Redis 2.6.4

[redis.git] / src / db.c

diff --git a/src/db.c b/src/db.c
index e1e82cb22fcd30540f97e2846b7bb020d6eb3531..59479574a91658f4003f84bf2bb0661a8bf9dcd3 100644 (file)
--- a/src/db.c
+++ b/src/db.c
@@ -1,6 +1,39 @@
+/*
+ * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+

 #include "redis.h"
 
 #include <signal.h>
 #include "redis.h"
 
 #include <signal.h>

+#include <ctype.h>
+
+void SlotToKeyAdd(robj *key);
+void SlotToKeyDel(robj *key);

 
 /*-----------------------------------------------------------------------------
  * C-level DB API
 
 /*-----------------------------------------------------------------------------
  * C-level DB API


@@ -9,30 +42,13 @@
 robj *lookupKey(redisDb *db, robj *key) {
     dictEntry *de = dictFind(db->dict,key->ptr);
     if (de) {
 robj *lookupKey(redisDb *db, robj *key) {
     dictEntry *de = dictFind(db->dict,key->ptr);
     if (de) {

-        robj *val = dictGetEntryVal(de);
-
-        if (server.vm_enabled) {
-            if (val->storage == REDIS_VM_MEMORY ||
-                val->storage == REDIS_VM_SWAPPING)
-            {
-                /* If we were swapping the object out, cancel the operation */
-                if (val->storage == REDIS_VM_SWAPPING)
-                    vmCancelThreadedIOJob(val);
-                /* Update the access time for the aging algorithm. */
-                val->lru = server.lruclock;
-            } else {
-                int notify = (val->storage == REDIS_VM_LOADING);
-
-                /* Our value was swapped on disk. Bring it at home. */
-                redisAssert(val->type == REDIS_VMPOINTER);
-                val = vmLoadObject(val);
-                dictGetEntryVal(de) = val;
-
-                /* Clients blocked by the VM subsystem may be waiting for
-                 * this key... */
-                if (notify) handleClientsBlockedOnSwappedKey(db,key);
-            }
-        }
+        robj *val = dictGetVal(de);
+
+        /* Update the access time for the aging algorithm.
+         * Don't do it if we have a saving child, as this will trigger
+         * a copy on write madness. */
+        if (server.rdb_child_pid == -1 && server.aof_child_pid == -1)
+            val->lru = server.lruclock;

         return val;
     } else {
         return NULL;
         return val;
     } else {
         return NULL;


@@ -40,13 +56,19 @@ robj *lookupKey(redisDb *db, robj *key) {
 }
 
 robj *lookupKeyRead(redisDb *db, robj *key) {
 }
 
 robj *lookupKeyRead(redisDb *db, robj *key) {

+    robj *val;
+

     expireIfNeeded(db,key);
     expireIfNeeded(db,key);

-    return lookupKey(db,key);
+    val = lookupKey(db,key);
+    if (val == NULL)
+        server.stat_keyspace_misses++;
+    else
+        server.stat_keyspace_hits++;
+    return val;

 }
 
 robj *lookupKeyWrite(redisDb *db, robj *key) {
 }
 
 robj *lookupKeyWrite(redisDb *db, robj *key) {

-    deleteIfVolatile(db,key);
-    touchWatchedKey(db,key);
+    expireIfNeeded(db,key);

     return lookupKey(db,key);
 }
 
     return lookupKey(db,key);
 }
 


@@ -62,34 +84,44 @@ robj *lookupKeyWriteOrReply(redisClient *c, robj *key, robj *reply) {
     return o;
 }
 
