X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/3be00d7ed619c12795da54553230aee15c555532..17b24ff30d5c84c489a9793e35b7497519a878b9:/src/db.c diff --git a/src/db.c b/src/db.c index c985794d..85a22062 100644 --- a/src/db.c +++ b/src/db.c @@ -6,6 +6,35 @@ * C-level DB API *----------------------------------------------------------------------------*/ +/* Important notes on lookup and disk store. + * + * When disk store is enabled on lookup we can have different cases. + * + * a) The key is in memory: + * - If the key is not in IO_SAVEINPROG state we can access it. + * As if it's just IO_SAVE this means we have the key in the IO queue + * but can't be accessed by the IO thread (it requires to be + * translated into an IO Job by the cache cron function.) + * - If the key is in IO_SAVEINPROG we can't touch the key and have + * to blocking wait completion of operations. + * b) The key is not in memory: + * - If it's marked as non existing on disk as well (negative cache) + * we don't need to perform the disk access. + * - if the key MAY EXIST, but is not in memory, and it is marked as IO_SAVE + * then the key can only be a deleted one. As IO_SAVE keys are never + * evicted (dirty state), so the only possibility is that key was deleted. + * - if the key MAY EXIST we need to blocking load it. + * We check that the key is not in IO_SAVEINPROG state before accessing + * the disk object. If it is in this state, we wait. + */ + +void lookupWaitBusyKey(redisDb *db, robj *key) { + /* FIXME: wait just for this key, not everything */ + waitEmptyIOJobsQueue(); + processAllPendingIOJobs(); + redisAssert((cacheScheduleIOGetFlags(db,key) & REDIS_IO_SAVEINPROG) == 0); +} + robj *lookupKey(redisDb *db, robj *key) { dictEntry *de = dictFind(db->dict,key->ptr); if (de) { @@ -20,11 +49,9 @@ robj *lookupKey(redisDb *db, robj *key) { if (server.ds_enabled && cacheScheduleIOGetFlags(db,key) & REDIS_IO_SAVEINPROG) { - /* There is a save in progress for this object! - * Wait for it to get out. */ - waitEmptyIOJobsQueue(); - processAllPendingIOJobs(); - redisAssert(!(cacheScheduleIOGetFlags(db,key) & REDIS_IO_SAVEINPROG)); + /* Need to wait for the key to get unbusy */ + redisLog(REDIS_DEBUG,"Lookup found a key in SAVEINPROG state. Waiting. (Key was in the cache)"); + lookupWaitBusyKey(db,key); } server.stat_keyspace_hits++; return val; @@ -34,14 +61,26 @@ robj *lookupKey(redisDb *db, robj *key) { /* Key not found in the in memory hash table, but if disk store is * enabled we may have this key on disk. If so load it in memory - * in a blocking way. - * - * FIXME: race condition here. If there was an already scheduled - * async loading of this key, what may happen is that the old - * key is loaded in memory if this gets deleted in the meantime. */ + * in a blocking way. */ if (server.ds_enabled && cacheKeyMayExist(db,key)) { - redisLog(REDIS_DEBUG,"Force loading key %s via lookup", - key->ptr); + long flags = cacheScheduleIOGetFlags(db,key); + + /* They key is not in cache, but it has a SAVE op in queue? + * The only possibility is that the key was deleted, since + * dirty keys are not evicted. */ + if (flags & REDIS_IO_SAVE) { + server.stat_keyspace_misses++; + return NULL; + } + + /* At this point we need to blocking load the key in memory. + * The first thing we do is waiting here if the key is busy. */ + if (flags & REDIS_IO_SAVEINPROG) { + redisLog(REDIS_DEBUG,"Lookup found a key in SAVEINPROG state. Waiting (while force loading)."); + lookupWaitBusyKey(db,key); + } + + redisLog(REDIS_DEBUG,"Force loading key %s via lookup", key->ptr); val = dsGet(db,key,&expire); if (val) { int retval = dbAdd(db,key,val); @@ -49,6 +88,8 @@ robj *lookupKey(redisDb *db, robj *key) { if (expire != -1) setExpire(db,key,expire); server.stat_keyspace_hits++; return val; + } else { + cacheSetKeyDoesNotExist(db,key); } } server.stat_keyspace_misses++; @@ -89,9 +130,7 @@ int dbAdd(redisDb *db, robj *key, robj *val) { } else { sds copy = sdsdup(key->ptr); dictAdd(db->dict, copy, val); - if (server.ds_enabled) { - /* FIXME: remove entry from negative cache */ - } + if (server.ds_enabled) cacheSetKeyMayExist(db,key); return REDIS_OK; } } @@ -102,15 +141,18 @@ int dbAdd(redisDb *db, robj *key, robj *val) { * On update (key already existed) 0 is returned. Otherwise 1. */ int dbReplace(redisDb *db, robj *key, robj *val) { robj *oldval; + int retval; if ((oldval = dictFetchValue(db->dict,key->ptr)) == NULL) { sds