+/* SORT command and helper functions.
+ *
+ * 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 "pqsort.h" /* Partial qsort for SORT+LIMIT */
#include <math.h> /* isnan() */
+zskiplistNode* zslGetElementByRank(zskiplist *zsl, unsigned long rank);
+
redisSortOperation *createSortOperation(int type, robj *pattern) {
redisSortOperation *so = zmalloc(sizeof(*so));
so->type = type;
return so;
}
-/* Return the value associated to the key with a name obtained
- * substituting the first occurence of '*' in 'pattern' with 'subst'.
+/* Return the value associated to the key with a name obtained using
+ * the following rules:
+ *
+ * 1) The first occurence of '*' in 'pattern' is substituted with 'subst'.
+ *
+ * 2) If 'pattern' matches the "->" string, everything on the left of
+ * the arrow is treated as the name of an hash field, and the part on the
+ * left as the key name containing an hash. The value of the specified
+ * field is returned.
+ *
+ * 3) If 'pattern' equals "#", the function simply returns 'subst' itself so
+ * that the SORT command can be used like: SORT key GET # to retrieve
+ * the Set/List elements directly.
+ *
* The returned object will always have its refcount increased by 1
* when it is non-NULL. */
robj *lookupKeyByPattern(redisDb *db, robj *pattern, robj *subst) {
- char *p, *f;
+ char *p, *f, *k;
sds spat, ssub;
- robj keyobj, fieldobj, *o;
+ robj *keyobj, *fieldobj = NULL, *o;
int prefixlen, sublen, postfixlen, fieldlen;
- /* Expoit the internal sds representation to create a sds string allocated on the stack in order to make this function faster */
- struct {
- int len;
- int free;
- char buf[REDIS_SORTKEY_MAX+1];
- } keyname, fieldname;
/* If the pattern is "#" return the substitution object itself in order
* to implement the "SORT ... GET #" feature. */
* a decoded object on the fly. Otherwise getDecodedObject will just
* increment the ref count, that we'll decrement later. */
subst = getDecodedObject(subst);
-
ssub = subst->ptr;
- if (sdslen(spat)+sdslen(ssub)-1 > REDIS_SORTKEY_MAX) return NULL;
+
+ /* If we can't find '*' in the pattern we return NULL as to GET a
+ * fixed key does not make sense. */
p = strchr(spat,'*');
if (!p) {
decrRefCount(subst);
}
/* Find out if we're dealing with a hash dereference. */
- if ((f = strstr(p+1, "->")) != NULL) {
- fieldlen = sdslen(spat)-(f-spat);
- /* this also copies \0 character */
- memcpy(fieldname.buf,f+2,fieldlen-1);
- fieldname.len = fieldlen-2;
+ if ((f = strstr(p+1, "->")) != NULL && *(f+2) != '\0') {
+ fieldlen = sdslen(spat)-(f-spat)-2;
+ fieldobj = createStringObject(f+2,fieldlen);
} else {
fieldlen = 0;
}
+ /* Perform the '*' substitution. */
prefixlen = p-spat;
sublen = sdslen(ssub);
- postfixlen = sdslen(spat)-(prefixlen+1)-fieldlen;
- memcpy(keyname.buf,spat,prefixlen);
- memcpy(keyname.buf+prefixlen,ssub,sublen);
- memcpy(keyname.buf+prefixlen+sublen,p+1,postfixlen);
- keyname.buf[prefixlen+sublen+postfixlen] = '\0';
- keyname.len = prefixlen+sublen+postfixlen;
- decrRefCount(subst);
+ postfixlen = sdslen(spat)-(prefixlen+1)-(fieldlen ? fieldlen+2 : 0);
+ keyobj = createStringObject(NULL,prefixlen+sublen+postfixlen);
+ k = keyobj->ptr;
+ memcpy(k,spat,prefixlen);
+ memcpy(k+prefixlen,ssub,sublen);
+ memcpy(k+prefixlen+sublen,p+1,postfixlen);
+ decrRefCount(subst); /* Incremented by decodeObject() */
/* Lookup substituted key */
- initStaticStringObject(keyobj,((char*)&keyname)+(sizeof(struct sdshdr)));
- o = lookupKeyRead(db,&keyobj);
- if (o == NULL) return NULL;
+ o = lookupKeyRead(db,keyobj);
+ if (o == NULL) goto noobj;
- if (fieldlen > 0) {
- if (o->type != REDIS_HASH || fieldname.len < 1) return NULL;
+ if (fieldobj) {
+ if (o->type != REDIS_HASH) goto noobj;
/* Retrieve value from hash by the field name. This operation
* already increases the refcount of the returned object. */
- initStaticStringObject(fieldobj,((char*)&fieldname)+(sizeof(struct sdshdr)));
- o = hashTypeGetObject(o, &fieldobj);
+ o = hashTypeGetObject(o, fieldobj);
} else {
- if (o->type != REDIS_STRING) return NULL;
+ if (o->type != REDIS_STRING) goto noobj;
/* Every object that this function returns needs to have its refcount
* increased. sortCommand decreases it again. */
incrRefCount(o);
}
-
+ decrRefCount(keyobj);
+ if (fieldobj) decrRefCount(fieldobj);
return o;
+
+noobj:
+ decrRefCount(keyobj);
+ if (fieldlen) decrRefCount(fieldobj);
+ return NULL;
}
/* sortCompare() is used by qsort in sortCommand(). Given that qsort_r with
/* Lookup the key to sort. It must be of the right types */
sortval = lookupKeyRead(c->db,c->argv[1]);
- if (sortval && sortval->type != REDIS_SET && sortval->type != REDIS_LIST &&
- sortval->type != REDIS_ZSET)
+ if (sortval && sortval->type != REDIS_SET &&
+ sortval->type != REDIS_LIST &&
+ sortval->type != REDIS_ZSET)
{
addReply(c,shared.wrongtypeerr);
return;
* Operations can be GET/DEL/INCR/DECR */
operations = listCreate();
listSetFreeMethod(operations,zfree);
- j = 2;
+ j = 2; /* options start at argv[2] */
/* Now we need to protect sortval incrementing its count, in the future
* SORT may have options able to overwrite/delete keys during the sorting
j++;
}
+ /* For the STORE option, or when SORT is called from a Lua script,
+ * we want to force a specific ordering even when no explicit ordering
+ * was asked (SORT BY nosort). This guarantees that replication / AOF
+ * is deterministic.
