文件存储协议

commitlog存储协议

CommitLog.doAppend(单条)

# ipv4: 8字节  ipv6:20字节
int bornHostLength = (sysflag & MessageSysFlag.BORNHOST_V6_FLAG) == 0 ? 4 + 4 : 16 + 4;
# ipv4: 8字节  ipv6:20字节
int storeHostLength = (sysflag & MessageSysFlag.STOREHOSTADDRESS_V6_FLAG) == 0 ? 4 + 4 : 16 + 4;

// 1 TOTALSIZE 消息大小  4byte
this.msgStoreItemMemory.putInt(msgLen);
// 2 MAGICCODE 开头魔幻数字 4byte daa320a7
this.msgStoreItemMemory.putInt(CommitLog.MESSAGE_MAGIC_CODE);
// 3 BODYCRC 消息体的BODY CRC，broker重启会校验 4byte
this.msgStoreItemMemory.putInt(msgInner.getBodyCRC());
// 4 QUEUEID 队列编号，queueId  4byte
this.msgStoreItemMemory.putInt(msgInner.getQueueId());
// 5 FLAG 这个标志值rocketmq不做处理，只存储后透传
this.msgStoreItemMemory.putInt(msgInner.getFlag());
// 6 QUEUEOFFSET  topic-queueId对应的队列数目
this.msgStoreItemMemory.putLong(queueOffset);
// 7 PHYSICALOFFSET  真实的地址偏移，包括所有文件的总偏移
this.msgStoreItemMemory.putLong(fileFromOffset + byteBuffer.position());
// 8 SYSFLAG
this.msgStoreItemMemory.putInt(msgInner.getSysFlag());
// 9 BORNTIMESTAMP
this.msgStoreItemMemory.putLong(msgInner.getBornTimestamp());
// 10 BORNHOST
this.resetByteBuffer(bornHostHolder, bornHostLength);
this.msgStoreItemMemory.put(msgInner.getBornHostBytes(bornHostHolder));
// 11 STORETIMESTAMP
this.msgStoreItemMemory.putLong(msgInner.getStoreTimestamp());
// 12 STOREHOSTADDRESS
this.resetByteBuffer(storeHostHolder, storeHostLength);
this.msgStoreItemMemory.put(msgInner.getStoreHostBytes(storeHostHolder));
// 13 RECONSUMETIMES
this.msgStoreItemMemory.putInt(msgInner.getReconsumeTimes());
// 14 Prepared Transaction Offset
this.msgStoreItemMemory.putLong(msgInner.getPreparedTransactionOffset());
// 15 BODY
this.msgStoreItemMemory.putInt(bodyLength);
if (bodyLength > 0)
	this.msgStoreItemMemory.put(msgInner.getBody());
// 16 TOPIC
this.msgStoreItemMemory.put((byte) topicLength);
this.msgStoreItemMemory.put(topicData);
// 17 PROPERTIES
this.msgStoreItemMemory.putShort((short) propertiesLength);
if (propertiesLength > 0)
	this.msgStoreItemMemory.put(propertiesData);

final long beginTimeMills = CommitLog.this.defaultMessageStore.now();
// Write messages to the queue buffer
byteBuffer.put(this.msgStoreItemMemory.array(), 0, msgLen);