     return o;
 }
 

-/* Add the key to the DB. If the key already exists REDIS_ERR is returned,
- * otherwise REDIS_OK is returned, and the caller should increment the
- * refcount of 'val'. */
-int dbAdd(redisDb *db, robj *key, robj *val) {
-    /* Perform a lookup before adding the key, as we need to copy the
-     * key value. */
-    if (dictFind(db->dict, key->ptr) != NULL) {
-        return REDIS_ERR;
-    } else {
-        sds copy = sdsdup(key->ptr);
-        dictAdd(db->dict, copy, val);
-        return REDIS_OK;
-    }
+/* Add the key to the DB. It's up to the caller to increment the reference
+ * counte of the value if needed.
+ *
+ * The program is aborted if the key already exists. */
+void dbAdd(redisDb *db, robj *key, robj *val) {
+    sds copy = sdsdup(key->ptr);
+    int retval = dictAdd(db->dict, copy, val);
+
+    redisAssertWithInfo(NULL,key,retval == REDIS_OK);
+ }
+
+/* Overwrite an existing key with a new value. Incrementing the reference
+ * count of the new value is up to the caller.
+ * This function does not modify the expire time of the existing key.
+ *
+ * The program is aborted if the key was not already present. */
+void dbOverwrite(redisDb *db, robj *key, robj *val) {
+    struct dictEntry *de = dictFind(db->dict,key->ptr);
+    
+    redisAssertWithInfo(NULL,key,de != NULL);
+    dictReplace(db->dict, key->ptr, val);

 }
 
 }
 

-/* If the key does not exist, this is just like dbAdd(). Otherwise
- * the value associated to the key is replaced with the new one.
+/* High level Set operation. This function can be used in order to set
+ * a key, whatever it was existing or not, to a new object.

  *
  *

- * On update (key already existed) 0 is returned. Otherwise 1. */
-int dbReplace(redisDb *db, robj *key, robj *val) {
-    if (dictFind(db->dict,key->ptr) == NULL) {
-        sds copy = sdsdup(key->ptr);
-        dictAdd(db->dict, copy, val);
-        return 1;
+ * 1) The ref count of the value object is incremented.
+ * 2) clients WATCHing for the destination key notified.
+ * 3) The expire time of the key is reset (the key is made persistent). */
+void setKey(redisDb *db, robj *key, robj *val) {
+    if (lookupKeyWrite(db,key) == NULL) {
+        dbAdd(db,key,val);

     } else {
     } else {

-        dictReplace(db->dict, key->ptr, val);
-        return 0;
+        dbOverwrite(db,key,val);

     }
     }

+    incrRefCount(val);
+    removeExpire(db,key);
+    signalModifiedKey(db,key);

 }
 
 int dbExists(redisDb *db, robj *key) {
 }
 
 int dbExists(redisDb *db, robj *key) {


@@ -110,7 +142,7 @@ robj *dbRandomKey(redisDb *db) {
         de = dictGetRandomKey(db->dict);
         if (de == NULL) return NULL;
 
         de = dictGetRandomKey(db->dict);
         if (de == NULL) return NULL;
 

-        key = dictGetEntryKey(de);
+        key = dictGetKey(de);

         keyobj = createStringObject(key,sdslen(key));
         if (dictFind(db->expires,key)) {
             if (expireIfNeeded(db,keyobj)) {
         keyobj = createStringObject(key,sdslen(key));
         if (dictFind(db->expires,key)) {
             if (expireIfNeeded(db,keyobj)) {


@@ -127,10 +159,13 @@ int dbDelete(redisDb *db, robj *key) {
     /* Deleting an entry from the expires dict will not free the sds of
      * the key, because it is shared with the main dictionary. */
     if (dictSize(db->expires) > 0) dictDelete(db->expires,key->ptr);
     /* Deleting an entry from the expires dict will not free the sds of
      * the key, because it is shared with the main dictionary. */
     if (dictSize(db->expires) > 0) dictDelete(db->expires,key->ptr);

-    return dictDelete(db->dict,key->ptr) == DICT_OK;
+    if (dictDelete(db->dict,key->ptr) == DICT_OK) {
+        return 1;
+    } else {
+        return 0;
+    }

 }
 
 }
 

-/* Empty the whole database */

 long long emptyDb() {
     int j;
     long long removed = 0;
 long long emptyDb() {
     int j;
     long long removed = 0;


@@ -150,27 +185,50 @@ int selectDb(redisClient *c, int id) {
     return REDIS_OK;
 }
 
     return REDIS_OK;
 }
 

+/*-----------------------------------------------------------------------------
+ * Hooks for key space changes.
+ *
+ * Every time a key in the database is modified the function
+ * signalModifiedKey() is called.
+ *
+ * Every time a DB is flushed the function signalFlushDb() is called.
+ *----------------------------------------------------------------------------*/
+
+void signalModifiedKey(redisDb *db, robj *key) {
+    touchWatchedKey(db,key);
+}
+
+void signalFlushedDb(int dbid) {
+    touchWatchedKeysOnFlush(dbid);
+}
+

