… activities are overloading the system causing user experience to degrade. The first thing you need to know it is not MySQL problem… typically need to reduce concurrency to where it does not overload the system. Unless it is really time critical process I… heavily writing to database. Introduce Throttling Sometimes even single process overloads system too much in this case throttling by having relatively…
Post: Managing Slave Lag with MySQL Replication
October 12, 2007 By 15 Comments
… falls behind and why we see those lag spikes: Slave Server Load – MySQL Replication goes in single thread so it is really…. If you get 100 active queries running on the slave overloading it, slave thread will most likely will not get CPU or Disk…% of the master capacity to the slave. So watch your replication and see if it getting overloaded. Typically you will see it…
Post: The Math of Automated Failover
September 18, 2012 By 9 Comments
… apply them to MySQL replication we can use these simplified principles – we only will failover from Master to Slave but never fail… and the box is overloaded and “goes down”. As we fail over another server goes down with overload the same way. This… the art high availability solutions for MySQL such as Clustrix, Tungsten Replicator, PRM, Percona XtraDB Cluster, MySQL and DRBD as well as…
Post: Thoughts on MySQL Replication
July 7, 2006 By 18 Comments
… 60% of resources used by the slaves to handle writes. You might have 10 slaves so read load might not be the…’re accessing to be cached in memory by MySQL cache or OS cache. As slaves replicate the same data and often queried… want to structure replication with median servers to avoid master overload in such case. – No long queries – As I already wrote…
Post: Automation: A case for synchronous replication
September 19, 2012 By 2 Comments
… of the node and do not send new requests to overloaded node as well as use other techniques which keep the… tricky. Not only Failover process for MySQL replication is tricky it can be long – consider slaves lagging and need few minutes to…-synchronous replication available in MySQL 5.5 does not solves these problems. It helps to ensure the slave can be cought up…
Post: Fighting MySQL Replication Lag
September 22, 2008 By 7 Comments
… full table scan in MySQL 5.0 (even if there are no spam posts) which will load slave significantly. You can replace… allows it. In MySQL 5.1 with row level replication you will not have selection process running on SLAVE but it will… cases when you need this functionality. Finally you should not overload your replication – Quite typically I see replication lagging when batch…
Post: Implementing efficient counters with MySQL
July 1, 2007 By 16 Comments
… becomes very easy to overload the replication, especially as it has to serialize transactions on the slave which could be executed in… real-time counters very efficiently pushing few updates back to MySQL server. If you rather use existing solutions you can use memcache + another mysql instance (or simply the database which is not replicated) to…
Post: State of the art: Galera - synchronous replication for InnoDB
October 27, 2009 By 15 Comments
…Seppo Jaakola was presenting “Galera: Multi-Master Synchronous MySQL Replication Clusters”. It was impressed as I… state, there is no “slave behind”. When you read from any slave, you read actual data…. in the chain. So if one node gets overloaded and performance degrades, the same happens with whole …
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
…The great things about objects is you can easily overload > methods and get debugging and profiling tools, … traditional database background. > Things are different with MySQL. Good design will help dictate how many … those changes are making it to the slave(s). Like any other decision in database …
Post: Why you don't want to shard.
August 6, 2009 By 34 Comments
… 10 controller w/battery backed write cache, the slave delay problem is actually very hard to solve…. busy tables, and move them onto their own MySQL server. Partition-by-function keeps the architecture… far exceed average users and some servers are overloaded while others are not.(Tip: There are a …
