Redis教程

redis集群模式-key分配一个slot

本文主要是介绍redis集群模式-key分配一个slot,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!

集群模式key的含有{}的情况会计算{}中的crc16|64的值。如果用{prefix}做前缀会分配到一个slot。

/* -----------------------------------------------------------------------------
 * Key space handling
 * -------------------------------------------------------------------------- */

/* We have 16384 hash slots. The hash slot of a given key is obtained
 * as the least significant 14 bits of the crc16 of the key.
 *
 * However if the key contains the {...} pattern, only the part between
 * { and } is hashed. This may be useful in the future to force certain
 * keys to be in the same node (assuming no resharding is in progress). */
static unsigned int clusterManagerKeyHashSlot(char *key, int keylen) {
    int s, e; /* start-end indexes of { and } */

    for (s = 0; s < keylen; s++)
        if (key[s] == '{') break;

    /* No '{' ? Hash the whole key. This is the base case. */
    if (s == keylen) return crc16(key,keylen) & 0x3FFF;

    /* '{' found? Check if we have the corresponding '}'. */
    for (e = s+1; e < keylen; e++)
        if (key[e] == '}') break;

    /* No '}' or nothing between {} ? Hash the whole key. */
    if (e == keylen || e == s+1) return crc16(key,keylen) & 0x3FFF;

    /* If we are here there is both a { and a } on its right. Hash
     * what is in the middle between { and }. */
    return crc16(key+s+1,e-s-1) & 0x3FFF;
}
这篇关于redis集群模式-key分配一个slot的文章就介绍到这儿,希望我们推荐的文章对大家有所帮助,也希望大家多多支持为之网!