 /*-----------------------------------------------------------------------------
  * Type agnostic commands operating on the key space
  *----------------------------------------------------------------------------*/
 
 void flushdbCommand(redisClient *c) {
     server.dirty += dictSize(c->db->dict);
 /*-----------------------------------------------------------------------------
  * Type agnostic commands operating on the key space
  *----------------------------------------------------------------------------*/
 
 void flushdbCommand(redisClient *c) {
     server.dirty += dictSize(c->db->dict);

-    touchWatchedKeysOnFlush(c->db->id);
+    signalFlushedDb(c->db->id);

     dictEmpty(c->db->dict);
     dictEmpty(c->db->expires);
     addReply(c,shared.ok);
 }
 
 void flushallCommand(redisClient *c) {
     dictEmpty(c->db->dict);
     dictEmpty(c->db->expires);
     addReply(c,shared.ok);
 }
 
 void flushallCommand(redisClient *c) {

-    touchWatchedKeysOnFlush(-1);
+    signalFlushedDb(-1);

     server.dirty += emptyDb();
     addReply(c,shared.ok);
     server.dirty += emptyDb();
     addReply(c,shared.ok);

-    if (server.bgsavechildpid != -1) {
-        kill(server.bgsavechildpid,SIGKILL);
-        rdbRemoveTempFile(server.bgsavechildpid);
+    if (server.rdb_child_pid != -1) {
+        kill(server.rdb_child_pid,SIGKILL);
+        rdbRemoveTempFile(server.rdb_child_pid);
+    }
+    if (server.saveparamslen > 0) {
+        /* Normally rdbSave() will reset dirty, but we don't want this here
+         * as otherwise FLUSHALL will not be replicated nor put into the AOF. */
+        int saved_dirty = server.dirty;
+        rdbSave(server.rdb_filename);
+        server.dirty = saved_dirty;

     }
     }

-    rdbSave(server.dbfilename);

     server.dirty++;
 }
 
     server.dirty++;
 }
 


@@ -179,7 +237,7 @@ void delCommand(redisClient *c) {
 
     for (j = 1; j < c->argc; j++) {
         if (dbDelete(c->db,c->argv[j])) {
 
     for (j = 1; j < c->argc; j++) {
         if (dbDelete(c->db,c->argv[j])) {

-            touchWatchedKey(c->db,c->argv[j]);
+            signalModifiedKey(c->db,c->argv[j]);

             server.dirty++;
             deleted++;
         }
             server.dirty++;
             deleted++;
         }


@@ -197,10 +255,14 @@ void existsCommand(redisClient *c) {
 }
 
 void selectCommand(redisClient *c) {
 }
 
 void selectCommand(redisClient *c) {

-    int id = atoi(c->argv[1]->ptr);
+    long id;
+
+    if (getLongFromObjectOrReply(c, c->argv[1], &id,
+        "invalid DB index") != REDIS_OK)
+        return;

 
     if (selectDb(c,id) == REDIS_ERR) {
 
     if (selectDb(c,id) == REDIS_ERR) {

-        addReplySds(c,sdsnew("-ERR invalid DB index\r\n"));
+        addReplyError(c,"invalid DB index");

     } else {
         addReply(c,shared.ok);
     }
     } else {
         addReply(c,shared.ok);
     }


@@ -222,19 +284,17 @@ void keysCommand(redisClient *c) {
     dictIterator *di;
     dictEntry *de;
     sds pattern = c->argv[1]->ptr;
     dictIterator *di;
     dictEntry *de;
     sds pattern = c->argv[1]->ptr;

-    int plen = sdslen(pattern);
+    int plen = sdslen(pattern), allkeys;

     unsigned long numkeys = 0;
     unsigned long numkeys = 0;

-    robj *lenobj = createObject(REDIS_STRING,NULL);
+    void *replylen = addDeferredMultiBulkLength(c);

 
 

