RocketMQ 刷盘机制BUG踩坑——可能引起消息丢失

上文说到dledger模式有bug，于是还是踏实考察master-slave或HA的架构。最近看源码发现一个严重的bug，可能导致消息丢失。

具体分析过程有机会再详写，直接看MappedFile.java的flush方法代码

 public int flush(final int flushLeastPages) {
        if (this.isAbleToFlush(flushLeastPages)) {
            if (this.hold()) {
                int value = getReadPosition();

                try {
                    //We only append data to fileChannel or mappedByteBuffer, never both.
                    if (writeBuffer != null || this.fileChannel.position() != 0) {
                        this.fileChannel.force(false);
                    } else {
                        this.mappedByteBuffer.force();
                    }
                } catch (Throwable e) {
                    log.error("Error occurred when force data to disk.", e);
                }

                this.flushedPosition.set(value);
                this.release();
            } else {
                log.warn("in flush, hold fai