src/db.c

   1 #include "redis.h"
   2
   3 #include <signal.h>
   4
   5 /*-----------------------------------------------------------------------------
   6  * C-level DB API
   7  *----------------------------------------------------------------------------*/
   8
   9 robj *lookupKey(redisDb *db, robj *key) {
  10     dictEntry *de = dictFind(db->dict,key->ptr);
  11     if (de) {
  12         robj *val = dictGetEntryVal(de);
  13
  14         if (server.vm_enabled) {
  15             if (val->storage == REDIS_VM_MEMORY ||
  16                 val->storage == REDIS_VM_SWAPPING)
  17             {
  18                 /* If we were swapping the object out, cancel the operation */
  19                 if (val->storage == REDIS_VM_SWAPPING)
  20                     vmCancelThreadedIOJob(val);
  21                 /* Update the access time for the aging algorithm. */
  22                 val->lru = server.lruclock;
  23             } else {
  24                 int notify = (val->storage == REDIS_VM_LOADING);
  25
  26                 /* Our value was swapped on disk. Bring it at home. */
  27                 redisAssert(val->type == REDIS_VMPOINTER);
  28                 val = vmLoadObject(val);
  29                 dictGetEntryVal(de) = val;
  30
  31                 /* Clients blocked by the VM subsystem may be waiting for
  32                  * this key... */
  33                 if (notify) handleClientsBlockedOnSwappedKey(db,key);
  34             }
  35         }
  36         return val;
  37     } else {
  38         return NULL;
  39     }
  40 }
  41
  42 robj *lookupKeyRead(redisDb *db, robj *key) {
  43     expireIfNeeded(db,key);
  44     return lookupKey(db,key);
  45 }
  46
  47 robj *lookupKeyWrite(redisDb *db, robj *key) {
  48     deleteIfVolatile(db,key);
  49     return lookupKey(db,key);
  50 }
  51
  52 robj *lookupKeyReadOrReply(redisClient *c, robj *key, robj *reply) {
  53     robj *o = lookupKeyRead(c->db, key);
  54     if (!o) addReply(c,reply);
  55     return o;
  56 }
  57
  58 robj *lookupKeyWriteOrReply(redisClient *c, robj *key, robj *reply) {
  59     robj *o = lookupKeyWrite(c->db, key);
  60     if (!o) addReply(c,reply);
  61     return o;
  62 }
  63
  64 /* Add the key to the DB. If the key already exists REDIS_ERR is returned,
  65  * otherwise REDIS_OK is returned, and the caller should increment the
  66  * refcount of 'val'. */
  67 int dbAdd(redisDb *db, robj *key, robj *val) {
  68     /* Perform a lookup before adding the key, as we need to copy the
  69      * key value. */
  70     if (dictFind(db->dict, key->ptr) != NULL) {
  71         return REDIS_ERR;
  72     } else {
  73         sds copy = sdsdup(key->ptr);
  74         dictAdd(db->dict, copy, val);
  75         return REDIS_OK;
  76     }
  77 }
  78
  79 /* If the key does not exist, this is just like dbAdd(). Otherwise
  80  * the value associated to the key is replaced with the new one.
  81  *
  82  * On update (key already existed) 0 is returned. Otherwise 1. */
  83 int dbReplace(redisDb *db, robj *key, robj *val) {
  84     if (dictFind(db->dict,key->ptr) == NULL) {
  85         sds copy = sdsdup(key->ptr);
  86         dictAdd(db->dict, copy, val);
  87         return 1;
  88     } else {
  89         dictReplace(db->dict, key->ptr, val);
  90         return 0;
  91     }
  92 }
  93
  94 int dbExists(redisDb *db, robj *key) {
  95     return dictFind(db->dict,key->ptr) != NULL;
  96 }
  97
  98 /* Return a random key, in form of a Redis object.
  99  * If there are no keys, NULL is returned.
