len(args) < numargs:
+            # We're parsing entries of the form "$N\r\nnnnnnn\r\n"
+            if startpos >= len(self.inbuf):
+                return # Not the full response
+            if self.inbuf[startpos] == ord('*'):
+                startpos, arr = self.parse_array(startpos)
+                args.append(arr)
+            else:
+                assert(self.inbuf[startpos] == ord('$'))
+                startpos = startpos + 1
+                endrange = self.inbuf[startpos:].find(b'\r')
+                if endrange < 0:
+                    return
+                endrange += startpos
+                assert(endrange <= len(self.inbuf))
+                length = int(self.inbuf[startpos:endrange])
+                if length < 0:
+                    return
+                startpos = endrange + 2
+                assert((startpos + length) <= len(self.inbuf))
+                assert(self.inbuf[startpos+length] == ord('\r'))
+                assert(self.inbuf[startpos+length+1] == ord('\n'))
+                args.append(self.inbuf[startpos:(startpos+length)])
+                startpos += length + 2
+        assert(len(args) == numargs)
+        return startpos, args
+
+    def parse_response(self):
+        if len(self.inbuf) == 0:
+            return
+        
+        while len(self.inbuf) > 0:
+            if self.inbuf[0] == ord('+') or self.inbuf[0] == ord('-') or self.inbuf[0] == ord(':'):
+                # This is a single line response
+                endpos = self.inbuf.find(b'\n')
+                if endpos < 0:
+                    return  # incomplete response
+                self.callbacks[0](self, self.inbuf[0:endpos-1])
+                self.callbacks.pop(0)
+                self.inbuf = self.inbuf[endpos+1:]
+
+            elif self.inbuf[0] == ord('*'):
+                #RESP response
+                try:
+                    startpos, args = self.parse_array(0)
+                except:
+                    return # Not all data here yet
+                self.callbacks[0](self, args)
+                self.callbacks.pop(0)
+                self.inbuf = self.inbuf[startpos:]
+            else:
+                print("ERROR: Unknown response:")
+                pprint(self.inbuf)
+                assert(False)
+
+
+    def default_result_handler(self, result):
+        pprint(result)
+
+    # Public Methods
+    def set(self, key, val, callback = default_result_handler):
+        self.buf += _buildResp("set", key, val)
+        self.callbacks.append(callback)
+
+    def lpush(self, key, val, callback = default_result_handler):
+        self.buf += _buildResp("lpush", key, val)
+        self.callbacks.append(callback)
+
+    def delete(self, key, callback = default_result_handler):
+        self.buf += _buildResp("del", key)
+        self.callbacks.append(callback)
+
+    def scan(self, iter, match=None, count=None, callback = default_result_handler):
+        args = ["scan", str(iter)]
+        if match != None:
+            args.append("MATCH")
+            args.append(match)
+        if count != None:
+            args.append("COUNT")
+            args.append(str(count))
+        self.buf += _buildResp(*args)
+        self.callbacks.append(callback)
+
+    def get(self, key, callback = None):
+       return 
+
+
+def getrandomkey():
+    return str(random.randrange(0, numkeys))
+
+def handle_lpush_response(c, resp):
+    global ops
+    if resp != None:
+        ops = ops + 1
+        assert(resp[0] == ord(':'))
+    c.lpush("list_" + getrandomkey(), 'bardsklfjkldsjfdlsjflksdfjklsdjflksd kldsjflksd jlkdsjf lksdjklds jrfklsdjfklsdjfkl', handle_lpush_response)
+
+def handle_set_response(c, resp):
+    global ops
+    if resp != None:
+        ops = ops + 1
+        assert(resp[0] == ord('+'))
+    c.set("str_" + getrandomkey(), 'bardsklfjkldsjfdlsjflksdfjklsdjflksd kldsjflksd jlkdsjf lksdjklds jrfklsdjfklsdjfkl', handle_set_response)
+
+def handle_del_response(c, resp):
+    global ops
+    if resp != None:
+        ops = ops + 1
+    c.delete("list_" + getrandomkey(), handle_del_response)
+
+def scan_callback(c, resp):
+    global ops
+    nextstart = int(resp[0])
+    c.scan(nextstart, count=500, callback=scan_callback)
+    ops = ops+1
+
+def stats_thread():
+    global ops
+    global g_exit
+    while not g_exit:
+        time.sleep(1)
+        print("Ops per second: " + str(ops))
+        ops = 0
+
+def main():
+    global g_exit
+    clients = []
+
+    for i in range(numclients):
+        clients.append(Client('127.0.0.1', 6379))
+        for i in range (10):
+            handle_lpush_response(clients[-1], None)
+        #handle_set_response(clients[-1], None)
+
+    scan_client = Client('127.0.0.1', 6379)
+    scan_client.scan(0, count=500, callback=scan_callback)
+
+    del_client = Client('127.0.0.1', 6379)
+    handle_del_response(del_client, None)
+
+    threading.Thread(target=stats_thread).start()
+    asyncore.loop()
+    g_exit = True
+    sys.exit(0)
+    print("DONE")
+
+if __name__ == "__main__":
+    main()

