I recently hosted hosting a webinar which explained what MySQL Clusrter is, what it can deliver and what the latest developments were. The “Discover the latest MySQL Cluster Developments” webinar is now available to view here (http://www.mysql.com/news-and-events/web-seminars/discover-the-latest-mysql-cluster-developments/" target="_blank). At the end of this article you’ll find a full transcript of the Q&A from the live session.
View this webinar to learn how MySQL Cluster 7.3, the latest GA release, enables developer agility by making it far simpler and faster to build your products and web-based applications with MySQL Cluster. You’ll also learn how MySQL Cluster and its linear scalability, 99.999% uptime, real-time responsiveness, and ability to perform over 1 BILLION Writes per Minute can help your products and applications meet the needs of the most demanding markets. MySQL Cluster combines these capabilities and the affordability of open source, making it well suited for use as an embedded database.
In this replay you’ll learn about the following MySQL Cluster capabilities, including the latest innovations in the 7.3 GA release:
- Auto-sharding (partitioning) across commodity hardware for extreme read and write scalability
- Cross-data center geographic synchronous and asynchronous replication
- Online scaling and schema upgrades, now with improved Connection Thread Scalability
- Real-time optimizations for ultra-low, predictable latency
- Foreign Key Support for tight referential integrity
- SQL and NoSQL interfaces, now with support for Node.js
- Support for MySQL 5.6, allowing use of the latest InnoDB and NDB engines within one database
- Integrated HA for 99.999% availability
- Auto-Installer that installs, configures, provisions and tunes a production grade cluster in minutes
In addition, you will get a sneak preview of some of the new features planned in MySQL Cluster 7.4 Come and learn how MySQL Cluster can help you differentiate your products and extend their reach into new markets, as well as deliver highly demanding web-based applications, either on premises or in the cloud.
- When using the Memcached API, can I use my existing Memcached connector? Yes. The Memcached API actually uses the regular memcached protocol but then has a custom plugin that acesses the MySQL Cluster data nodes rather than using its local in-memory store.
- If I’m replicating between 2 Clusters in 2 data centres and the WAN fails for a minute – what happens? Because the replication between MySQL Cluster instances is asynchronous – the application isn’t impacted (for example, there will be no extra errors or latency). The changes will be stored in the binary log of the Cluster to which they were sent and then replicated to the other site once the WAN returns.
- Can I scale back down as well as up? It’s an online operation to reduce the number of MySQL Servers (or other application nodes) but that isn’t currently possible for the data nodes. In reality, it’s very rare that applications need to reduce the amount of data they store.
- Are there any MySQL connectors that don’t work with MySQL Cluster? No, any connector that works with MySQL will work just as well with MySQL Cluster.
- Do you have more details on the benchmark results? Yes – take a look at the MySQL Cluster Benchmarks page (http://www.mysql.com/why-mysql/benchmarks/mysql-cluster/" target="_blank).
- I’ve been hearing about MySQL Fabric – does that also allow queries and joins ot span multiple shards? Currently, the only option for cross-shard queries is to use MySQL Cluster or implement them at the application layer.
- Is the data is partioned over diffrent cluster nodes or do all cluster nodes hold the full data set. Each node group stores a subset of the rows from each table. The 2 data nodes within the node group will store the exact same set of rows.
- Where can I find a definition of those different kinds of Foreign Key constraints? The wikipedia definition for Foreign Keys is a good place to start.
- What is the diffrence between ndbcluster and MySQL Cluster ? None – they’re one and the same. When you hear any of “Cluster”, “MySQL Cluster”, “NDB” and “NDB Cluster” the meaning is the same.
- Do I need to have a web server installed for the Auto-Installer to work? No – the MySQL Cluster auto-installer comes with a small web server built-in.
- Are there any dependencies to meet before installing MySQL Cluster on RHEL Liunx? It should work out of the box. My preferred way of working is to use the generic Linux tar ball for MySQL Cluster (get it from the MySQL Cluster download page) – extract it and then run the auto-installer or configure it manually.
- Is there any guide available to migrate mysql nodes to mysql cluster? Probably the closest we have is a white paper on how to get the best out of any PoC for MySQL Cluster (as it highlights what needs to be done differently in order to get the best results)… MySQL Cluster Evaluation Guide (http://www.mysql.com/why-mysql/white-papers/mysql-cluster-evaluation-guide/" target="_blank). Note that MySQL Cluster uses a different version of the mysqld binary and so you’ll need to stop your existing MySQL Server and start up the new one. To migrate a specific table to MySQL Cluster after that is done use “ALTER TABLE my-tab ENGINE=NDB;”.
- Does drupal support MySQL Cluster? I’ve heard of people doing it but I suspect that minor tweaks to teh Drupal code may have been needed.
- How do the NoSQL APIs map to the SQL database schemas? It varies slightly by API – in general, you provide some annotations or meta-data to specify how tables or columns should map to keys/objects/properties. With Memcached you have the option of being schema-less and having all data stored in one, big, generic table.
- Where can I learn more about MySQL Fabric? The MySQL Fabric page (http://www.mysql.com/products/enterprise/fabric.html" target="_blank) is a good starting point; for an end-to-end example, take a look at this tutorial on adding HA and then sharding using MySQL Fabric.
- What is difference between MySQL Fabric and MySQL Cluster? MySQL Fabric provides server farm management on top of ‘regular’ MySQL Servers storing data with the InnoDB storage engine it delivers HA and sharding. MySQL Cluster works below the MySQL Server, storing data in the NDB storage engine (on the data nodes). MySQL Cluster can deliver higher levels of High Availability; better application transparency and cross-shard queries, joins and transactions but it does mean using a different storage engine which of course comes with its own limitations (see the MySQL Cluster Evaluation Guide (http://www.mysql.com/why-mysql/white-papers/mysql-cluster-evaluation-guide/" target="_blank) for details of those).
- So, if I have any full table scans, should I forget about MySQL Cluster> Note necessarily. If every one of your high running operations is a full table scan then MySQL Cluster might not be ideal. However if most operations are simpler but you have some full table scans then that could be fine. The optimisations going into MySQL Cluster 7.4 should particularly benefit table scans.