+1 on a replication heartbeat w/configurable heartbeat time. We'd want to issue a heartbeat pules every 1 sec in our environment to measure *true* replication latency.
Jeremy On Fri, Jan 22, 2010 at 6:21 AM, Kristian Nielsen <kniel...@knielsen-hq.org>wrote: > The three companies Continuent, Codership, and Monty Program are planning > to > start working on some enhancements to the replication system in MariaDB, > together with anyone interested in joining in. > > At this stage, there are no fixed directions for the project, and to do > this > in as open a way possible with the maximum community involvement and > interest, > we agreed to start with an email discussion on the maria-develop...@mailing > list. So consider it started! > > The plan so far is: > > 1) The parties taking this initiative, MP, Continuent, and Codership, > present > their own ideas in this thread on maria-developers@ (and everyone else who > wants to chime in at this stage). > > 2) Once we have some concrete suggestions as a starting point, we use this > to > reach out in a broader way with some blog posts on planetmysql / > planetmariadb > to encourage further input and discussions for possible directions of the > project. Eventually we want to end up with a list of the most important > goals > and a possible roadmap for replication enhancements. > > (It is best to have something concrete as a basis of a broad community > discussion/process). > > To start of, here are some points of interest that I collected. Everyone > please chime in with your own additional points, as well as comments and > further details on these one. > > Three areas in particular seem to be of high interest in the community > currently (not excluding any other areas): > > - High Availability > * Most seems to focus on building HA solutions on top of MySQL > replication, eg. MMM and Tungsten. > * For this project, seems mainly to be to implement improvements to > replication that help facilitate improving these on-top HA solutions. > * Tools to automate (or help automate) failover from a master. > * Better facilities to do initial setup of new slave without downtime, > or > re-sync of an old master or slave that has been outside of the > replication topology for some period of time. > > - Performance, especially scalability > * Multi-threaded slave SQL thread. > * Store the binlog inside a transactional engine (eg. InnoDB) to reduce > I/O, solve problems like group commit, and simplify crash recovery. > > - More pluggable replication > * Make the replication code and APIs be more suitable for people to > build > extra functionality into or on top of the stock MySQL replication. > * Better documentation of C++ APIs and binlog format. > * Adding extra information to binlog that can be useful for non-standard > replication stuff. For example column names (for RBR), checksums. > * Refactoring the server code to be more modular with APIs more suitable > for external usage. > * Add support for replication plugins, types to be determined. For > example > binlog filtering plugins? > > It is also very important to consider the work that the replication team at > MySQL is doing (and has done). I found a good deal of interesting > information > about this here: > > > http://forge.mysql.com/wiki/MySQL_Replication:_Walk-through_of_the_new_5.1_and_6.0_features > ) > > This describes a number of 6.0/5.4 and preview features that we could merge > and/or contribute to. Here are the highlights that I found: > > - Features included in 6.0/5.4 (which are cancelled I think, but > presumably > this will go in a milestone release): > * CHANGE MASTER ... IGNORE_SERVER_IDS for better support of circular > replication. > * Replication heartbeat. > * sync_relay_log_info, sync_master_info, sync_relay_log, > relay_log_recovery > for crash recovery on slave. > * Binlog Performance Optimization (lock contention improvement). > * Semi-synchronous Replication, with Pluggable Replication Architecture. > http://forge.mysql.com/wiki/ReplicationFeatures/SemiSyncReplication > > - Feature previews: > * Parallel slave application: WL#4648 > http://forge.mysql.com/wiki/ReplicationFeatures/ParallelSlave > * Time-delayed replication: WL#344 > http://forge.mysql.com/wiki/ReplicationFeatures/DelayedReplication > * Scriptable Replication: WL#4008 > http://forge.mysql.com/wiki/ReplicationFeatures/ScriptableReplication > * Synchronous Replication. > > Drizzle is also doing work on a new replication system. I read through the > series of blog posts that Jay Pipes wrote on this subject. They mostly deal > with how this is designed in terms of the Drizzle server code, and is low > on > detail about how the replication will actually work (the only thing I could > really extract was that it is a form of row-based replication). If someone > has > links to information about this that I missed, it could be interesting. > > Let the discussion begin! > > - Kristian. > > _______________________________________________ > Mailing list: > https://launchpad.net/~maria-developers<https://launchpad.net/%7Emaria-developers> > Post to : maria-developers@lists.launchpad.net > Unsubscribe : > https://launchpad.net/~maria-developers<https://launchpad.net/%7Emaria-developers> > More help : https://help.launchpad.net/ListHelp >
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