src/AsyncWorkQueue.cpp

@@ -49,6 +49,11 @@ void AsyncWorkQueue::WorkerThreadMain()
     }
 
     listRelease(vars.clients_pending_asyncwrite);
+
+    std::unique_lock<fastlock> lockf(serverTL->lockPendingWrite);
+    serverTL->vecclientsProcess.clear();
+    serverTL->clients_pending_write.clear();
+    std::atomic_thread_fence(std::memory_order_seq_cst);
 }
 
 bool AsyncWorkQueue::removeClientAsyncWrites(client *c)

src/Makefile

@@ -55,7 +55,9 @@ ifneq ($(strip $(SANITIZE)),)
 	USEASM=false
 endif
 
-
+ifeq ($(CHECKED),true)
+	CXXFLAGS+= -DCHECKED_BUILD
+endif
 
 # Do we use our assembly spinlock? X64 only
 ifeq ($(uname_S),Linux)

src/cron.cpp

@@ -31,7 +31,8 @@ void cronCommand(client *c)
     if (getLongLongFromObjectOrReply(c, c->argv[ARG_EXPIRE], &interval, "missing expire time") != C_OK)
         return;
 
-    long long base = g_pserver->mstime;
+    long long base;
+    __atomic_load(&g_pserver->mstime, &base, __ATOMIC_ACQUIRE);
     if (getLongLongFromObject(c->argv[ARG_EXPIRE+1], &base) == C_OK) {
         arg_offset++;
         std::swap(base, interval);
@@ -120,18 +121,20 @@ void executeCronJobExpireHook(const char *key, robj *o)
     else
     {
         job->startTime += job->interval;
-        if (job->startTime < (uint64_t)g_pserver->mstime)
+        mstime_t mstime;
+        __atomic_load(&g_pserver->mstime, &mstime, __ATOMIC_ACQUIRE);
+        if (job->startTime < (uint64_t)mstime)
         {
             // If we are more than one interval in the past then fast forward to
             //  the first interval still in the future.  If startTime wasn't zero align
             //  this to the original startTime, if it was zero align to now
             if (job->startTime == job->interval)
             {   // startTime was 0
-                job->startTime = g_pserver->mstime + job->interval;
+                job->startTime = mstime + job->interval;
             }
             else
             {
-                auto delta = g_pserver->mstime - job->startTime;
+                auto delta = mstime - job->startTime;
                 auto multiple = (delta / job->interval)+1;
                 job->startTime += job->interval * multiple;
             }

src/db.cpp

@@ -1713,7 +1713,8 @@ void setExpire(client *c, redisDb *db, robj *key, robj *subkey, long long when)
 
     /* Update TTL stats (exponential moving average) */
     /*  Note: We never have to update this on expiry since we reduce it by the current elapsed time here */
-    long long now = g_pserver->mstime;
+    mstime_t now;
+    __atomic_load(&g_pserver->mstime, &now, __ATOMIC_ACQUIRE);
     db->avg_ttl -= (now - db->last_expire_set); // reduce the TTL by the time that has elapsed
     if (db->expireSize() == 0)
         db->avg_ttl = 0;
@@ -1894,7 +1895,7 @@ int keyIsExpired(const redisDbPersistentDataSnapshot *db, robj *key) {
      * open object in a next call, if the next call will see the key expired,
      * while the first did not. */
     else if (serverTL->fixed_time_expire > 0) {
-        now = g_pserver->mstime;
+        __atomic_load(&g_pserver->mstime, &now, __ATOMIC_ACQUIRE);
     }
     /* For the other cases, we want to use the most fresh time we have. */
     else {
@@ -2588,6 +2589,7 @@ void redisDbPersistentData::ensure(const char *sdsKey, dictEntry **pde)
 {
     serverAssert(sdsKey != nullptr);
     serverAssert(FImplies(*pde != nullptr, dictGetVal(*pde) != nullptr));    // early versions set a NULL object, this is no longer valid
+    serverAssert(m_refCount == 0);
     std::unique_lock<fastlock> ul(g_expireLock);
 
     // First see if the key can be obtained from a snapshot
@@ -2781,7 +2783,7 @@ redisDbPersistentData::~redisDbPersistentData()
     if (m_spdbSnapshotHOLDER != nullptr)
         endSnapshot(m_spdbSnapshotHOLDER.get());
     
-    //serverAssert(m_pdbSnapshot == nullptr);
+    serverAssert(m_pdbSnapshot == nullptr);
     serverAssert(m_refCount == 0);
     //serverAssert(m_pdict->iterators == 0);
     serverAssert(m_pdictTombstone == nullptr || m_pdictTombstone->iterators == 0);
@@ -2853,16 +2855,16 @@ bool redisDbPersistentData::removeCachedValue(const char *key)
     return true;
 }
 
