Function clientsCronResizeQueryBuffer

src/server.cpp:1795–1834

The client query buffer is an sds.c string that can end with a lot of * free space not used, this function reclaims space if needed. * * The function always returns 0 as it never terminates the client. */

 *
 * The function always returns 0 as it never terminates the client. */
int clientsCronResizeQueryBuffer(client *c) {
    AssertCorrectThread(c);
    size_t querybuf_size = sdsAllocSize(c->querybuf);
    time_t idletime = g_pserver->unixtime - c->lastinteraction;

    /* There are two conditions to resize the query buffer:
     * 1) Query buffer is > BIG_ARG and too big for latest peak.
     * 2) Query buffer is > BIG_ARG and client is idle. */
    if (querybuf_size > PROTO_MBULK_BIG_ARG &&
         ((querybuf_size/(c->querybuf_peak+1)) > 2 ||
          idletime > 2))
    {
        /* Only resize the query buffer if it is actually wasting
         * at least a few kbytes. */
        if (sdsavail(c->querybuf) > 1024*4) {
            c->querybuf = sdsRemoveFreeSpace(c->querybuf);
        }
    }
    /* Reset the peak again to capture the peak memory usage in the next
     * cycle. */
    c->querybuf_peak = 0;

    /* Clients representing masters also use a "pending query buffer" that
     * is the yet not applied part of the stream we are reading. Such buffer
     * also needs resizing from time to time, otherwise after a very large
     * transfer (a huge value or a big MIGRATE operation) it will keep using
     * a lot of memory. */
    if (c->flags & CLIENT_MASTER) {
        /* There are two conditions to resize the pending query buffer:
         * 1) Pending Query buffer is > LIMIT_PENDING_QUERYBUF.
         * 2) Used length is smaller than pending_querybuf_size/2 */
        size_t pending_querybuf_size = sdsAllocSize(c->pending_querybuf);
        if(pending_querybuf_size > LIMIT_PENDING_QUERYBUF &&
           sdslen(c->pending_querybuf) < (pending_querybuf_size/2))
        {
            c->pending_querybuf = sdsRemoveFreeSpace(c->pending_querybuf);
        }
    }
    return 0;
}

SymVer parseVersion(const char *version)
{