-    di = dictGetIterator(c->db->dict);
-    addReply(c,lenobj);
-    decrRefCount(lenobj);
+    di = dictGetSafeIterator(c->db->dict);
+    allkeys = (pattern[0] == '*' && pattern[1] == '\0');

     while((de = dictNext(di)) != NULL) {
     while((de = dictNext(di)) != NULL) {

-        sds key = dictGetEntryKey(de);
+        sds key = dictGetKey(de);

         robj *keyobj;
 
         robj *keyobj;
 

-        if ((pattern[0] == '*' && pattern[1] == '\0') ||
-            stringmatchlen(pattern,plen,key,sdslen(key),0)) {
+        if (allkeys || stringmatchlen(pattern,plen,key,sdslen(key),0)) {

             keyobj = createStringObject(key,sdslen(key));
             if (expireIfNeeded(c->db,keyobj) == 0) {
                 addReplyBulk(c,keyobj);
             keyobj = createStringObject(key,sdslen(key));
             if (expireIfNeeded(c->db,keyobj) == 0) {
                 addReplyBulk(c,keyobj);


@@ -244,17 +304,15 @@ void keysCommand(redisClient *c) {
         }
     }
     dictReleaseIterator(di);
         }
     }
     dictReleaseIterator(di);

-    lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n",numkeys);
+    setDeferredMultiBulkLength(c,replylen,numkeys);

 }
 
 void dbsizeCommand(redisClient *c) {
 }
 
 void dbsizeCommand(redisClient *c) {

-    addReplySds(c,
-        sdscatprintf(sdsempty(),":%lu\r\n",dictSize(c->db->dict)));
+    addReplyLongLong(c,dictSize(c->db->dict));

 }
 
 void lastsaveCommand(redisClient *c) {
 }
 
 void lastsaveCommand(redisClient *c) {

-    addReplySds(c,
-        sdscatprintf(sdsempty(),":%lu\r\n",server.lastsave));
+    addReplyLongLong(c,server.lastsave);

 }
 
 void typeCommand(redisClient *c) {
 }
 
 void typeCommand(redisClient *c) {


@@ -263,54 +321,43 @@ void typeCommand(redisClient *c) {
 
     o = lookupKeyRead(c->db,c->argv[1]);
     if (o == NULL) {
 
     o = lookupKeyRead(c->db,c->argv[1]);
     if (o == NULL) {

-        type = "+none";
+        type = "none";

     } else {
         switch(o->type) {
     } else {
         switch(o->type) {

-        case REDIS_STRING: type = "+string"; break;
-        case REDIS_LIST: type = "+list"; break;
-        case REDIS_SET: type = "+set"; break;
-        case REDIS_ZSET: type = "+zset"; break;
-        case REDIS_HASH: type = "+hash"; break;
-        default: type = "+unknown"; break;
+        case REDIS_STRING: type = "string"; break;
+        case REDIS_LIST: type = "list"; break;
+        case REDIS_SET: type = "set"; break;
+        case REDIS_ZSET: type = "zset"; break;
+        case REDIS_HASH: type = "hash"; break;
+        default: type = "unknown"; break;

         }
     }
         }
     }

-    addReplySds(c,sdsnew(type));
-    addReply(c,shared.crlf);
+    addReplyStatus(c,type);

 }
 
 }
 

-void saveCommand(redisClient *c) {
-    if (server.bgsavechildpid != -1) {
-        addReplySds(c,sdsnew("-ERR background save in progress\r\n"));
-        return;
-    }
-    if (rdbSave(server.dbfilename) == REDIS_OK) {
-        addReply(c,shared.ok);
-    } else {
-        addReply(c,shared.err);
-    }
-}
+void shutdownCommand(redisClient *c) {
+    int flags = 0;

 
 

-void bgsaveCommand(redisClient *c) {
-    if (server.bgsavechildpid != -1) {
-        addReplySds(c,sdsnew("-ERR background save already in progress\r\n"));
+    if (c->argc > 2) {
+        addReply(c,shared.syntaxerr);

         return;
         return;

+    } else if (c->argc == 2) {
+        if (!strcasecmp(c->argv[1]->ptr,"nosave")) {
+            flags |= REDIS_SHUTDOWN_NOSAVE;
+        } else if (!strcasecmp(c->argv[1]->ptr,"save")) {
+            flags |= REDIS_SHUTDOWN_SAVE;
+        } else {
+            addReply(c,shared.syntaxerr);
+            return;
+        }