+redisDbPersistentData::redisDbPersistentData() {
+    m_dictChanged = dictCreate(&dictChangeDescType, nullptr);
+}
+
 void redisDbPersistentData::trackChanges(bool fBulk, size_t sizeHint)
 {
     m_fTrackingChanges.fetch_add(1, std::memory_order_relaxed);
     if (fBulk)
         m_fAllChanged.fetch_add(1, std::memory_order_acq_rel);
 
-    if (m_dictChanged == nullptr) {
-        m_dictChanged = dictCreate(&dictChangeDescType, nullptr);
-    }
-
     if (sizeHint > 0)
         dictExpand(m_dictChanged, sizeHint, false);
 }

src/dict.cpp

@@ -129,6 +129,7 @@ int _dictInit(dict *d, dictType *type,
     d->rehashidx = -1;
     d->iterators = 0;
     d->asyncdata = nullptr;
+    d->refcount = 1;
     return DICT_OK;
 }
 
@@ -195,7 +196,7 @@ int dictMerge(dict *dst, dict *src)
     }
 
     size_t expectedSize = dictSize(src) + dictSize(dst);
-    if (dictSize(src) > dictSize(dst))
+    if (dictSize(src) > dictSize(dst) && src->asyncdata == nullptr && dst->asyncdata == nullptr)
     {
         std::swap(*dst, *src);
         std::swap(dst->iterators, src->iterators);
@@ -369,8 +370,14 @@ int dictRehash(dict *d, int n) {
     return 1;
 }
 
+dictAsyncRehashCtl::dictAsyncRehashCtl(struct dict *d, dictAsyncRehashCtl *next) : dict(d), next(next) {
+    queue.reserve(c_targetQueueSize);
+    __atomic_fetch_add(&d->refcount, 1, __ATOMIC_RELEASE);
+}
+
 dictAsyncRehashCtl *dictRehashAsyncStart(dict *d, int buckets) {
-    if (!dictIsRehashing(d)) return 0;
+    assert(d->type->asyncfree != nullptr);
+    if (!dictIsRehashing(d) || d->iterators != 0) return nullptr;
 
     d->asyncdata = new dictAsyncRehashCtl(d, d->asyncdata);
 
@@ -454,7 +461,7 @@ void dictCompleteRehashAsync(dictAsyncRehashCtl *ctl, bool fFree) {
         }
     }
 
-    if (fUnlinked && !ctl->release) {
+    if (fUnlinked && !ctl->abondon) {
         if (d->ht[0].table != nullptr) {    // can be null if we're cleared during the rehash
             for (auto &wi : ctl->queue) {
                 // We need to remove it from the source hash table, and store it in the dest.
@@ -487,23 +494,10 @@ void dictCompleteRehashAsync(dictAsyncRehashCtl *ctl, bool fFree) {
     }
 
     if (fFree) {
-        while (ctl->deGCList != nullptr) {
+        d->type->asyncfree(ctl);
-            auto next = ctl->deGCList->next;
-            dictFreeKey(d, ctl->deGCList);
-            dictFreeVal(d, ctl->deGCList);
-            zfree(ctl->deGCList);
-            ctl->deGCList = next;
-        }
 
-        // Was the dictionary free'd while we were in flight?
+        // Remove our reference
-        if (ctl->release) {
+        dictRelease(d);
-            if (d->asyncdata != nullptr)
-                d->asyncdata->release = true;
-            else
-                dictRelease(d);
-        }
-
-        delete ctl;
     }
 }
 
@@ -514,6 +508,16 @@ long long timeInMilliseconds(void) {
     return (((long long)tv.tv_sec)*1000)+(tv.tv_usec/1000);
 }
 
+dictAsyncRehashCtl::~dictAsyncRehashCtl() {
+    while (deGCList != nullptr) {
+        auto next = deGCList->next;
+        dictFreeKey(dict, deGCList);
+        dictFreeVal(dict, deGCList);
+        zfree(deGCList);
+        deGCList = next;
+    }
+}
+
 /* Rehash in ms+"delta" milliseconds. The value of "delta" is larger 
  * than 0, and is smaller than 1 in most cases. The exact upper bound 
  * depends on the running time of dictRehash(d,100).*/
@@ -537,7 +541,7 @@ int dictRehashMilliseconds(dict *d, int ms) {
  * dictionary so that the hash table automatically migrates from H1 to H2
  * while it is actively used. */
 static void _dictRehashStep(dict *d) {
-    unsigned long iterators;
+    unsigned iterators;
     __atomic_load(&d->iterators, &iterators, __ATOMIC_RELAXED);
     if (iterators == 0) dictRehash(d,2);
 }
@@ -766,13 +770,11 @@ int _dictClear(dict *d, dictht *ht, void(callback)(void *)) {
 /* Clear & Release the hash table */
 void dictRelease(dict *d)
 {
-    if (d->asyncdata) {
+    if (__atomic_sub_fetch(&d->refcount, 1, __ATOMIC_ACQ_REL) == 0) {
-        d->asyncdata->release = true;
+        _dictClear(d,&d->ht[0],NULL);
-        return;
+        _dictClear(d,&d->ht[1],NULL);
+        zfree(d);
     }
-    _dictClear(d,&d->ht[0],NULL);
-    _dictClear(d,&d->ht[1],NULL);
-    zfree(d);
 }
 
