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High Availability with MySQL Fabric: Part I

and  | May 15, 2014 |  Posted In: High-availability, Insight for DBAs, MySQL

In our previous post, we introduced the MySQL Fabric utility and said we would dig deeper into it. This post is the first part of our test of MySQL Fabric’s High Availability (HA) functionality. Today, we’ll review MySQL Fabric’s HA concepts, and then walk you through the setup of a 3-node cluster with one Primary and two […]

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How TokuMX Secondaries Work in Replication

 | April 15, 2014 |  Posted In: Tokutek, TokuView

As I’ve mentioned in previous posts, TokuMX replication differs quite a bit from MongoDB’s replication. The differences are large enough such that we’ve completely redone some of MongoDB’s existing algorithms. One such area is how secondaries apply oplog data from a primary. In this post, I’ll explain how. In designing how secondaries apply oplog data, […]

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On TokuMX Oplog, Tailable Cursors, and Concurrency

 | April 2, 2014 |  Posted In: Tokutek, TokuView

In a post last week, I described the difference in concurrency behavior between MongoDB’s oplog and TokuMX’s oplog. In short, here are the key differences: MongoDB protects access to the oplog with a database level reader/writer lock, whereas TokuMX does not. TokuMX can write data to the oplog concurrently, whereas MongoDB cannot. As a result, […]

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On TokuMX (and MongoDB) Replication and Transactions

 | March 28, 2014 |  Posted In: Tokutek, TokuView

In my last post, I describe the differences between a TokuMX oplog entry and a MongoDB oplog entry. One reason why the entries are so different is that TokuMX supports multi-statement and multi-document transactions. In this post, I want to elaborate on why multi-statement transactions cause changes to the oplog, and explain how we changed […]

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Comparing a TokuMX and MongoDB Oplog Entry

 | March 26, 2014 |  Posted In: Tokutek, TokuView

As I mentioned in my last post, TokuMX replication is completely incompatible with MongoDB replication. Replica sets (and sharded clusters, but that is for another blog) must be either entirely TokuMX or entirely MongoDB. This is by design. While elections and failover are basically the same, we have completely changed the oplog protocol. In the […]

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Why TokuMX Replication Differs from MongoDB Replication

 | March 24, 2014 |  Posted In: Tokutek, TokuView

MongoDB replication has some great features. As I discussed in my last post, MongoDB’s crash safety design is very elegant. In addition to that, MongoDB has automatic failover, parallel slave replication, and prefetch threads on secondaries. The latter, as Mark Callaghan points out, is similar to “InnoDB fake changes”, a feature that has helped Facebook […]

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My Favorite MongoDB Replication Feature: Crash Safety

 | March 18, 2014 |  Posted In: Tokutek, TokuView

At an extremely high level, replication in MongoDB and MySQL are similar. Both databases have exactly one machine, the primary (or master), that accepts writes from clients. With a single transaction (or atomic operation, in MongoDB’s case), the tables and oplog (or binary log in MySQL) are modified to reflect the change. The log captures […]

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What’s new in TokuMX 1.4, Part 3: Optimized updates

 | February 19, 2014 |  Posted In: Tokutek, TokuView

We just released version 1.4.0 of TokuMX, our high-performance distribution of MongoDB. There are a lot of improvements in this version (release notes), the most of any release yet. In this series of blog posts, we describe the most interesting changes and how they’ll affect users. In TokuMX 1.4.0, we improved performance by making two […]

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What’s new in TokuMX 1.4, Part 2: Partitioned oplog

 | February 18, 2014 |  Posted In: Tokutek, TokuView

We just released version 1.4.0 of TokuMX, our high-performance distribution of MongoDB. There are a lot of improvements in this version (release notes), the most of any release yet. In this series of blog posts, we describe the most interesting changes and how they’ll affect users. In MongoDB, the replication oplog is a capped collection, […]

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