Post Syndicated from John Hwang original https://aws.amazon.com/blogs/big-data/migrating-your-netezza-data-warehouse-to-amazon-redshift/
With IBM announcing Netezza reaching end-of-life, you’re faced with the prospect of having to migrate your data and workloads off your analytics appliance. For some, this presents an opportunity to transition to the cloud.
Enter Amazon Redshift.
Amazon Redshift is a cloud-native data warehouse platform built to handle workloads at scale, and it shares key similarities with Netezza that make it an excellent candidate to replace your on-premises appliance. You can migrate your data and applications to Amazon Redshift in less time and with fewer changes than migrating to other analytics platforms. For developers, this means less time spent retraining on the new database. For stakeholders, it means a lower cost of, and time to, migration. For more information, see How to migrate a large data warehouse from IBM Netezza to Amazon Redshift with no downtime.
This post discusses important similarities and differences between Netezza and Amazon Redshift, and how they could impact your migration timeline.
Three significant similarities between Netezza and Amazon Redshift are their compatibility with Postgres, their massively parallel processing (MPP) architecture, and the Amazon Redshift feature Advanced Query Accelerator (AQUA) compared to Netezza’s use of FPGAs.
Both Netezza and Amazon Redshift share some compatibility with Postgres, an open-source database. This means that Netezza SQL and Amazon Redshift SQL have a similar syntax. In particular, both support many features of PL/pgSQL, Postgres’s procedural language. Your Netezza stored procedures can translate to Amazon Redshift with little-to-no rewriting of code.
You can also use the AWS Schema Conversion Tool, which can automatically migrate a large percentage of Netezza storage procedures to Amazon Redshift syntax with zero user effort. And because both databases are built for analytics and not transactional workloads, there are similar characteristics between the two databases. For example, both Netezza and Amazon Redshift don’t enforce primary keys to improve performance, though you can still define primary keys on your tables to help the optimizer create better query plans.
Both Netezza and Amazon Redshift are MPP databases. This means that a query is sent to a leader node, which then compiles a set of commands that it sends to multiple compute nodes. Each worker node performs its task in parallel and returns the results to the leader node, where the results are aggregated and returned to the user. This means that you can apply similar architectural strategies from Netezza, such as zone maps and distribution styles, to Amazon Redshift. For more information, see Amazon Redshift Engineering’s Advanced Table Design Playbook: Preamble, Prerequisites, and Prioritization.
Amazon Redshift AQUA and Netezza’s FPGA
AWS recently announced the new Amazon Redshift feature AQUA, which is in preview as of this writing. AQUA uses AWS-designed processors to bring certain compute tasks closer to the storage layer. Compression, encryption, filtering, aggregation—and other tasks—can now happen in this intermediary layer in between the storage and compute, which leaves the CPU free to handle more complex tasks. When it’s released, AQUA will accelerate queries up to 10 times faster.
Netezza uses FPGAs to perform simple compute tasks before data reaches the CPU. Applications designed to employ these FPGA features on Netezza (for example, queries that rely heavily on certain aggregate functions and data filtering) translate well to Amazon Redshift clusters using AQUA.
For all the similarities that Amazon Redshift and Netezza share, they also have differences. There are three important differences that could have significant impact on your data and application architecture when migrating from Netezza to Amazon Redshift: column store vs. row store, concurrency scaling, and data lake integration.
Column store vs. row store
Netezza stores each row of data onto disk in data blocks, whereas Amazon Redshift stores each column of data. For many analytics workloads, a column store can have dramatic performance benefits over a row store. Typically, an analytics database has tables with many columns, but only a small handful of those columns are used in any one query. For example, assume that you have a table in a row store database with 100 columns and 100 million rows. If you want to sum the entire value of one column in this table, your query has to suffer the I/O penalty of scanning the entire table to retrieve the data in this single column. In a columnar database with the same table, the query only faces I/O for the single column. In addition to enjoying the improved performance for this type of workload in Amazon Redshift, this gives you options for designing wide tables without having to weigh the increase in I/O for typical analytics workloads the way you do in Netezza.
Although both Netezza and Amazon Redshift offer queue priority and short query acceleration to help reduce concurrency issues, Amazon Redshift also uses the benefits of the cloud to offer additional options to handle concurrency.
One option is to take unrelated workloads from a single Netezza appliance and migrate them to separate Amazon clusters, each with an instance type and number of nodes sized accordingly for the workload it has to support. Netezza’s more traditional license and support pricing model, combined with its limited options for appliance sizes, can make this type of architecture untenable for your organization’s budget.
Additionally, Amazon Redshift offers Concurrency Scaling to scale out (and scale back in) additional compute capacity automatically and on the fly. If you want to add or remove nodes in the cluster, or experiment with other nodes types, you can do so in just a few minutes using elastic resize (to change the number of nodes) and classic resize (to change instance types).
This type of scaling and resizing isn’t feasible on Netezza because the on-premises appliance has a fixed number of blades. Concurrency scaling in Amazon Redshift can support virtually unlimited concurrent users and concurrent queries, and its ability to automatically add and remove additional capacity means you only pay for the time the concurrency scaling clusters are in use.
Data lake integration
Netezza offers the ability to create an external table from a data file either on the Netezza host or a remote host. However, querying those tables means migrating the entire dataset internally before running the query. With Amazon Redshift Spectrum, rather than using external tables as a convenient way to migrate entire datasets to and from the database, you can run analytical queries against data in your data lake the same way you do an internal table. As the volume of your data in the lake grows, partitioning can help keep the amount of data scanned for each query (and therefore performance) consistent. You can even join the data from your external tables in Amazon Simple Storage Service (Amazon S3) to your internal tables in Amazon Redshift.
Not only does this mean true integration of your data warehouse and data lake, which can lower your warehouse’s more expensive storage requirements, but because the Amazon Redshift Spectrum layer uses its own dedicated infrastructure outside of your cluster, you can offload many compute-intensive tasks from your cluster and push them down to the Redshift Spectrum layer. For more information, see Amazon Redshift Spectrum overview.
Amazon Redshift can accelerate migration from Netezza and potentially lower the time and cost of moving your analytics workloads into the cloud. The similarity between the two systems eases the pain of migration, but Amazon Redshift has important differences that can offer additional benefits around performance and cost. The expertise of AWS and its partner network can help with your migration strategy and offer guidance to avoid potential roadblocks and pitfalls.
About the Author
John Hwang is a senior solutions architect at AWS.
Brian McDermott is a senior sales manager at AWS.