 dictEntry *dictFindWithPrev(dict *d, const void *key, uint64_t h, dictEntry ***dePrevPtr, dictht **pht, bool fShallowCompare)
@@ -1460,7 +1462,7 @@ void dictGetStats(char *buf, size_t bufsize, dict *d) {
 
 void dictForceRehash(dict *d)
 {
-    unsigned long iterators;
+    unsigned iterators;
     __atomic_load(&d->iterators, &iterators, __ATOMIC_RELAXED);
     while (iterators == 0 && dictIsRehashing(d)) _dictRehashStep(d);
 }

src/dict.h

@@ -53,6 +53,7 @@ extern "C" {
 
 /* Unused arguments generate annoying warnings... */
 #define DICT_NOTUSED(V) ((void) V)
+struct dictAsyncRehashCtl;
 
 typedef struct dictEntry {
     void *key;
@@ -72,6 +73,7 @@ typedef struct dictType {
     int (*keyCompare)(void *privdata, const void *key1, const void *key2);
     void (*keyDestructor)(void *privdata, void *key);
     void (*valDestructor)(void *privdata, void *obj);
+    void (*asyncfree)(dictAsyncRehashCtl *);
 } dictType;
 
 /* This is our hash table structure. Every dictionary has two of this as we
@@ -98,13 +100,12 @@ struct dictAsyncRehashCtl {
     struct dict *dict = nullptr;
     std::vector<workItem> queue;
     size_t hashIdx = 0;
-    bool release = false;
     dictAsyncRehashCtl *next = nullptr;
     std::atomic<bool> done { false };
+    std::atomic<bool> abondon { false };
 
-    dictAsyncRehashCtl(struct dict *d, dictAsyncRehashCtl *next) : dict(d), next(next) {
+    dictAsyncRehashCtl(struct dict *d, dictAsyncRehashCtl *next);
-        queue.reserve(c_targetQueueSize);
+    ~dictAsyncRehashCtl();
-    }
 };
 #else
 struct  dictAsyncRehashCtl;
@@ -115,7 +116,8 @@ typedef struct dict {
     void *privdata;
     dictht ht[2];
     long rehashidx; /* rehashing not in progress if rehashidx == -1 */
-    unsigned long iterators; /* number of iterators currently running */
+    unsigned iterators; /* number of iterators currently running */
+    unsigned refcount;
     dictAsyncRehashCtl *asyncdata;
 } dict;
 

src/fastlock.cpp

@@ -433,7 +433,7 @@ extern "C" void fastlock_unlock(struct fastlock *lock)
         serverAssert(pidT >= 0);  // unlock after free
         int t = -1;
         __atomic_store(&lock->m_pidOwner, &t, __ATOMIC_RELEASE);
-        std::atomic_thread_fence(std::memory_order_release);
+        std::atomic_thread_fence(std::memory_order_acq_rel);
         ANNOTATE_RWLOCK_RELEASED(lock, true);
         uint16_t activeNew = __atomic_add_fetch(&lock->m_ticket.m_active, 1, __ATOMIC_RELEASE);  // on x86 the atomic is not required here, but ASM handles that case
 #ifdef __linux__

src/gc.h

@@ -29,6 +29,11 @@ class GarbageCollector
     };
 
 public:
+    ~GarbageCollector() {
+        // Silence TSAN errors
+        m_lock.lock();
+    }
+
     uint64_t startEpoch()
     {
         std::unique_lock<fastlock> lock(m_lock);
@@ -41,6 +46,7 @@ public:
     {
         std::unique_lock<fastlock> lock(m_lock);
         m_vecepochs.clear();
+        m_setepochOutstanding.clear();
     }
 
     void endEpoch(uint64_t epoch, bool fNoFree = false)

src/rdb.cpp

@@ -2370,21 +2370,6 @@ void rdbLoadProgressCallback(rio *r, const void *buf, size_t len) {
     }
 }
 
-class EvictionPolicyCleanup
-{
-    int oldpolicy;
-
-public:
-    EvictionPolicyCleanup() {
-        oldpolicy = g_pserver->maxmemory_policy;
-        g_pserver->maxmemory_policy = MAXMEMORY_ALLKEYS_RANDOM;
-    }
-
-    ~EvictionPolicyCleanup() {
-        g_pserver->maxmemory_policy = oldpolicy;
-    }
-};
-
 /* Load an RDB file from the rio stream 'rdb'. On success C_OK is returned,
  * otherwise C_ERR is returned and 'errno' is set accordingly. */
 int rdbLoadRio(rio *rdb, int rdbflags, rdbSaveInfo *rsi) {
@@ -2401,10 +2386,6 @@ int rdbLoadRio(rio *rdb, int rdbflags, rdbSaveInfo *rsi) {
     sds key = nullptr;
     bool fLastKeyExpired = false;
 