 100  *
 101  * The function makes sure to return keys not already expired. */
 102 robj *dbRandomKey(redisDb *db) {
 103     struct dictEntry *de;
 104
 105     while(1) {
 106         sds key;
 107         robj *keyobj;
 108
 109         de = dictGetRandomKey(db->dict);
 110         if (de == NULL) return NULL;
 111
 112         key = dictGetEntryKey(de);
 113         keyobj = createStringObject(key,sdslen(key));
 114         if (dictFind(db->expires,key)) {
 115             if (expireIfNeeded(db,keyobj)) {
 116                 decrRefCount(keyobj);
 117                 continue; /* search for another key. This expired. */
 118             }
 119         }
 120         return keyobj;
 121     }
 122 }
 123
 124 /* Delete a key, value, and associated expiration entry if any, from the DB */
 125 int dbDelete(redisDb *db, robj *key) {
 126     /* Deleting an entry from the expires dict will not free the sds of
 127      * the key, because it is shared with the main dictionary. */
 128     if (dictSize(db->expires) > 0) dictDelete(db->expires,key->ptr);
 129     return dictDelete(db->dict,key->ptr) == DICT_OK;
 130 }
 131
 132 /* Empty the whole database */
 133 long long emptyDb() {
 134     int j;
 135     long long removed = 0;
 136
 137     for (j = 0; j < server.dbnum; j++) {
 138         removed += dictSize(server.db[j].dict);
 139         dictEmpty(server.db[j].dict);
 140         dictEmpty(server.db[j].expires);
 141     }
 142     return removed;
 143 }
 144
 145 int selectDb(redisClient *c, int id) {
 146     if (id < 0 || id >= server.dbnum)
 147         return REDIS_ERR;
 148     c->db = &server.db[id];
 149     return REDIS_OK;
 150 }
 151
 152 /*-----------------------------------------------------------------------------
 153  * Type agnostic commands operating on the key space
 154  *----------------------------------------------------------------------------*/
 155
 156 void flushdbCommand(redisClient *c) {
 157     server.dirty += dictSize(c->db->dict);
 158     touchWatchedKeysOnFlush(c->db->id);
 159     dictEmpty(c->db->dict);
 160     dictEmpty(c->db->expires);
 161     addReply(c,shared.ok);
 162 }
 163
 164 void flushallCommand(redisClient *c) {
 165     touchWatchedKeysOnFlush(-1);
 166     server.dirty += emptyDb();
 167     addReply(c,shared.ok);
 168     if (server.bgsavechildpid != -1) {
 169         kill(server.bgsavechildpid,SIGKILL);
 170         rdbRemoveTempFile(server.bgsavechildpid);
 171     }
 172     rdbSave(server.dbfilename);
 173     server.dirty++;
 174 }
 175
 176 void delCommand(redisClient *c) {
 177     int deleted = 0, j;
 178
 179     for (j = 1; j < c->argc; j++) {
 180         if (dbDelete(c->db,c->argv[j])) {
 181             touchWatchedKey(c->db,c->argv[j]);
 182             server.dirty++;
 183             deleted++;
 184         }
 185     }
 186     addReplyLongLong(c,deleted);
 187 }
 188
 189 void existsCommand(redisClient *c) {
 190     expireIfNeeded(c->db,c->argv[1]);
 191     if (dbExists(c->db,c->argv[1])) {
 192         addReply(c, shared.cone);
 193     } else {
 194         addReply(c, shared.czero);
 195     }
 196 }
 197
 198 void selectCommand(redisClient *c) {
 199     int id = atoi(c->argv[1]->ptr);
 200
 201     if (selectDb(c,id) == REDIS_ERR) {
 202         addReplySds(c,sdsnew("-ERR invalid DB index\r\n"));
 203     } else {
 204         addReply(c,shared.ok);
 205     }
 206 }
 207
 208 void randomkeyCommand(redisClient *c) {
 209     robj *key;
 210
 211     if ((key = dbRandomKey(c->db)) == NULL) {
 212         addReply(c,shared.nullbulk);
 213         return;
 214     }
 215
 216     addReplyBulk(c,key);
 217     decrRefCount(key);
 218 }
 219
 220 void keysCommand(redisClient *c) {
 221     dictIterator *di;
 222     dictEntry *de;
 223     sds pattern = c->argv[1]->ptr;
 224     int plen = sdslen(pattern);
 225     unsigned long numkeys = 0;
 226     robj *lenobj = createObject(REDIS_STRING,NULL);
 227
 228     di = dictGetIterator(c->db->dict);
 229     addReply(c,lenobj);
 230     decrRefCount(lenobj);
 231     while((de = dictNext(di)) != NULL) {
 232         sds key = dictGetEntryKey(de);
 233         robj *keyobj;
 234
 235         if ((pattern[0] == '*' && pattern[1] == '\0') ||
 236             stringmatchlen(pattern,plen,key,sdslen(key),0)) {
 237             keyobj = createStringObject(key,sdslen(key));