     }
     }

-    if (rdbSaveBackground(server.dbfilename) == REDIS_OK) {
-        char *status = "+Background saving started\r\n";
-        addReplySds(c,sdsnew(status));
-    } else {
-        addReply(c,shared.err);
-    }
-}
-
-void shutdownCommand(redisClient *c) {
-    if (prepareForShutdown() == REDIS_OK)
-        exit(0);
-    addReplySds(c, sdsnew("-ERR Errors trying to SHUTDOWN. Check logs.\r\n"));
+    if (prepareForShutdown(flags) == REDIS_OK) exit(0);
+    addReplyError(c,"Errors trying to SHUTDOWN. Check logs.");

 }
 
 void renameGenericCommand(redisClient *c, int nx) {
     robj *o;
 }
 
 void renameGenericCommand(redisClient *c, int nx) {
     robj *o;

+    long long expire;

 
     /* To use the same key as src and dst is probably an error */
     if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
 
     /* To use the same key as src and dst is probably an error */
     if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {


@@ -322,17 +369,21 @@ void renameGenericCommand(redisClient *c, int nx) {
         return;
 
     incrRefCount(o);
         return;
 
     incrRefCount(o);

-    deleteIfVolatile(c->db,c->argv[2]);
-    if (dbAdd(c->db,c->argv[2],o) == REDIS_ERR) {
+    expire = getExpire(c->db,c->argv[1]);
+    if (lookupKeyWrite(c->db,c->argv[2]) != NULL) {

         if (nx) {
             decrRefCount(o);
             addReply(c,shared.czero);
             return;
         }
         if (nx) {
             decrRefCount(o);
             addReply(c,shared.czero);
             return;
         }

-        dbReplace(c->db,c->argv[2],o);
+        /* Overwrite: delete the old key before creating the new one with the same name. */
+        dbDelete(c->db,c->argv[2]);

     }
     }

+    dbAdd(c->db,c->argv[2],o);
+    if (expire != -1) setExpire(c->db,c->argv[2],expire);

     dbDelete(c->db,c->argv[1]);
     dbDelete(c->db,c->argv[1]);

-    touchWatchedKey(c->db,c->argv[2]);
+    signalModifiedKey(c->db,c->argv[1]);
+    signalModifiedKey(c->db,c->argv[2]);

     server.dirty++;
     addReply(c,nx ? shared.cone : shared.ok);
 }
     server.dirty++;
     addReply(c,nx ? shared.cone : shared.ok);
 }


@@ -374,12 +425,12 @@ void moveCommand(redisClient *c) {
         return;
     }
 
         return;
     }
 

-    /* Try to add the element to the target DB */
-    deleteIfVolatile(dst,c->argv[1]);
-    if (dbAdd(dst,c->argv[1],o) == REDIS_ERR) {
+    /* Return zero if the key already exists in the target DB */
+    if (lookupKeyWrite(dst,c->argv[1]) != NULL) {

         addReply(c,shared.czero);
         return;
     }
         addReply(c,shared.czero);
         return;
     }

+    dbAdd(dst,c->argv[1],o);

     incrRefCount(o);
 
     /* OK! key moved, free the entry in the source DB */
     incrRefCount(o);
 
     /* OK! key moved, free the entry in the source DB */


@@ -395,29 +446,23 @@ void moveCommand(redisClient *c) {
 int removeExpire(redisDb *db, robj *key) {
     /* An expire may only be removed if there is a corresponding entry in the
      * main dict. Otherwise, the key will never be freed. */
 int removeExpire(redisDb *db, robj *key) {
     /* An expire may only be removed if there is a corresponding entry in the
      * main dict. Otherwise, the key will never be freed. */

-    redisAssert(dictFind(db->dict,key->ptr) != NULL);
-    if (dictDelete(db->expires,key->ptr) == DICT_OK) {
-        return 1;
-    } else {
-        return 0;
-    }
+    redisAssertWithInfo(NULL,key,dictFind(db->dict,key->ptr) != NULL);
+    return dictDelete(db->expires,key->ptr) == DICT_OK;