-    // If we're running flash we may evict during load.  We want a fast eviction function
-    //  because there isn't any difference in use times between keys anyways
-    EvictionPolicyCleanup ecleanup;
-
     for (int idb = 0; idb < cserver.dbnum; ++idb)
     {
         g_pserver->db[idb]->trackChanges(true, 1024);

src/sds.c

@@ -195,7 +195,7 @@ void sdsfree(const char *s) {
     if ((flags & SDS_TYPE_MASK) == SDS_TYPE_REFCOUNTED)
     {
         SDS_HDR_VAR_REFCOUNTED(s);
-        if (__atomic_fetch_sub(&sh->refcount, 1, __ATOMIC_RELAXED) > 1)
+        if (__atomic_fetch_sub(&sh->refcount, 1, __ATOMIC_ACQ_REL) > 1)
             return;
     }
     s_free((char*)s-sdsHdrSize(s[-1]));

src/server.cpp

@@ -1359,6 +1359,8 @@ uint64_t dictEncObjHash(const void *key) {
     }
 }
 
+void dictGCAsyncFree(dictAsyncRehashCtl *async);
+
 /* Generic hash table type where keys are Redis Objects, Values
  * dummy pointers. */
 dictType objectKeyPointerValueDictType = {
@@ -1407,8 +1409,9 @@ dictType dbDictType = {
     NULL,                       /* key dup */
     NULL,                       /* val dup */
     dictSdsKeyCompare,          /* key compare */
-    dictDbKeyDestructor,          /* key destructor */
+    dictDbKeyDestructor,        /* key destructor */
-    dictObjectDestructor   /* val destructor */
+    dictObjectDestructor,       /* val destructor */
+    dictGCAsyncFree             /* async free destructor */
 };
 
 /* db->pdict, keys are sds strings, vals are Redis objects. */
@@ -2424,18 +2427,6 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
         }
     }
 
-    run_with_period(100) {
-        bool fAnySnapshots = false;
-        for (int idb = 0; idb < cserver.dbnum && !fAnySnapshots; ++idb)
-            fAnySnapshots = fAnySnapshots || g_pserver->db[0]->FSnapshot();
-        if (fAnySnapshots)
-        {
-            g_pserver->asyncworkqueue->AddWorkFunction([]{
-                g_pserver->db[0]->consolidate_snapshot();
-            }, true /*HiPri*/);
-        }
-    }
-    
     /* Fire the cron loop modules event. */
     RedisModuleCronLoopV1 ei = {REDISMODULE_CRON_LOOP_VERSION,g_pserver->hz};
     moduleFireServerEvent(REDISMODULE_EVENT_CRON_LOOP,
@@ -3926,7 +3917,7 @@ void call(client *c, int flags) {
     dirty = g_pserver->dirty;
     incrementMvccTstamp();
     __atomic_load(&g_pserver->ustime, &start, __ATOMIC_SEQ_CST);
-    start = g_pserver->ustime;
+
     try {
         c->cmd->proc(c);
     } catch (robj_roptr o) {
@@ -5403,10 +5394,12 @@ sds genRedisInfoString(const char *section) {
             vkeys = g_pserver->db[j]->expireSize();
 
             // Adjust TTL by the current time
-            g_pserver->db[j]->avg_ttl -= (g_pserver->mstime - g_pserver->db[j]->last_expire_set);
+            mstime_t mstime;
+            __atomic_load(&g_pserver->mstime, &mstime, __ATOMIC_ACQUIRE);
+            g_pserver->db[j]->avg_ttl -= (mstime - g_pserver->db[j]->last_expire_set);
             if (g_pserver->db[j]->avg_ttl < 0)
                 g_pserver->db[j]->avg_ttl = 0;
-            g_pserver->db[j]->last_expire_set = g_pserver->mstime;
+            g_pserver->db[j]->last_expire_set = mstime;
             
             if (keys || vkeys) {
                 info = sdscatprintf(info,

src/server.h

@@ -1045,9 +1045,9 @@ class redisDbPersistentData
     friend class redisDbPersistentDataSnapshot;
 
 public:
+    redisDbPersistentData();
     virtual ~redisDbPersistentData();
 
-    redisDbPersistentData() = default;
     redisDbPersistentData(redisDbPersistentData &&) = default;
 
     size_t slots() const { return dictSlots(m_pdict); }
@@ -1130,8 +1130,6 @@ public:
     void endSnapshotAsync(const redisDbPersistentDataSnapshot *psnapshot);
     void restoreSnapshot(const redisDbPersistentDataSnapshot *psnapshot);
 
