Function memoryCommand

src/object.cpp:1400–1561

The memory command will eventually be a complete interface for the * memory introspection capabilities of Redis. * * Usage: MEMORY usage */

 *
 * Usage: MEMORY usage <key> */
void memoryCommand(client *c) {
    if (!strcasecmp(szFromObj(c->argv[1]),"help") && c->argc == 2) {
        const char *help[] = {
            "DOCTOR",
            "    Return memory problems reports.",
            "MALLOC-STATS"
            "    Return internal statistics report from the memory allocator.",
            "PURGE",
            "    Attempt to purge dirty pages for reclamation by the allocator.",
            "STATS",
            "    Return information about the memory usage of the server.",
            "USAGE <key> [SAMPLES <count>]",
            "    Return memory in bytes used by <key> and its value. Nested values are",
            "    sampled up to <count> times (default: 5).",
            NULL
        };
        addReplyHelp(c, help);
    } else if (!strcasecmp(szFromObj(c->argv[1]),"usage") && c->argc >= 3) {
        long long samples = OBJ_COMPUTE_SIZE_DEF_SAMPLES;
        for (int j = 3; j < c->argc; j++) {
            if (!strcasecmp(szFromObj(c->argv[j]),"samples") &&
                j+1 < c->argc)
            {
                if (getLongLongFromObjectOrReply(c,c->argv[j+1],&samples,NULL)
                     == C_ERR) return;
                if (samples < 0) {
                    addReplyErrorObject(c,shared.syntaxerr);
                    return;
                }
                if (samples == 0) samples = LLONG_MAX;
                j++; /* skip option argument. */
            } else {
                addReplyErrorObject(c,shared.syntaxerr);
                return;
            }
        }

        auto itr = c->db->find(c->argv[2]);
        if (itr == nullptr) {
            addReplyNull(c);
            return;
        }
        size_t usage = objectComputeSize(itr.val(),samples);
        usage += sdsZmallocSize(itr.key());
        usage += sizeof(dictEntry);
        addReplyLongLong(c,usage);
    } else if (!strcasecmp(szFromObj(c->argv[1]),"stats") && c->argc == 2) {
        struct redisMemOverhead *mh = getMemoryOverheadData();

        addReplyMapLen(c,25+mh->num_dbs);

        addReplyBulkCString(c,"peak.allocated");
        addReplyLongLong(c,mh->peak_allocated);

        addReplyBulkCString(c,"total.allocated");
        addReplyLongLong(c,mh->total_allocated);

        addReplyBulkCString(c,"startup.allocated");