当从设备的commitLog与主设备不匹配时，HA可能不可用

版本：4.3.4.4.0 当奴隶的机器坏了几天时，在机器修好后启动奴隶在这种情况下，master无法将commitLog数据发送到slave，这导致SYNC_master在向该代理发送消息时返回slave_NOT_AVAIABLE在master的broker.log中搜索，可以找到“Slave fall落后于master：xxx”

经过分析，我发现从方的commitLog偏移量在主方的commit Log中不存在，这导致主方getCommitLogData的偏移量超出范围返回null，然后只发送心跳

一些资源代码如下：

SelectMappedBufferResult selectResult = HAConnection.this.haService.getDefaultMessageStore().getCommitLogData(this.nextTransferFromWhere); if (selectResult != null) { int size = selectResult.getSize(); if (size > HAConnection.this.haService.getDefaultMessageStore().getMessageStoreConfig().getHaTransferBatchSize()) { size = HAConnection.this.haService.getDefaultMessageStore().getMessageStoreConfig().getHaTransferBatchSize(); }

                    long thisOffset = this.nextTransferFromWhere;
                    this.nextTransferFromWhere += size;

                    selectResult.getByteBuffer().limit(size);
                    this.selectMappedBufferResult = selectResult;

                    // Build Header
                    this.byteBufferHeader.position(0);
                    this.byteBufferHeader.limit(headerSize);
                    this.byteBufferHeader.putLong(thisOffset);
                    this.byteBufferHeader.putInt(size);
                    this.byteBufferHeader.flip();

                    this.lastWriteOver = this.transferData();
                } else {
                    service.getWaitNotifyObject().wakeupAll();
                    HAConnection.this.haService.getWaitNotifyObject().allWaitForRunning(100);
                }

我认为当master收到slaveRequestOffset时，计算nextTransfer FromWhere应该检查slaveRequest Offset是否合法，而不仅仅是

this.nextTransferFromWhere = HAConnection.this.slaveRequestOffset;

原提问者GitHub用户qsrg