 }
 
 }
 

-int setExpire(redisDb *db, robj *key, time_t when) {
-    dictEntry *de;
+void setExpire(redisDb *db, robj *key, long long when) {
+    dictEntry *kde, *de;

 
     /* Reuse the sds from the main dict in the expire dict */
 
     /* Reuse the sds from the main dict in the expire dict */

-    redisAssert((de = dictFind(db->dict,key->ptr)) != NULL);
-    if (dictAdd(db->expires,dictGetEntryKey(de),(void*)when) == DICT_ERR) {
-        return 0;
-    } else {
-        return 1;
-    }
+    kde = dictFind(db->dict,key->ptr);
+    redisAssertWithInfo(NULL,key,kde != NULL);
+    de = dictReplaceRaw(db->expires,dictGetKey(kde));
+    dictSetSignedIntegerVal(de,when);

 }
 
 /* Return the expire time of the specified key, or -1 if no expire
  * is associated with this key (i.e. the key is non volatile) */
 }
 
 /* Return the expire time of the specified key, or -1 if no expire
  * is associated with this key (i.e. the key is non volatile) */

-time_t getExpire(redisDb *db, robj *key) {
+long long getExpire(redisDb *db, robj *key) {

     dictEntry *de;
 
     /* No expire? return ASAP */
     dictEntry *de;
 
     /* No expire? return ASAP */


@@ -426,29 +471,60 @@ time_t getExpire(redisDb *db, robj *key) {
 
     /* The entry was found in the expire dict, this means it should also
      * be present in the main dict (safety check). */
 
     /* The entry was found in the expire dict, this means it should also
      * be present in the main dict (safety check). */

-    redisAssert(dictFind(db->dict,key->ptr) != NULL);
-    return (time_t) dictGetEntryVal(de);
+    redisAssertWithInfo(NULL,key,dictFind(db->dict,key->ptr) != NULL);
+    return dictGetSignedIntegerVal(de);

 }
 
 }
 

-int expireIfNeeded(redisDb *db, robj *key) {
-    time_t when = getExpire(db,key);
-    if (when < 0) return 0;
+/* Propagate expires into slaves and the AOF file.
+ * When a key expires in the master, a DEL operation for this key is sent
+ * to all the slaves and the AOF file if enabled.
+ *
+ * This way the key expiry is centralized in one place, and since both
+ * AOF and the master->slave link guarantee operation ordering, everything
+ * will be consistent even if we allow write operations against expiring
+ * keys. */
+void propagateExpire(redisDb *db, robj *key) {
+    robj *argv[2];

 
 

-    /* Return when this key has not expired */
-    if (time(NULL) <= when) return 0;
+    argv[0] = shared.del;
+    argv[1] = key;
+    incrRefCount(argv[0]);
+    incrRefCount(argv[1]);

 
 

-    /* Delete the key */
-    server.stat_expiredkeys++;
-    server.dirty++;
-    return dbDelete(db,key);
+    if (server.aof_state != REDIS_AOF_OFF)
+        feedAppendOnlyFile(server.delCommand,db->id,argv,2);
+    if (listLength(server.slaves))
+        replicationFeedSlaves(server.slaves,db->id,argv,2);
+
+    decrRefCount(argv[0]);
+    decrRefCount(argv[1]);

 }
 
 }
 

-int deleteIfVolatile(redisDb *db, robj *key) {
-    if (getExpire(db,key) < 0) return 0;
+int expireIfNeeded(redisDb *db, robj *key) {
+    long long when = getExpire(db,key);
+
+    if (when < 0) return 0; /* No expire for this key */
+
+    /* Don't expire anything while loading. It will be done later. */
+    if (server.loading) return 0;
+
+    /* If we are running in the context of a slave, return ASAP:
+     * the slave key expiration is controlled by the master that will
+     * send us synthesized DEL operations for expired keys.
+     *
+     * Still we try to return the right information to the caller, 
+     * that is, 0 if we think the key should be still valid, 1 if
+     * we think the key is expired at this time. */
+    if (server.masterhost != NULL) {
+        return mstime() > when;
+    }
+
+    /* Return when this key has not expired */
+    if (mstime() <= when) return 0;