copy = sdsdup(key->ptr); dictAdd(db->dict, copy, val); - return 1; + retval = 1; } else { dictReplace(db->dict, key->ptr, val); - return 0; + retval = 0; } + if (server.ds_enabled) cacheSetKeyMayExist(db,key); + return retval; } int dbExists(redisDb *db, robj *key) { @@ -148,10 +190,10 @@ int dbDelete(redisDb *db, robj *key) { /* If diskstore is enabled make sure to awake waiting clients for this key * as it is not really useful to wait for a key already deleted to be * loaded from disk. */ - if (server.ds_enabled) handleClientsBlockedOnSwappedKey(db,key); - - /* FIXME: we should mark this key as non existing on disk in the negative - * cache. */ + if (server.ds_enabled) { + handleClientsBlockedOnSwappedKey(db,key); + cacheSetKeyDoesNotExist(db,key); + } /* Deleting an entry from the expires dict will not free the sds of * the key, because it is shared with the main dictionary. */ @@ -159,7 +201,8 @@ int dbDelete(redisDb *db, robj *key) { return dictDelete(db->dict,key->ptr) == DICT_OK; } -/* Empty the whole database */ +/* Empty the whole database. + * If diskstore is enabled this function will just flush the in-memory cache. */ long long emptyDb() { int j; long long removed = 0; @@ -168,6 +211,7 @@ long long emptyDb() { removed += dictSize(server.db[j].dict); dictEmpty(server.db[j].dict); dictEmpty(server.db[j].expires); + if (server.ds_enabled) dictEmpty(server.db[j].io_negcache); } return removed; } @@ -196,8 +240,6 @@ void signalModifiedKey(redisDb *db, robj *key) { void signalFlushedDb(int dbid) { touchWatchedKeysOnFlush(dbid); - if (server.ds_enabled) - dsFlushDb(dbid); } /*----------------------------------------------------------------------------- @@ -209,6 +251,7 @@ void flushdbCommand(redisClient *c) { signalFlushedDb(c->db->id); dictEmpty(c->db->dict); dictEmpty(c->db->expires); + if (server.ds_enabled) dsFlushDb(c->db->id); addReply(c,shared.ok); } @@ -220,7 +263,10 @@ void flushallCommand(redisClient *c) { kill(server.bgsavechildpid,SIGKILL); rdbRemoveTempFile(server.bgsavechildpid); } - rdbSave(server.dbfilename); + if (server.ds_enabled) + dsFlushDb(-1); + else + rdbSave(server.dbfilename); server.dirty++; } @@ -261,6 +307,10 @@ void existsCommand(redisClient *c) { void selectCommand(redisClient *c) { int id = atoi(c->argv[1]->ptr); + if (server.cluster_enabled) { + addReplyError(c,"SELECT is not allowed in cluster mode"); + return; + } if (selectDb(c,id) == REDIS_ERR) { addReplyError(c,"invalid DB index"); } else { @@ -335,30 +385,6 @@ void typeCommand(redisClient *c) { addReplyStatus(c,type); } -void saveCommand(redisClient *c) { - if (server.bgsavechildpid != -1) { - addReplyError(c,"Background save already in progress"); - return; - } - if (rdbSave(server.dbfilename) == REDIS_OK) { - addReply(c,shared.ok); - } else { - addReply(c,shared.err); - } -} - -void bgsaveCommand(redisClient *c) { - if (server.bgsavechildpid != -1) { - addReplyError(c,"Background save already in progress"); - return; - } - if (rdbSaveBackground(server.dbfilename) == REDIS_OK) { - addReplyStatus(c,"Background saving started"); - } else { - addReply(c,shared.err); - } -} - void shutdownCommand(redisClient *c) { if (prepareForShutdown() == REDIS_OK) exit(0); @@ -406,6 +432,11 @@ void moveCommand(redisClient *c) { redisDb *src, *dst; int srcid; + if (server.cluster_enabled) { + addReplyError(c,"MOVE is not allowed in cluster mode"); + return; + } + /* Obtain source and target DB pointers */ src = c->db; srcid = c->db->id; @@ -505,6 +536,8 @@ void propagateExpire(redisDb *db, robj *key) { int expireIfNeeded(redisDb *db, robj *key) { time_t when = getExpire(db,key); + if (when < 0) return 0; /* No expire for this key */ + /* 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. @@ -516,8 +549,6 @@ int expireIfNeeded(redisDb *db, robj *key) { return time(NULL) > when; } - if (when < 0) return 0; - /* Return when this key has not expired */ if (time(NULL) <= when) return 0; @@ -570,6 +601,7 @@ void expireatCommand(redisClient *c) { void ttlCommand(redisClient *c) { time_t expire, ttl = -1; + if (server.ds_enabled) lookupKeyRead(c->db,c->argv[1]); expire = getExpire(c->db,c->argv[1]); if (expire != -1) { ttl = (expire-time(NULL)); @@ -593,3 +625,76 @@ void persistCommand(redisClient *c) { } } } + +/* ----------------------------------------------------------------------------- + * 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; +}