* 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) {
robj *val = dictGetEntryVal(de);
- /* Update the access time for the aging algorithm. */
- val->lru = server.lruclock;
-
- 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);
- } 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);
- }
+ /* 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.bgsavechildpid == -1 && server.bgrewritechildpid == -1)
+ val->lru = server.lruclock;
+
+ if (server.ds_enabled &&
+ 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;
} else {
+ time_t expire;
+ robj *val;
+
+ /* 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. */
+ if (server.ds_enabled && cacheKeyMayExist(db,key)) {
+ 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);
+ redisAssert(retval == REDIS_OK);
+ if (expire != -1) setExpire(db,key,expire);
+ server.stat_keyspace_hits++;
+ return val;
+ } else {
+ cacheSetKeyDoesNotExist(db,key);
+ }
+ }
server.stat_keyspace_misses++;
return NULL;
}
} else {
sds copy = sdsdup(key->ptr);
dictAdd(db->dict, copy, val);
+ if (server.ds_enabled) cacheSetKeyMayExist(db,key);
return REDIS_OK;
}
}
*
* 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) {
+ 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) {
/* Delete a key, value, and associated expiration entry if any, from the DB */
int dbDelete(redisDb *db, robj *key) {
- /* If VM is enabled make sure to awake waiting clients for this key:
- * deleting the key will kill the I/O thread bringing the key from swap
- * to memory, so the client will never be notified and unblocked if we
- * don't do it now. */
- if (server.vm_enabled) handleClientsBlockedOnSwappedKey(db,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);
+ 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. */
if (dictSize(db->expires) > 0) dictDelete(db->expires,key->ptr);
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;
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;
}
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);
+ if (server.ds_enabled)
+ cacheScheduleIO(db,key,REDIS_IO_SAVE);
+}
+
+void signalFlushedDb(int dbid) {
+ touchWatchedKeysOnFlush(dbid);
+}
+
/*-----------------------------------------------------------------------------
* 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);
+ if (server.ds_enabled) dsFlushDb(c->db->id);
addReply(c,shared.ok);
}
void flushallCommand(redisClient *c) {
- touchWatchedKeysOnFlush(-1);
+ signalFlushedDb(-1);
server.dirty += emptyDb();
addReply(c,shared.ok);
if (server.bgsavechildpid != -1) {
kill(server.bgsavechildpid,SIGKILL);
rdbRemoveTempFile(server.bgsavechildpid);
}
- rdbSave(server.dbfilename);
+ if (server.ds_enabled)
+ dsFlushDb(-1);
+ else
+ rdbSave(server.dbfilename);
server.dirty++;
}
int deleted = 0, j;
for (j = 1; j < c->argc; j++) {
+ if (server.ds_enabled) {
+ lookupKeyRead(c->db,c->argv[j]);
+ /* FIXME: this can be optimized a lot, no real need to load
+ * a possibly huge value. */
+ }
if (dbDelete(c->db,c->argv[j])) {
- touchWatchedKey(c->db,c->argv[j]);
+ signalModifiedKey(c->db,c->argv[j]);
server.dirty++;
deleted++;
+ } else if (server.ds_enabled) {
+ if (cacheKeyMayExist(c->db,c->argv[j]) &&
+ dsExists(c->db,c->argv[j]))
+ {
+ cacheScheduleIO(c->db,c->argv[j],REDIS_IO_SAVE);
+ deleted = 1;
+ }
}
}
addReplyLongLong(c,deleted);
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);
dbReplace(c->db,c->argv[2],o);
}
dbDelete(c->db,c->argv[1]);
- touchWatchedKey(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);
}
* will be consistent even if we allow write operations against expiring
* keys. */
void propagateExpire(redisDb *db, robj *key) {
- struct redisCommand *cmd;
robj *argv[2];
- cmd = lookupCommand("del");
argv[0] = createStringObject("DEL",3);
argv[1] = key;
incrRefCount(key);
if (server.appendonly)
- feedAppendOnlyFile(cmd,db->id,argv,2);
+ feedAppendOnlyFile(server.delCommand,db->id,argv,2);
if (listLength(server.slaves))
replicationFeedSlaves(server.slaves,db->id,argv,2);
if (seconds <= 0) {
if (dbDelete(c->db,key)) server.dirty++;
addReply(c, shared.cone);
- touchWatchedKey(c->db,key);
+ signalModifiedKey(c->db,key);
return;
} else {
time_t when = time(NULL)+seconds;
setExpire(c->db,key,when);
addReply(c,shared.cone);
- touchWatchedKey(c->db,key);
+ signalModifiedKey(c->db,key);
server.dirty++;
return;
}
projects / redis.git / blobdiff