 
     /* Delete the key */
     server.stat_expiredkeys++;
 
     /* Delete the key */
     server.stat_expiredkeys++;

-    server.dirty++;
+    propagateExpire(db,key);

     return dbDelete(db,key);
 }
 
     return dbDelete(db,key);
 }
 


@@ -456,53 +532,181 @@ int deleteIfVolatile(redisDb *db, robj *key) {
  * Expires Commands
  *----------------------------------------------------------------------------*/
 
  * Expires Commands
  *----------------------------------------------------------------------------*/
 

-void expireGenericCommand(redisClient *c, robj *key, robj *param, long offset) {
+/* This is the generic command implementation for EXPIRE, PEXPIRE, EXPIREAT
+ * and PEXPIREAT. Because the commad second argument may be relative or absolute
+ * the "basetime" argument is used to signal what the base time is (either 0
+ * for *AT variants of the command, or the current time for relative expires).
+ *
+ * unit is either UNIT_SECONDS or UNIT_MILLISECONDS, and is only used for
+ * the argv[2] parameter. The basetime is always specified in milliesconds. */
+void expireGenericCommand(redisClient *c, long long basetime, int unit) {

     dictEntry *de;
     dictEntry *de;

-    time_t seconds;
+    robj *key = c->argv[1], *param = c->argv[2];
+    long long when; /* unix time in milliseconds when the key will expire. */

 
 

-    if (getLongFromObjectOrReply(c, param, &seconds, NULL) != REDIS_OK) return;
+    if (getLongLongFromObjectOrReply(c, param, &when, NULL) != REDIS_OK)
+        return;

 
 

-    seconds -= offset;
+    if (unit == UNIT_SECONDS) when *= 1000;
+    when += basetime;

 
     de = dictFind(c->db->dict,key->ptr);
     if (de == NULL) {
         addReply(c,shared.czero);
         return;
     }
 
     de = dictFind(c->db->dict,key->ptr);
     if (de == NULL) {
         addReply(c,shared.czero);
         return;
     }

-    if (seconds <= 0) {
-        if (dbDelete(c->db,key)) server.dirty++;
+    /* EXPIRE with negative TTL, or EXPIREAT with a timestamp into the past
+     * should never be executed as a DEL when load the AOF or in the context
+     * of a slave instance.
+     *
+     * Instead we take the other branch of the IF statement setting an expire
+     * (possibly in the past) and wait for an explicit DEL from the master. */
+    if (when <= mstime() && !server.loading && !server.masterhost) {
+        robj *aux;
+
+        redisAssertWithInfo(c,key,dbDelete(c->db,key));
+        server.dirty++;
+
+        /* Replicate/AOF this as an explicit DEL. */
+        aux = createStringObject("DEL",3);
+        rewriteClientCommandVector(c,2,aux,key);
+        decrRefCount(aux);
+        signalModifiedKey(c->db,key);

         addReply(c, shared.cone);
         return;
     } else {
         addReply(c, shared.cone);
         return;
     } else {

-        time_t when = time(NULL)+seconds;
-        if (setExpire(c->db,key,when)) {
-            addReply(c,shared.cone);
-            server.dirty++;
-        } else {
-            addReply(c,shared.czero);
-        }
+        setExpire(c->db,key,when);
+        addReply(c,shared.cone);
+        signalModifiedKey(c->db,key);
+        server.dirty++;

         return;
     }
 }
 
 void expireCommand(redisClient *c) {
         return;
     }
 }
 
 void expireCommand(redisClient *c) {

-    expireGenericCommand(c,c->argv[1],c->argv[2],0);
+    expireGenericCommand(c,mstime(),UNIT_SECONDS);

 }
 
 void expireatCommand(redisClient *c) {
 }
 
 void expireatCommand(redisClient *c) {

-    expireGenericCommand(c,c->argv[1],c->argv[2],time(NULL));
+    expireGenericCommand(c,0,UNIT_SECONDS);

