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     touchWatchedKey(db,key);
  50     return lookupKey(db,key);
  51 }
  52
  53 robj *lookupKeyReadOrReply(redisClient *c, robj *key, robj *reply) {
  54     robj *o = lookupKeyRead(c->db, key);
  55     if (!o) addReply(c,reply);
  56     return o;
  57 }
  58
  59 robj *lookupKeyWriteOrReply(redisClient *c, robj *key, robj *reply) {
  60     robj *o = lookupKeyWrite(c->db, key);
  61     if (!o) addReply(c,reply);
  62     return o;
  63 }
  64
  65 /* Add the key to the DB. If the key already exists REDIS_ERR is returned,
  66  * otherwise REDIS_OK is returned, and the caller should increment the
  67  * refcount of 'val'. */
  68 int dbAdd(redisDb *db, robj *key, robj *val) {
  69     /* Perform a lookup before adding the key, as we need to copy the
  70      * key value. */
  71     if (dictFind(db->dict, key->ptr) != NULL) {
  72         return REDIS_ERR;
  73     } else {
  74         sds copy = sdsdup(key->ptr);
  75         dictAdd(db->dict, copy, val);
  76         return REDIS_OK;
  77     }
  78 }
  79
  80 /* If the key does not exist, this is just like dbAdd(). Otherwise
  81  * the value associated to the key is replaced with the new one.
  82  *
  83  * On update (key already existed) 0 is returned. Otherwise 1. */
  84 int dbReplace(redisDb *db, robj *key, robj *val) {
  85     if (dictFind(db->dict,key->ptr) == NULL) {
  86         sds copy = sdsdup(key->ptr);
  87         dictAdd(db->dict, copy, val);
  88         return 1;
  89     } else {
  90         dictReplace(db->dict, key->ptr, val);
  91         return 0;
  92     }
  93 }
  94
  95 int dbExists(redisDb *db, robj *key) {
  96     return dictFind(db->dict,key->ptr) != NULL;
  97 }
  98
  99 /* Return a random key, in form of a Redis object.
 100  * If there are no keys, NULL is returned.
 101  *
 102  * The function makes sure to return keys not already expired. */
 103 robj *dbRandomKey(redisDb *db) {
 104     struct dictEntry *de;
 105
 106     while(1) {
 107         sds key;
 108         robj *keyobj;
 109
 110         de = dictGetRandomKey(db->dict);
 111         if (de == NULL) return NULL;
 112
 113         key = dictGetEntryKey(de);
 114         keyobj = createStringObject(key,sdslen(key));
 115         if (dictFind(db->expires,key)) {
 116             if (expireIfNeeded(db,keyobj)) {
 117                 decrRefCount(keyobj);
 118                 continue; /* search for another key. This expired. */
 119             }
 120         }
 121         return keyobj;
 122     }
 123 }
 124
 125 /* Delete a key, value, and associated expiration entry if any, from the DB */
 126 int dbDelete(redisDb *db, robj *key) {
 127     /* Deleting an entry from the expires dict will not free the sds of
 128      * the key, because it is shared with the main dictionary. */
 129     if (dictSize(db->expires) > 0) dictDelete(db->expires,key->ptr);
 130     return dictDelete(db->dict,key->ptr) == DICT_OK;
 131 }
 132
 133 /* Empty the whole database */
 134 long long emptyDb() {
 135     int j;
 136     long long removed = 0;
 137
 138     for (j = 0; j < server.dbnum; j++) {
 139         removed += dictSize(server.db[j].dict);
 140         dictEmpty(server.db[j].dict);
 141         dictEmpty(server.db[j].expires);
 142     }
 143     return removed;
 144 }
 145
 146 int selectDb(redisClient *c, int id) {
 147     if (id < 0 || id >= server.dbnum)
 148         return REDIS_ERR;
 149     c->db = &server.db[id];
 150     return REDIS_OK;
 151 }
 152
 153 /*-----------------------------------------------------------------------------
 154  * Type agnostic commands operating on the key space
 155  *----------------------------------------------------------------------------*/
 156
 157 void flushdbCommand(redisClient *c) {
 158     server.dirty += dictSize(c->db->dict);
 159     touchWatchedKeysOnFlush(c->db->id);
 160     dictEmpty(c->db->dict);
 161     dictEmpty(c->db->expires);
 162     addReply(c,shared.ok);
 163 }
 164
 165 void flushallCommand(redisClient *c) {
 166     touchWatchedKeysOnFlush(-1);
 167     server.dirty += emptyDb();
 168     addReply(c,shared.ok);
 169     if (server.bgsavechildpid != -1) {
 170         kill(server.bgsavechildpid,SIGKILL);
 171         rdbRemoveTempFile(server.bgsavechildpid);
 172     }
 173     rdbSave(server.dbfilename);
 174     server.dirty++;
 175 }
 176
 177 void delCommand(redisClient *c) {
 178     int deleted = 0, j;
 179
 180     for (j = 1; j < c->argc; j++) {
 181         if (dbDelete(c->db,c->argv[j])) {
 182             touchWatchedKey(c->db,c->argv[j]);
 183             server.dirty++;
 184             deleted++;
 185         }
 186     }
 187     addReplyLongLong(c,deleted);
 188 }
 189
 190 void existsCommand(redisClient *c) {
 191     expireIfNeeded(c->db,c->argv[1]);
 192     if (dbExists(c->db,c->argv[1])) {
 193         addReply(c, shared.cone);
 194     } else {
 195         addReply(c, shared.czero);
 196     }
 197 }
 198
 199 void selectCommand(redisClient *c) {
 200     int id = atoi(c->argv[1]->ptr);
 201
 202     if (selectDb(c,id) == REDIS_ERR) {
