Function rdbSaveStreamPEL

app/redis-6.2.6/src/rdb.c:718–757

This helper function serializes a consumer group Pending Entries List (PEL) * into the RDB file. The 'nacks' argument tells the function if also persist * the informations about the not acknowledged message, or if to persist * just the IDs: this is useful because for the global consumer group PEL * we serialized the NACKs as well, but when serializing the local consumer * PELs we just add the

 * PELs we just add the ID, that will be resolved inside the global PEL to
 * put a reference to the same structure. */
ssize_t rdbSaveStreamPEL(rio *rdb, rax *pel, int nacks) {
    ssize_t n, nwritten = 0;

    /* Number of entries in the PEL. */
    if ((n = rdbSaveLen(rdb,raxSize(pel))) == -1) return -1;
    nwritten += n;

    /* Save each entry. */
    raxIterator ri;
    raxStart(&ri,pel);
    raxSeek(&ri,"^",NULL,0);
    while(raxNext(&ri)) {
        /* We store IDs in raw form as 128 big big endian numbers, like
         * they are inside the radix tree key. */
        if ((n = rdbWriteRaw(rdb,ri.key,sizeof(streamID))) == -1) {
            raxStop(&ri);
            return -1;
        }
        nwritten += n;

        if (nacks) {
            streamNACK *nack = ri.data;
            if ((n = rdbSaveMillisecondTime(rdb,nack->delivery_time)) == -1) {
                raxStop(&ri);
                return -1;
            }
            nwritten += n;
            if ((n = rdbSaveLen(rdb,nack->delivery_count)) == -1) {
                raxStop(&ri);
                return -1;
            }
            nwritten += n;
            /* We don't save the consumer name: we'll save the pending IDs
             * for each consumer in the consumer PEL, and resolve the consumer
             * at loading time. */
        }
    }
    raxStop(&ri);
    return nwritten;
}

/* Serialize the consumers of a stream consumer group into the RDB. Helper
 * function for the stream data type serialization. What we do here is to