+ *
+ * However in the case 'dontsort' is true, but the type to sort is a
+ * sorted set, we don't need to do anything as ordering is guaranteed
+ * in this special case. */
+ if ((storekey || c->flags & REDIS_LUA_CLIENT) &&
+ (dontsort && sortval->type != REDIS_ZSET))
+ {
+ /* Force ALPHA sorting */
+ dontsort = 0;
+ alpha = 1;
+ sortby = NULL;
+ }
+
/* Destructively convert encoded sorted sets for SORT. */
if (sortval->type == REDIS_ZSET)
zsetConvert(sortval, REDIS_ENCODING_SKIPLIST);
- /* Load the sorting vector with all the objects to sort */
+ /* Objtain the length of the object to sort. */
switch(sortval->type) {
case REDIS_LIST: vectorlen = listTypeLength(sortval); break;
case REDIS_SET: vectorlen = setTypeSize(sortval); break;
case REDIS_ZSET: vectorlen = dictSize(((zset*)sortval->ptr)->dict); break;
default: vectorlen = 0; redisPanic("Bad SORT type"); /* Avoid GCC warning */
}
+
+ /* Perform LIMIT start,count sanity checking. */
+ start = (limit_start < 0) ? 0 : limit_start;
+ end = (limit_count < 0) ? vectorlen-1 : start+limit_count-1;
+ if (start >= vectorlen) {
+ start = vectorlen-1;
+ end = vectorlen-2;
+ }
+ if (end >= vectorlen) end = vectorlen-1;
+
+ /* Optimization:
+ *
+ * 1) if the object to sort is a sorted set.
+ * 2) There is nothing to sort as dontsort is true (BY <constant string>).
+ * 3) We have a LIMIT option that actually reduces the number of elements
+ * to fetch.
+ *
+ * In this case to load all the objects in the vector is a huge waste of
+ * resources. We just allocate a vector that is big enough for the selected
+ * range length, and make sure to load just this part in the vector. */
+ if (sortval->type == REDIS_ZSET &&
+ dontsort &&
+ (start != 0 || end != vectorlen-1))
+ {
+ vectorlen = end-start+1;
+ }
+
+ /* Load the sorting vector with all the objects to sort */
vector = zmalloc(sizeof(redisSortObject)*vectorlen);
j = 0;
j++;
}
setTypeReleaseIterator(si);
+ } else if (sortval->type == REDIS_ZSET && dontsort) {
+ /* Special handling for a sorted set, if 'dontsort' is true.
+ * This makes sure we return elements in the sorted set original
+ * ordering, accordingly to DESC / ASC options.
+ *
+ * Note that in this case we also handle LIMIT here in a direct
+ * way, just getting the required range, as an optimization. */
+
+ zset *zs = sortval->ptr;
+ zskiplist *zsl = zs->zsl;
+ zskiplistNode *ln;
+ robj *ele;
+ int rangelen = vectorlen;
+
+ /* Check if starting point is trivial, before doing log(N) lookup. */
+ if (desc) {
+ long zsetlen = dictSize(((zset*)sortval->ptr)->dict);
+
+ ln = zsl->tail;
+ if (start > 0)
+ ln = zslGetElementByRank(zsl,zsetlen-start);
+ } else {
+ ln = zsl->header->level[0].forward;
+ if (start > 0)
+ ln = zslGetElementByRank(zsl,start+1);
+ }
+
+ while(rangelen--) {
+ redisAssertWithInfo(c,sortval,ln != NULL);
+ ele = ln->obj;
+ vector[j].obj = ele;
+ vector[j].u.score = 0;
+ vector[j].u.cmpobj = NULL;
+ j++;
+ ln = desc ? ln->backward : ln->level[0].forward;
+ }
+ /* The code producing the output does not know that in the case of
+ * sorted set, 'dontsort', and LIMIT, we are able to get just the
+ * range, already sorted, so we need to adjust "start" and "end"
+ * to make sure start is set to 0. */
+ end -= start;
+ start = 0;
} else if (sortval->type == REDIS_ZSET) {
dict *set = ((zset*)sortval->ptr)->dict;
dictIterator *di;
}
}
- /* We are ready to sort the vector... perform a bit of sanity check
- * on the LIMIT option too. We'll use a partial version of quicksort. */
- start = (limit_start < 0) ? 0 : limit_start;
- end = (limit_count < 0) ? vectorlen-1 : start+limit_count-1;
- if (start >= vectorlen) {
- start = vectorlen-1;
- end = vectorlen-2;
- }
- if (end >= vectorlen) end = vectorlen-1;
-
- server.sort_dontsort = dontsort;
if (dontsort == 0) {
server.sort_desc = desc;
server.sort_alpha = alpha;
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