The main code is at Learner.java syncWithLeader like this:
if (qp.getType() == Leader.DIFF) {
LOG.info("Getting a diff from the leader 0x{}",
Long.toHexString(qp.getZxid()));
snapshotNeeded = false;
}
case Leader.COMMITANDACTIVATE:
if (!writeToTxnLog) {
if (pif.hdr.getZxid() != qp.getZxid()) {
LOG.warn("Committing " + qp.getZxid() + ", but next
proposal is " + pif.hdr.getZxid());
} else {
zk.processTxn(pif.hdr, pif.rec);
packetsNotCommitted.remove();
}
} else {
packetsCommitted.add(qp.getZxid());
}
break;
zk.startup();//this will create the processor chain,and waiting
request will be processed after the zk startup
if (zk instanceof FollowerZooKeeperServer) {
FollowerZooKeeperServer fzk = (FollowerZooKeeperServer)zk;
for(PacketInFlight p: packetsNotCommitted) {
fzk.logRequest(p.hdr, p.rec);
}
for(Long zxid: packetsCommitted) {
fzk.commit(zxid);
}
}
yuzhou li <[email protected]> 于2018年6月14日周四 下午1:47写道：
>
> Hi,everyone.
> I git pull the tag release-3.5.4 from github. Before I read the
> 3.4.6 version code, I found 3.5.4 has some changes when the learner
> synchronzied with leader.
> If using DIFF way to synchronize histories, the follower or observer
> will put the data in a queue, then start zkServer, then get all data
> from the queue, and process the data as a normol request,after all
> data is processd, the server is synchronized with leader completely.
> But at zkServe start moment, the client request can be process by this
> server,but this server has no data because the data is stored at the
> queue currently, so the client will read dirty data.
> Does this situation will happend?Or there is some point I has not find?