 238             if (expireIfNeeded(c->db,keyobj) == 0) {
 239                 addReplyBulk(c,keyobj);
 240                 numkeys++;
 241             }
 242             decrRefCount(keyobj);
 243         }
 244     }
 245     dictReleaseIterator(di);
 246     lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n",numkeys);
 247 }
 248
 249 void dbsizeCommand(redisClient *c) {
 250     addReplySds(c,
 251         sdscatprintf(sdsempty(),":%lu\r\n",dictSize(c->db->dict)));
 252 }
 253
 254 void lastsaveCommand(redisClient *c) {
 255     addReplySds(c,
 256         sdscatprintf(sdsempty(),":%lu\r\n",server.lastsave));
 257 }
 258
 259 void typeCommand(redisClient *c) {
 260     robj *o;
 261     char *type;
 262
 263     o = lookupKeyRead(c->db,c->argv[1]);
 264     if (o == NULL) {
 265         type = "+none";
 266     } else {
 267         switch(o->type) {
 268         case REDIS_STRING: type = "+string"; break;
 269         case REDIS_LIST: type = "+list"; break;
 270         case REDIS_SET: type = "+set"; break;
 271         case REDIS_ZSET: type = "+zset"; break;
 272         case REDIS_HASH: type = "+hash"; break;
 273         default: type = "+unknown"; break;
 274         }
 275     }
 276     addReplySds(c,sdsnew(type));
 277     addReply(c,shared.crlf);
 278 }
 279
 280 void saveCommand(redisClient *c) {
 281     if (server.bgsavechildpid != -1) {
 282         addReplySds(c,sdsnew("-ERR background save in progress\r\n"));
 283         return;
 284     }
 285     if (rdbSave(server.dbfilename) == REDIS_OK) {
 286         addReply(c,shared.ok);
 287     } else {
 288         addReply(c,shared.err);
 289     }
 290 }
 291
 292 void bgsaveCommand(redisClient *c) {
 293     if (server.bgsavechildpid != -1) {
 294         addReplySds(c,sdsnew("-ERR background save already in progress\r\n"));
 295         return;
 296     }
 297     if (rdbSaveBackground(server.dbfilename) == REDIS_OK) {
 298         char *status = "+Background saving started\r\n";
 299         addReplySds(c,sdsnew(status));
 300     } else {
 301         addReply(c,shared.err);
 302     }
 303 }
 304
 305 void shutdownCommand(redisClient *c) {
 306     if (prepareForShutdown() == REDIS_OK)
 307         exit(0);
 308     addReplySds(c, sdsnew("-ERR Errors trying to SHUTDOWN. Check logs.\r\n"));
 309 }
 310
 311 void renameGenericCommand(redisClient *c, int nx) {
 312     robj *o;
 313
 314     /* To use the same key as src and dst is probably an error */
 315     if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
 316         addReply(c,shared.sameobjecterr);
 317         return;
 318     }
 319
 320     if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
 321         return;
 322
 323     incrRefCount(o);
 324     deleteIfVolatile(c->db,c->argv[2]);
 325     if (dbAdd(c->db,c->argv[2],o) == REDIS_ERR) {
 326         if (nx) {
 327             decrRefCount(o);
 328             addReply(c,shared.czero);
 329             return;
 330         }
 331         dbReplace(c->db,c->argv[2],o);
 332     }
 333     dbDelete(c->db,c->argv[1]);
 334     touchWatchedKey(c->db,c->argv[1]);
 335     touchWatchedKey(c->db,c->argv[2]);
 336     server.dirty++;
 337     addReply(c,nx ? shared.cone : shared.ok);
 338 }
 339
 340 void renameCommand(redisClient *c) {
 341     renameGenericCommand(c,0);
 342 }
 343
 344 void renamenxCommand(redisClient *c) {
 345     renameGenericCommand(c,1);
 346 }
 347
 348 void moveCommand(redisClient *c) {
 349     robj *o;
 350     redisDb *src, *dst;
 351     int srcid;
 352
 353     /* Obtain source and target DB pointers */
 354     src = c->db;
 355     srcid = c->db->id;
 356     if (selectDb(c,atoi(c->argv[2]->ptr)) == REDIS_ERR) {
 357         addReply(c,shared.outofrangeerr);
 358         return;
 359     }
 360     dst = c->db;
 361     selectDb(c,srcid); /* Back to the source DB */
 362
 363     /* If the user is moving using as target the same
 364      * DB as the source DB it is probably an error. */
 365     if (src == dst) {
 366         addReply(c,shared.sameobjecterr);
 367         return;
 368     }
 369
 370     /* Check if the element exists and get a reference */
 371     o = lookupKeyWrite(c->db,c->argv[1]);
 372     if (!o) {
 373         addReply(c,shared.czero);
 374         return;
 375     }
 376