-    void consolidate_snapshot();
-
     bool FStorageProvider() { return m_spstorage != nullptr; }
     bool removeCachedValue(const char *key);
     void removeAllCachedValues();
@@ -1187,7 +1185,6 @@ private:
 
 protected:
     static void gcDisposeSnapshot(redisDbPersistentDataSnapshot *psnapshot);
-    void consolidate_children(redisDbPersistentData *pdbPrimary, bool fForce);
     bool freeTombstoneObjects(int depth);
 
 public:
@@ -1289,7 +1286,6 @@ struct redisDb : public redisDbPersistentDataSnapshot
     using redisDbPersistentData::createSnapshot;
     using redisDbPersistentData::endSnapshot;
     using redisDbPersistentData::restoreSnapshot;
-    using redisDbPersistentData::consolidate_snapshot;
     using redisDbPersistentData::removeAllCachedValues;
     using redisDbPersistentData::dictUnsafeKeyOnly;
     using redisDbPersistentData::resortExpire;

src/snapshot.cpp

@@ -26,6 +26,17 @@ public:
     std::vector<dictEntry*> vecde;
 };
 
+void discontinueAsyncRehash(dict *d) {
+    if (d->asyncdata != nullptr) {
+        auto adata = d->asyncdata;
+        while (adata != nullptr) {
+            adata->abondon = true;
+            adata = adata->next;
+        }
+        d->rehashidx = 0;
+    }
+}
+
 const redisDbPersistentDataSnapshot *redisDbPersistentData::createSnapshot(uint64_t mvccCheckpoint, bool fOptional)
 {
     serverAssert(GlobalLocksAcquired());
@@ -56,34 +67,6 @@ const redisDbPersistentDataSnapshot *redisDbPersistentData::createSnapshot(uint6
         }
     }
 
-    if (m_pdbSnapshot != nullptr && m_pdbSnapshot == m_pdbSnapshotASYNC && m_spdbSnapshotHOLDER->m_refCount == 1 && dictSize(m_pdictTombstone) < c_elementsSmallLimit)
-    {
-        serverLog(LL_WARNING, "Reusing old snapshot");
-        // is there an existing snapshot only owned by us?
-        
-        dictIterator *di = dictGetIterator(m_pdictTombstone);
-        dictEntry *de;
-        while ((de = dictNext(di)) != nullptr)
-        {
-            if (dictDelete(m_pdbSnapshot->m_pdict, dictGetKey(de)) != DICT_OK)
-                dictAdd(m_spdbSnapshotHOLDER->m_pdictTombstone, sdsdupshared((sds)dictGetKey(de)), nullptr);
-        }
-        dictReleaseIterator(di);
-
-        dictForceRehash(m_spdbSnapshotHOLDER->m_pdictTombstone);
-        dictMerge(m_pdbSnapshot->m_pdict, m_pdict);
-        dictEmpty(m_pdictTombstone, nullptr);
-        {
-        std::unique_lock<fastlock> ul(g_expireLock);
-        (*m_spdbSnapshotHOLDER->m_setexpire) = *m_setexpire;
-        }
-
-        m_pdbSnapshotASYNC = nullptr;
-        serverAssert(m_pdbSnapshot->m_pdict->iterators == 1);
-        serverAssert(m_spdbSnapshotHOLDER->m_refCount == 1);
-        return m_pdbSnapshot;
-    }
-
     // See if we have too many levels and can bail out of this to reduce load
     if (fOptional && (levels >= 6))
     {
@@ -95,14 +78,8 @@ const redisDbPersistentDataSnapshot *redisDbPersistentData::createSnapshot(uint6
     
     // We can't have async rehash modifying these.  Setting the asyncdata list to null
     //  will cause us to throw away the async work rather than modify the tables in flight
-    if (m_pdict->asyncdata != nullptr) {
+    discontinueAsyncRehash(m_pdict);
-        m_pdict->asyncdata = nullptr;
+    discontinueAsyncRehash(m_pdictTombstone);
-        m_pdict->rehashidx = 0;
-    }
-    if (m_pdictTombstone->asyncdata != nullptr) {
-        m_pdictTombstone->rehashidx = 0;
-        m_pdictTombstone->asyncdata = nullptr;
-    }
 
     spdb->m_fAllChanged = false;
     spdb->m_fTrackingChanges = 0;
@@ -125,7 +102,7 @@ const redisDbPersistentDataSnapshot *redisDbPersistentData::createSnapshot(uint6
     }
 
     if (dictIsRehashing(spdb->m_pdict) || dictIsRehashing(spdb->m_pdictTombstone)) {
-        serverLog(LL_NOTICE, "NOTICE: Suboptimal snapshot");
+        serverLog(LL_VERBOSE, "NOTICE: Suboptimal snapshot");
     }
 
     m_pdict = dictCreate(&dbDictType,this);
@@ -152,6 +129,7 @@ const redisDbPersistentDataSnapshot *redisDbPersistentData::createSnapshot(uint6
         m_pdbSnapshotASYNC = nullptr;
     }
 
