Function objectCommand

src/object.cpp:1338–1394

Object command allows to inspect the internals of a Redis Object. * Usage: OBJECT */

/* Object command allows to inspect the internals of a Redis Object.
 * Usage: OBJECT <refcount|encoding|idletime|freq> <key> */
void objectCommand(client *c) {
    robj_roptr o;

    if (c->argc == 2 && !strcasecmp(szFromObj(c->argv[1]),"help")) {
        const char *help[] = {
"ENCODING <key>",
"    Return the kind of internal representation used in order to store the value",
"    associated with a <key>.",
"FREQ <key>",
"    Return the access frequency index of the <key>. The returned integer is",
"    proportional to the logarithm of the recent access frequency of the key.",
"IDLETIME <key>",
"    Return the idle time of the <key>, that is the approximated number of",
"    seconds elapsed since the last access to the key.",
"REFCOUNT <key>",
"    Return the number of references of the value associated with the specified",
"    <key>.",
NULL
        };
        addReplyHelp(c, help);
    } else if (!strcasecmp(szFromObj(c->argv[1]),"refcount") && c->argc == 3) {
        if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.null[c->resp]))
                == nullptr) return;
        addReplyLongLong(c,o->getrefcount(std::memory_order_relaxed));
    } else if (!strcasecmp(szFromObj(c->argv[1]),"encoding") && c->argc == 3) {
        if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.null[c->resp]))
                == nullptr) return;
        addReplyBulkCString(c,strEncoding(o->encoding));
    } else if (!strcasecmp(szFromObj(c->argv[1]),"idletime") && c->argc == 3) {
        if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.null[c->resp]))
                == nullptr) return;
        if (g_pserver->maxmemory_policy & MAXMEMORY_FLAG_LFU) {
            addReplyError(c,"An LFU maxmemory policy is selected, idle time not tracked. Please note that when switching between policies at runtime LRU and LFU data will take some time to adjust.");
            return;
        }
        addReplyLongLong(c,estimateObjectIdleTime(o)/1000);
    } else if (!strcasecmp(szFromObj(c->argv[1]),"freq") && c->argc == 3) {
        if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.null[c->resp]))
                == nullptr) return;
        if (!(g_pserver->maxmemory_policy & MAXMEMORY_FLAG_LFU)) {
            addReplyError(c,"An LFU maxmemory policy is not selected, access frequency not tracked. Please note that when switching between policies at runtime LRU and LFU data will take some time to adjust.");
            return;
        }
        /* LFUDecrAndReturn should be called
         * in case of the key has not been accessed for a long time,
         * because we update the access time only
         * when the key is read or overwritten. */
        addReplyLongLong(c,LFUDecrAndReturn(o.unsafe_robjcast()));
    } else if (!strcasecmp(szFromObj(c->argv[1]), "lastmodified") && c->argc == 3) {
        if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.null[c->resp]))
                == nullptr) return;
        uint64_t mvcc = mvccFromObj(o);
        addReplyLongLong(c, (g_pserver->mstime - (mvcc >> MVCC_MS_SHIFT)) / 1000);
    } else {
        addReplySubcommandSyntaxError(c);
    }
}