MySQL Conf 2008 – MySQL Replication (Day 1)

Author Michael Tougeron on April 14, 2008

Posted under Events, mysql and tagged with , , ,

I started off the MySQL Conference 2008 with the replication tutorial. I’m hoping that there will be some good tidbits in the second half of the session. I’m almost positive the first part will be refresher and standard replication stuff.

I really wanted to do the MySQL Proxy session, but that is an all-day thing and I’d miss the Memcached session. In hindsight, I’m probably going to regret that decision, but we’ll see. I can always do Proxy next year. πŸ™‚

10:00am: So far pretty much all refresher. Some people have asked some good questions about the relay logs and replication lag. Unfortunately, none of it is particularly helpful. I don’t understand why MySQL doesn’t enable a way to do master-master replication reliably outside of NDB. In my opinion, NDB, is not an appropriate solution for most websites. Having to take down the entire cluster to alter a table would not be acceptable. πŸ™

10:45am: Not sure if it is my laptop or the wireless network, but my connection/authorization never seems to carry over from when I log in/out of the laptop. I have to disconnect from the wireless auto-reconnect and connect again manually in order to get on the Internet. I wonder if anyone else is having this problem?

10:45am: One of the recommend ways for doing HA master/master is to use a shared disk array. The section would be to put a virtual IP in front of a heartbeat monitor in front of two MySQL servers configured the same. If they shared the same disk array, then the bin-log will be the same for both servers. The heartbeat monitor then sends the traffic to mas1 until it finds that it is no longer online. Then the traffic goes to mas2 automatically. When mas1 comes back online, the heartbeat monitor sends the traffic back automatically. Since mas2 is no longer reading/writing to the db tables, there shouldn’t be any corruption. Behind the mas1/mas2 is another virtual IP tied to the same heartbeat monitor. That way the slaves will also stay online. This sounds like it will handle many of the scenarios where you need HA master/master. The only thing I still see missing is the ability to alter tables without bringing down the tier like you can with m/cluster. [ m/cluster is a product by Continuent for HA synchronous replication. Of course, that product is EOL and their new product doesn’t allow this either. πŸ™ ]

11:00am: Federated databases are good for joining two sets of data to another db server. I guess I always misunderstood how that works. This seems like it’d be a good way to hook up user information with community (forums) data. I wonder what the performance costs are?

11:15am: Row-based replication in 5.1 paves the way for future replication enhancements such as conflict detection & conflict resolution. As well as multi-channel replication and horizontal partioning. Multi-channel replication would be really cool. It is such a pain when replication lags and this could go a long way to help fight that. You cannot do master filtering for individual tables with row-based. I wonder why that is?

12:00pm: I don’t know why MySQL keeps pushing NDB as the end-all solution to replication problems. Yes it can deal with a lot of the replication issues, but it has several other issues that make it a bad (or at least not optimal) solution.

12:05pm: eek, running out of battery power. I have 18 minutes left… Should be able to make it until lunch. Maybe…

12:20: That’s about it. Q&A now, but I’m headed out to find a lunch table near power. πŸ˜›

Posted under Events, mysql

This post was written by Michael Tougeron on April 14, 2008

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