 203         addReplySds(c,sdsnew("-ERR invalid DB index\r\n"));
 204     } else {
 205         addReply(c,shared.ok);
 206     }
 207 }
 208
 209 void randomkeyCommand(redisClient *c) {
 210     robj *key;
 211
 212     if ((key = dbRandomKey(c->db)) == NULL) {
 213         addReply(c,shared.nullbulk);
 214         return;
 215     }
 216
 217     addReplyBulk(c,key);
 218     decrRefCount(key);
 219 }
 220
 221 void keysCommand(redisClient *c) {
 222     dictIterator *di;
 223     dictEntry *de;
 224     sds pattern = c->argv[1]->ptr;
 225     int plen = sdslen(pattern);
 226     unsigned long numkeys = 0;
 227     robj *lenobj = createObject(REDIS_STRING,NULL);
 228
 229     di = dictGetIterator(c->db->dict);
 230     addReply(c,lenobj);
 231     decrRefCount(lenobj);
 232     while((de = dictNext(di)) != NULL) {
 233         sds key = dictGetEntryKey(de);
 234         robj *keyobj;
 235
 236         if ((pattern[0] == '*' && pattern[1] == '\0') ||
 237             stringmatchlen(pattern,plen,key,sdslen(key),0)) {
 238             keyobj = createStringObject(key,sdslen(key));
 239             if (expireIfNeeded(c->db,keyobj) == 0) {
 240                 addReplyBulk(c,keyobj);
 241                 numkeys++;
 242             }
 243             decrRefCount(keyobj);
 244         }
 245     }
 246     dictReleaseIterator(di);
 247     lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n",numkeys);
 248 }
 249
 250 void dbsizeCommand(redisClient *c) {
 251     addReplySds(c,
 252         sdscatprintf(sdsempty(),":%lu\r\n",dictSize(c->db->dict)));
 253 }
 254
 255 void lastsaveCommand(redisClient *c) {
 256     addReplySds(c,
 257         sdscatprintf(sdsempty(),":%lu\r\n",server.lastsave));
 258 }
 259
 260 void typeCommand(redisClient *c) {
 261     robj *o;
 262     char *type;
 263
 264     o = lookupKeyRead(c->db,c->argv[1]);
 265     if (o == NULL) {
 266         type = "+none";
 267     } else {
 268         switch(o->type) {
 269         case REDIS_STRING: type = "+string"; break;
 270         case REDIS_LIST: type = "+list"; break;
 271         case REDIS_SET: type = "+set"; break;
 272         case REDIS_ZSET: type = "+zset"; break;
 273         case REDIS_HASH: type = "+hash"; break;
 274         default: type = "+unknown"; break;
 275         }
 276     }
 277     addReplySds(c,sdsnew(type));
 278     addReply(c,shared.crlf);
 279 }
 280
 281 void saveCommand(redisClient *c) {
 282     if (server.bgsavechildpid != -1) {
 283         addReplySds(c,sdsnew("-ERR background save in progress\r\n"));
 284         return;
 285     }
 286     if (rdbSave(server.dbfilename) == REDIS_OK) {
 287         addReply(c,shared.ok);
 288     } else {
 289         addReply(c,shared.err);
 290     }
 291 }
 292
 293 void bgsaveCommand(redisClient *c) {
 294     if (server.bgsavechildpid != -1) {
 295         addReplySds(c,sdsnew("-ERR background save already in progress\r\n"));
 296         return;
 297     }
 298     if (rdbSaveBackground(server.dbfilename) == REDIS_OK) {
 299         char *status = "+Background saving started\r\n";
 300         addReplySds(c,sdsnew(status));
 301     } else {
 302         addReply(c,shared.err);
 303     }
 304 }
 305
 306 void shutdownCommand(redisClient *c) {
 307     if (prepareForShutdown() == REDIS_OK)
 308         exit(0);
 309     addReplySds(c, sdsnew("-ERR Errors trying to SHUTDOWN. Check logs.\r\n"));
 310 }
 311
 312 void renameGenericCommand(redisClient *c, int nx) {
 313     robj *o;
 314
 315     /* To use the same key as src and dst is probably an error */
 316     if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
 317         addReply(c,shared.sameobjecterr);
 318         return;
 319     }
 320
 321     if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
 322         return;
 323
 324     incrRefCount(o);
 325     deleteIfVolatile(c->db,c->argv[2]);
 326     if (dbAdd(c->db,c->argv[2],o) == REDIS_ERR) {
 327         if (nx) {
 328             decrRefCount(o);
 329             addReply(c,shared.czero);
 330             return;
 331         }
 332         dbReplace(c->db,c->argv[2],o);
 333     }
 334     dbDelete(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         return;
 476     } else {
 477         time_t when = time(NULL)+seconds;
 478         if (setExpire(c->db,key,when)) {
 479             addReply(c,shared.cone);
 480             server.dirty++;
 481         } else {
 482             addReply(c,shared.czero);
 483         }
 484         return;
 485     }
 486 }
 487
 488 void expireCommand(redisClient *c) {
 489     expireGenericCommand(c,c->argv[1],c->argv[2],0);
 490 }
 491
 492 void expireatCommand(redisClient *c) {
 493     expireGenericCommand(c,c->argv[1],c->argv[2],time(NULL));
 494 }
 495
 496 void ttlCommand(redisClient *c) {
 497     time_t expire;
 498     int ttl = -1;
 499
 500     expire = getExpire(c->db,c->argv[1]);
 501     if (expire != -1) {
 502         ttl = (int) (expire-time(NULL));
 503         if (ttl < 0) ttl = -1;
 504     }
 505     addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",ttl));
 506 }
 507
 508