+    std::atomic_thread_fence(std::memory_order_seq_cst);
     return m_pdbSnapshot;
 }
 
@@ -189,7 +167,7 @@ void redisDbPersistentData::recursiveFreeSnapshots(redisDbPersistentDataSnapshot
 
         //psnapshot->m_pdict->iterators--;
         psnapshot->m_spdbSnapshotHOLDER.release();
-        //psnapshot->m_pdbSnapshot = nullptr;
+        psnapshot->m_pdbSnapshot = nullptr;
         g_pserver->garbageCollector.enqueue(serverTL->gcEpoch, std::unique_ptr<redisDbPersistentDataSnapshot>(psnapshot));
         serverLog(LL_VERBOSE, "Garbage collected snapshot");
     }
@@ -275,7 +253,6 @@ void redisDbPersistentData::endSnapshotAsync(const redisDbPersistentDataSnapshot
         aeReleaseLock();
         return;
     }
-    const_cast<redisDbPersistentDataSnapshot*>(psnapshotT)->consolidate_children(this, true);
     
     // Final Cleanup
     aeAcquireLock(); latencyStartMonitor(latency);
@@ -347,6 +324,12 @@ bool redisDbPersistentDataSnapshot::freeTombstoneObjects(int depth)
 
     dictForceRehash(dictTombstoneNew);
     aeAcquireLock();
+    if (m_pdbSnapshot->m_pdict->asyncdata != nullptr) {
+        // In this case we use the asyncdata to free us, not our own lazy free
+        for (auto de : splazy->vecde)
+            dictFreeUnlinkedEntry(m_pdbSnapshot->m_pdict, de);
+        splazy->vecde.clear();
+    }
     dict *dT = m_pdbSnapshot->m_pdict;
     splazy->vecdictLazyFree.push_back(m_pdictTombstone);
     __atomic_store(&m_pdictTombstone, &dictTombstoneNew, __ATOMIC_RELEASE);
@@ -421,7 +404,7 @@ void redisDbPersistentData::endSnapshot(const redisDbPersistentDataSnapshot *psn
 #ifdef CHECKED_BUILD
             serverAssert(m_spdbSnapshotHOLDER->m_pdbSnapshot->find_cached_threadsafe((const char*)dictGetKey(de)) != nullptr);
 #endif
-            dictAdd(m_spdbSnapshotHOLDER->m_pdictTombstone, sdsdupshared((sds)dictGetKey(de)), nullptr);
+            dictAdd(m_spdbSnapshotHOLDER->m_pdictTombstone, sdsdupshared((sds)dictGetKey(de)), dictGetVal(de));
             continue;
         }
         else if (deSnapshot == nullptr)
@@ -431,8 +414,14 @@ void redisDbPersistentData::endSnapshot(const redisDbPersistentDataSnapshot *psn
         }
         
         // Delete the object from the source dict, we don't use dictDelete to avoid a second search
-        splazy->vecde.push_back(deSnapshot);
+        *dePrev = deSnapshot->next; // Unlink it first
-        *dePrev = deSnapshot->next;
+        if (deSnapshot != nullptr) {
+            if (m_spdbSnapshotHOLDER->m_pdict->asyncdata != nullptr) {
+                dictFreeUnlinkedEntry(m_spdbSnapshotHOLDER->m_pdict, deSnapshot);
+            } else {
+                splazy->vecde.push_back(deSnapshot);
+            }
+        }
         ht->used--;
     }
 
@@ -454,12 +443,12 @@ void redisDbPersistentData::endSnapshot(const redisDbPersistentDataSnapshot *psn
     if (m_pdbSnapshot != nullptr && m_spdbSnapshotHOLDER->m_pdbSnapshot != nullptr)
     {
         m_pdbSnapshot = m_spdbSnapshotHOLDER->m_pdbSnapshot;
-        m_spdbSnapshotHOLDER->m_pdbSnapshot = nullptr;
     }
     else
     {
         m_pdbSnapshot = nullptr;
     }
+    m_spdbSnapshotHOLDER->m_pdbSnapshot = nullptr;
 
     // Fixup the about to free'd snapshots iterator count so the dtor doesn't complain
     if (m_refCount)
@@ -663,111 +652,23 @@ int redisDbPersistentDataSnapshot::snapshot_depth() const
     return 0;
 }
 
