Aerospike 读写过程中对partition tree的引用计数的处理-CFANZ编程社区

as_tsvc_process_transaction：
    as_partition_reserve_write or as_partition_reserve_read
        pthread_mutex_lock(&p->lock);
        ...
        partition_reserve_lockfree(p, ns, rsv);
        |--cf_rc_reserve(p->vp);
        pthread_mutex_unlock(&p->lock);
        ...
    if (is_write) {
        if (as_transaction_is_delete(tr)) {
            status = as_delete_start(tr);
        }else if (tr->origin == FROM_IUDF || as_transaction_is_udf(tr)) {
            status = as_udf_start(tr);
        }else {
            status = as_write_start(tr);
        }
    }else {
        status = as_read_start(tr);
    }
    switch (status) {
    case TRANS_DONE_ERROR:
    case TRANS_DONE_SUCCESS:
    // Done, response already sent - free msg & release reservation.
        as_partition_release(&tr->rsv);
        break;
    case TRANS_IN_PROGRESS:
    // Don't free msg or release reservation - both owned by rw_request.
        free_msgp = false;
        break;
    case TRANS_WAITING:
    // Will be re-queued - don't free msg, but release reservation.
        free_msgp = false;
        as_partition_release(&tr->rsv);
        break;
    default:
        cf_crash(AS_TSVC, "invalid transaction status %d", status);
        break;
    }

1、事务处理流程一

thr_demarshal:
    as_tsvc_process_transaction(&tr);

2、事务处理流程二

thr_demarshal:
    as_batch_queue_task(&tr)->as_tsvc_process_transaction(&tr);
                            ->as_tsvc_enqueue(&tr);

3、事务处理流程三

thr_demarshal:
    as_tsvc_enqueue(&tr);
run_tsvc:
    cf_queue *q = g_transaction_queues[qid];
    while (true) {
        cf_queue_pop(q, &tr, CF_QUEUE_FOREVER);
        as_tsvc_process_transaction(&tr);
    }

1、partition_reserve_lockfree该函数会对partition tree引用计数加1

2、事务处理的几个流程最终都会调用as_tsvc_process_transaction进行事务处理

先对partition的tree引用计数加1。操作结束后根据as_delete_start | as_write_start

| as_read_start | as_udf_start的返回值对引用计数减一：

1）TRANS_DONE_ERROR | TRANS_DONE_SUCCESS ：对引用计数减一

2）TRANS_IN_PROGRESS：引用计数不减一

3）TRANS_WAITING：引用计数减一

4）else：也不减一

3、as_write_start返回TRANS_DONE_ERROR

1）dupl写失败，将rw从g_rw_request_hash表删除

4、as_write_start返回TRANS_IN_PROGRESS

1）dupl写成功

3和4都需要写dupl情况，最后直接返回。5之后都是不需要dupl情况：

5、as_write_start返回TRANS_IN_PROGRESS：write_master写成功，之后开始写replica
6、write_master写成功返回TRANS_IN_PROGRESS，否则返回TRANS_DONE_ERROR
1）当返回TRANS_DONE_ERROR时，会将rw从g_rw_request_hash表删除并返回TRANS_DONE_ERROR
2）write_master写成功返回TRANS_IN_PROGRESS时，如果不需要写replica，返回TRANS_DONE_SUCCESS
3）否则初始化写replica的rw失败返回TRANS_DONE_ERROR

总结：
1、as_write_start函数只有写成功后，并需要写replica时才会对partition tree 的引用计数不减一。
2、目标节点write_replica过程中会对partition tree引用计数加一，结束后减一
3、repl_write_handle_ack接收到replica写完成的ACK后调用rw_request_release(rw)->rw_request_destroy(rw)
->as_partition_release(&rw->rsv);将partition tree的引用计数减一