 }
 
 }
 

-void ttlCommand(redisClient *c) {
-    time_t expire;
-    int ttl = -1;
+void pexpireCommand(redisClient *c) {
+    expireGenericCommand(c,mstime(),UNIT_MILLISECONDS);
+}
+
+void pexpireatCommand(redisClient *c) {
+    expireGenericCommand(c,0,UNIT_MILLISECONDS);
+}
+
+void ttlGenericCommand(redisClient *c, int output_ms) {
+    long long expire, ttl = -1;

 
     expire = getExpire(c->db,c->argv[1]);
     if (expire != -1) {
 
     expire = getExpire(c->db,c->argv[1]);
     if (expire != -1) {

-        ttl = (int) (expire-time(NULL));
+        ttl = expire-mstime();

         if (ttl < 0) ttl = -1;
     }
         if (ttl < 0) ttl = -1;
     }

-    addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",ttl));
+    if (ttl == -1) {
+        addReplyLongLong(c,-1);
+    } else {
+        addReplyLongLong(c,output_ms ? ttl : ((ttl+500)/1000));
+    }
+}
+
+void ttlCommand(redisClient *c) {
+    ttlGenericCommand(c, 0);
+}
+
+void pttlCommand(redisClient *c) {
+    ttlGenericCommand(c, 1);
+}
+
+void persistCommand(redisClient *c) {
+    dictEntry *de;
+
+    de = dictFind(c->db->dict,c->argv[1]->ptr);
+    if (de == NULL) {
+        addReply(c,shared.czero);
+    } else {
+        if (removeExpire(c->db,c->argv[1])) {
+            addReply(c,shared.cone);
+            server.dirty++;
+        } else {
+            addReply(c,shared.czero);
+        }
+    }

 }
 
 }
 

+/* -----------------------------------------------------------------------------
+ * API to get key arguments from commands
+ * ---------------------------------------------------------------------------*/
+
+int *getKeysUsingCommandTable(struct redisCommand *cmd,robj **argv, int argc, int *numkeys) {
+    int j, i = 0, last, *keys;
+    REDIS_NOTUSED(argv);

 
 

+    if (cmd->firstkey == 0) {
+        *numkeys = 0;
+        return NULL;
+    }
+    last = cmd->lastkey;
+    if (last < 0) last = argc+last;
+    keys = zmalloc(sizeof(int)*((last - cmd->firstkey)+1));
+    for (j = cmd->firstkey; j <= last; j += cmd->keystep) {
+        redisAssert(j < argc);
+        keys[i++] = j;
+    }
+    *numkeys = i;
+    return keys;
+}
+
+int *getKeysFromCommand(struct redisCommand *cmd,robj **argv, int argc, int *numkeys, int flags) {
+    if (cmd->getkeys_proc) {
+        return cmd->getkeys_proc(cmd,argv,argc,numkeys,flags);
+    } else {
+        return getKeysUsingCommandTable(cmd,argv,argc,numkeys);
+    }
+}
+
+void getKeysFreeResult(int *result) {
+    zfree(result);
+}
+
+int *noPreloadGetKeys(struct redisCommand *cmd,robj **argv, int argc, int *numkeys, int flags) {
+    if (flags & REDIS_GETKEYS_PRELOAD) {
+        *numkeys = 0;
+        return NULL;
+    } else {
+        return getKeysUsingCommandTable(cmd,argv,argc,numkeys);
+    }
+}
+
+int *renameGetKeys(struct redisCommand *cmd,robj **argv, int argc, int *numkeys, int flags) {
+    if (flags & REDIS_GETKEYS_PRELOAD) {
+        int *keys = zmalloc(sizeof(int));
+        *numkeys = 1;
+        keys[0] = 1;
+        return keys;
+    } else {
+        return getKeysUsingCommandTable(cmd,argv,argc,numkeys);
+    }
+}
+
+int *zunionInterGetKeys(struct redisCommand *cmd,robj **argv, int argc, int *numkeys, int flags) {
+    int i, num, *keys;
+    REDIS_NOTUSED(cmd);
+    REDIS_NOTUSED(flags);
+
+    num = atoi(argv[2]->ptr);
+    /* Sanity check. Don't return any key if the command is going to
+     * reply with syntax error. */
+    if (num > (argc-3)) {
+        *numkeys = 0;
+        return NULL;
+    }
+    keys = zmalloc(sizeof(int)*num);
+    for (i = 0; i < num; i++) keys[i] = 3+i;
+    *numkeys = num;
+    return keys;
+}