-
-void redisDbPersistentData::consolidate_snapshot()
-{
-    aeAcquireLock();
-    auto psnapshot = (m_pdbSnapshot != nullptr) ? m_spdbSnapshotHOLDER.get() : nullptr;
-    if (psnapshot == nullptr || psnapshot->snapshot_depth() == 0)
-    {
-        aeReleaseLock();
-        return;
-    }
-
-    psnapshot->m_refCount++;    // ensure it's not free'd
-    aeReleaseLock();
-    psnapshot->consolidate_children(this, false /* fForce */);
-    aeAcquireLock();
-    endSnapshot(psnapshot);
-    aeReleaseLock();
-}
-
-// only call this on the "real" database to consolidate the first child
-void redisDbPersistentDataSnapshot::consolidate_children(redisDbPersistentData *pdbPrimary, bool fForce)
-{
-    std::unique_lock<fastlock> lock(s_lock, std::defer_lock);
-    if (!lock.try_lock())
-        return; // this is a best effort function
-
-    if (!fForce && snapshot_depth() < 2)
-        return;
-
-    auto spdb = std::unique_ptr<redisDbPersistentDataSnapshot>(new (MALLOC_LOCAL) redisDbPersistentDataSnapshot());
-    spdb->initialize();
-    dictExpand(spdb->m_pdict, m_pdbSnapshot->size());
-
-    volatile size_t skipped = 0;
-    m_pdbSnapshot->iterate_threadsafe([&](const char *key, robj_roptr o) {
-        if (o != nullptr || !m_spstorage) {
-            dictAdd(spdb->m_pdict, sdsdupshared(key), o.unsafe_robjcast());
-            if (o != nullptr) {
-                incrRefCount(o);
-            }
-        } else {
-            ++skipped;
-        }
-        return true;
-    }, true /*fKeyOnly*/, true /*fCacheOnly*/);
-    spdb->m_spstorage = m_pdbSnapshot->m_spstorage;
-    {
-    std::unique_lock<fastlock> ul(g_expireLock);
-    delete spdb->m_setexpire;
-    spdb->m_setexpire = new (MALLOC_LOCAL) expireset(*m_pdbSnapshot->m_setexpire);
-    }
-
-    spdb->m_pdict->iterators++;
-
-    if (m_spstorage) {
-        serverAssert(spdb->size() == m_pdbSnapshot->size());
-    } else {
-        serverAssert((spdb->size()+skipped) == m_pdbSnapshot->size());
-    }
-
-    // Now wire us in (Acquire the LOCK)
-    AeLocker locker;
-    locker.arm(nullptr);
-
-    int depth = 0;
-    redisDbPersistentDataSnapshot *psnapshotT = pdbPrimary->m_spdbSnapshotHOLDER.get();
-    while (psnapshotT != nullptr)
-    {
-        ++depth;
-        if (psnapshotT == this)
-            break;
-        psnapshotT = psnapshotT->m_spdbSnapshotHOLDER.get();
-    }
-    if (psnapshotT != this)
-    {
-        locker.disarm();    // don't run spdb's dtor in the lock
-        return; // we were unlinked and this was a waste of time
-    }
-
-    serverLog(LL_VERBOSE, "cleaned %d snapshots", snapshot_depth()-1);
-    spdb->m_refCount = depth;
-    // Drop our refs from this snapshot and its children
-    psnapshotT = this;
-    std::vector<redisDbPersistentDataSnapshot*> vecT;
-    while ((psnapshotT = psnapshotT->m_spdbSnapshotHOLDER.get()) != nullptr)
-    {
-        vecT.push_back(psnapshotT);
-    }
-    for (auto itr = vecT.rbegin(); itr != vecT.rend(); ++itr)
-    {
-        psnapshotT = *itr;
-        psnapshotT->m_refCount -= (depth-1);    // -1 because dispose will sub another
-        gcDisposeSnapshot(psnapshotT);
-    }
-    std::atomic_thread_fence(std::memory_order_seq_cst);
-    m_spdbSnapshotHOLDER.release(); // GC has responsibility for it now
-    m_spdbSnapshotHOLDER = std::move(spdb);
-    const redisDbPersistentDataSnapshot *ptrT = m_spdbSnapshotHOLDER.get();
-    __atomic_store(&m_pdbSnapshot, &ptrT, __ATOMIC_SEQ_CST);
-    locker.disarm();    // ensure we're not locked for any dtors
-}
-
 bool redisDbPersistentDataSnapshot::FStale() const
 {
     // 0.5 seconds considered stale;
     static const uint64_t msStale = 500;
     return ((getMvccTstamp() - m_mvccCheckpoint) >> MVCC_MS_SHIFT) >= msStale;
+}
+
+void dictGCAsyncFree(dictAsyncRehashCtl *async) {
+    if (async->deGCList != nullptr && serverTL != nullptr && !serverTL->gcEpoch.isReset()) {
+        auto splazy = std::make_unique<LazyFree>();
+        auto *de = async->deGCList;
+        while (de != nullptr) {
+            splazy->vecde.push_back(de);
+            de = de->next;
+        }
+        async->deGCList = nullptr;
+        g_pserver->garbageCollector.enqueue(serverTL->gcEpoch, std::move(splazy));
+    }
+    delete async;
 }