 377     /* Try to add the element to the target DB */
 378     deleteIfVolatile(dst,c->argv[1]);
 379     if (dbAdd(dst,c->argv[1],o) == REDIS_ERR) {
 380         addReply(c,shared.czero);
 381         return;
 382     }
 383     incrRefCount(o);
 384
 385     /* OK! key moved, free the entry in the source DB */
 386     dbDelete(src,c->argv[1]);
 387     server.dirty++;
 388     addReply(c,shared.cone);
 389 }
 390
 391 /*-----------------------------------------------------------------------------
 392  * Expires API
 393  *----------------------------------------------------------------------------*/
 394
 395 int removeExpire(redisDb *db, robj *key) {
 396     /* An expire may only be removed if there is a corresponding entry in the
 397      * main dict. Otherwise, the key will never be freed. */
 398     redisAssert(dictFind(db->dict,key->ptr) != NULL);
 399     if (dictDelete(db->expires,key->ptr) == DICT_OK) {
 400         return 1;
 401     } else {
 402         return 0;
 403     }
 404 }
 405
 406 int setExpire(redisDb *db, robj *key, time_t when) {
 407     dictEntry *de;
 408
 409     /* Reuse the sds from the main dict in the expire dict */
 410     redisAssert((de = dictFind(db->dict,key->ptr)) != NULL);
 411     if (dictAdd(db->expires,dictGetEntryKey(de),(void*)when) == DICT_ERR) {
 412         return 0;
 413     } else {
 414         return 1;
 415     }
 416 }
 417
 418 /* Return the expire time of the specified key, or -1 if no expire
 419  * is associated with this key (i.e. the key is non volatile) */
 420 time_t getExpire(redisDb *db, robj *key) {
 421     dictEntry *de;
 422
 423     /* No expire? return ASAP */
 424     if (dictSize(db->expires) == 0 ||
 425        (de = dictFind(db->expires,key->ptr)) == NULL) return -1;
 426
 427     /* The entry was found in the expire dict, this means it should also
 428      * be present in the main dict (safety check). */
 429     redisAssert(dictFind(db->dict,key->ptr) != NULL);
 430     return (time_t) dictGetEntryVal(de);
 431 }
 432
 433 int expireIfNeeded(redisDb *db, robj *key) {
 434     time_t when = getExpire(db,key);
 435     if (when < 0) return 0;
 436
 437     /* Return when this key has not expired */
 438     if (time(NULL) <= when) return 0;
 439
 440     /* Delete the key */
 441     server.stat_expiredkeys++;
 442     server.dirty++;
 443     return dbDelete(db,key);
 444 }
 445
 446 int deleteIfVolatile(redisDb *db, robj *key) {
 447     if (getExpire(db,key) < 0) return 0;
 448
 449     /* Delete the key */
 450     server.stat_expiredkeys++;
 451     server.dirty++;
 452     return dbDelete(db,key);
 453 }
 454
 455 /*-----------------------------------------------------------------------------
 456  * Expires Commands
 457  *----------------------------------------------------------------------------*/
 458
 459 void expireGenericCommand(redisClient *c, robj *key, robj *param, long offset) {
 460     dictEntry *de;
 461     time_t seconds;
 462
 463     if (getLongFromObjectOrReply(c, param, &seconds, NULL) != REDIS_OK) return;
 464
 465     seconds -= offset;
 466
 467     de = dictFind(c->db->dict,key->ptr);
 468     if (de == NULL) {
 469         addReply(c,shared.czero);
 470         return;
 471     }
 472     if (seconds <= 0) {
 473         if (dbDelete(c->db,key)) server.dirty++;
 474         addReply(c, shared.cone);
 475         touchWatchedKey(c->db,key);
 476         return;
 477     } else {
 478         time_t when = time(NULL)+seconds;
 479         if (setExpire(c->db,key,when)) {
 480             addReply(c,shared.cone);
 481             touchWatchedKey(c->db,key);
 482             server.dirty++;
 483         } else {
 484             addReply(c,shared.czero);
 485         }
 486         return;
 487     }
 488 }
 489
 490 void expireCommand(redisClient *c) {
 491     expireGenericCommand(c,c->argv[1],c->argv[2],0);
 492 }
 493
 494 void expireatCommand(redisClient *c) {
 495     expireGenericCommand(c,c->argv[1],c->argv[2],time(NULL));
 496 }
 497
 498 void ttlCommand(redisClient *c) {
 499     time_t expire;
 500     int ttl = -1;
 501
 502     expire = getExpire(c->db,c->argv[1]);
 503     if (expire != -1) {
 504         ttl = (int) (expire-time(NULL));
 505         if (ttl < 0) ttl = -1;
 506     }
 507     addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",ttl));
 508 }