|By Srinivasan Sundara Rajan||
|March 14, 2013 11:15 AM EDT||
Data Warehouse as a Service
Recently Amazon announced the availability of Redshift Data warehouse as a Service as a beta offering. Amazon Redshift is a fast, fully managed, petabyte-scale data warehouse service that makes it simple and cost-effective to efficiently analyze all your data using your existing business intelligence tools. It's optimized for datasets ranging from a few hundred gigabytes to a petabyte or more and costs less than $1,000 per terabyte per year, a tenth the cost of most traditional data warehousing solutions.
Architecture Behind Redshift
Any data warehouse service meant to serve data of petabyte scale should have a robust architecture as its backbone. The following are the salient features of Redshift service.
- Shared Nothing Architecture: As indicated in one of my earlier articles, Cloud Database Scale Out Using Shared Nothing Architecture, the shared nothing architectural pattern is the most desired for databases of this scale and the same concept is adhered to in Redshift. The core component of Redshift is a cluster and each cluster consists of multiple compute nodes, each node has its dedicated storage following the shared nothing principle.
- Massively Parallel Processing (MPP): Hand in hand with the shared nothing pattern MPP provides horizontal scale out capabilities for large data warehouses rather than scaling up the individual servers. Massively parallel processing (MPP) enables fast execution of the most complex queries operating on large amounts of data. Multiple compute nodes handle all query processing leading up to the final result aggregation, with each core of each node executing the same compiled query segments on portions of the entire data. With the concept of NodeSlices Redshift has taken the MPP to the next level to the cores of a compute node. A compute node is partitioned into slices; one slice for each core of the node's multi-core processor. Each slice is allocated a portion of the node's memory and disk space, where it processes a portion of the workload assigned to the node.
Refer to the following diagram from AWS Documentation, about Data warehouse system architecture
- Columnar Data Storage: Storing database table information in a columnar fashion reduces the number of disk I/O requests and reduces the amount of data you need to load from disk. Columnar storage for database tables drastically reduces the overall disk I/O requirements and is an important factor in optimizing analytic query performance.
- Leader Node: The leader node manages most communications with client programs and all communication with compute nodes. It parses and develops execution plans to carry out database operations, in particular, the series of steps necessary to obtain results for complex queries. Based on the execution plan, the leader node distributes compiled code to the compute nodes and assigns a portion of the data to each compute node.
- High Speed Network Connect: The clusters are connected internally by a 10 Gigabit Ethernet network, providing very fast communication between the leader node and the compute clusters.
Best Practices in Application Design on Redshift
The enablement of Big Data analytics through Redshift has created lot of excitement among the community. The usage of these kinds of alternate approaches to traditional data warehousing will be best in conjunction with the best practices for utilizing the features. The following are some of the best practices that can be considered for the design of applications on Redshift.
1. Collocated Tables: It is good practice to try to avoid sending data between the nodes to satisfy JOIN queries. Colocation between two joined tables occurs when the matching rows of the two tables are stored in the same compute nodes, so that the data need not be sent between nodes.
When you add data to a table, Amazon Redshift distributes the rows in the table to the cluster slices using one of two methods:
- Even distribution
- Key distribution
Even distribution is the default distribution method. With even distribution, the leader node spreads data rows across the slices in a round-robin fashion, regardless of the values that exist in any particular column. This approach is a good choice when you don't have a clear option for a distribution key.
If you specify a distribution key when you create a table, the leader node distributes the data rows to the slices based on the values in the distribution key column. Matching values from the distribution key column are stored together.
Colocation is best achieved by choosing the appropriate distribution keys than using the even distribution.
If you frequently join a table, specify the join column as the distribution key. If a table joins with multiple other tables, distribute on the foreign key of the largest dimension that the table joins with. If the dimension tables are filtered as part of the joins, compare the size of the data after filtering when you choose the largest dimension. This ensures that the rows involved with your largest joins will generally be distributed to the same physical nodes. Because local joins avoid data movement, they will perform better than network joins.
2. De-Normalization: In the traditional RDBMS, database storage is optimized by applying the normalization principles such that a particular attribute (column) is associated with one and only entity (Table). However in shared nothing scalable databases like Redshift this technique will not yield the desired results, rather keeping the redundancy of certain columns in the form of de-normalization is very important.
For example, the following query is one of the examples of a high performance query in the Redshift documentation.
SELECT * FROM tab1, tab2
WHERE tab1.key = tab2.key
AND tab1.timestamp > ‘1/1/2013'
AND tab2.timestamp > ‘1/1/2013';
Even if a predicate is already being applied on a table in a join query but transitively applies to another table in the query, it's useful to re-specify the redundant predicate if that other table is also sorted on the column in the predicate. That way, when scanning the other table, Redshift can efficiently skip blocks from that table as well.
By carefully applying de-normalization to bring the required redundancy, Amazon Redshift can perform at its best.
3. Native Parallelism: One of the biggest advantages of a shared nothing MPP architecture is about parallelism. Parallelism is achieved in multiple ways.
- Inter Node Parallelism: It refers the ability of the database system to break up a query into multiple parts across multiple instances across the cluster.
- Intra Node Parallelism: Intra node parallelism refers to the ability to break up query into multiple parts within a single compute node.
Typically in MPP architectures, both Inter Node Parallelism and Intra Node Parallelism will be combined and used at the same time to provide dramatic performance gains.
Amazon Redshift provides lot of operations to utilize both Intra Node and Inter Node parallelism.
When you use a COPY command to load data from Amazon S3, first split your data into multiple files instead of loading all the data from a single large file.
The COPY command then loads the data in parallel from multiple files, dividing the workload among the nodes in your cluster. Split your data into files so that the number of files is a multiple of the number of slices in your cluster. That way Amazon Redshift can divide the data evenly among the slices. Name each file with a common prefix. For example, each XL compute node has two slices, and each 8XL compute node has 16 slices. If you have a cluster with two XL nodes, you might split your data into four files named customer_1, customer_2, customer_3, and customer_4. Amazon Redshift does not take file size into account when dividing the workload, so make sure the files are roughly the same size.
Pre-Processing Data: Over the years RDBMS engines take pride of Location Independence. The Codd's 12 rules of the RDBMS states the following:
Rule 8: Physical data independence:
Changes to the physical level (how the data is stored, whether in arrays or linked lists, etc.) must not require a change to an application based on the structure.
However, in the columnar database services like Redshift the physical ordering of data does make major impact to the performance.
Sorting data is a mechanism for optimizing query performance.
When you create a table, you can define one or more of its columns as the sort key. When data is loaded into the table, the values in the sort key column (or columns) are stored on disk in sorted order. Information about sort key columns is passed to the query planner, and the planner uses this information to construct plans that exploit the way that the data is sorted. For example, a merge join, which is often faster than a hash join, is feasible when the data is distributed and presorted on the joining columns.
The VACUUM command also makes sure that new data in tables is fully sorted on disk. Vacuum as often as you need to in order to maintain a consistent query performance.
Platform as a Service (PaaS) is one of the greatest benefits to the IT community due to the Cloud Delivery Model, and from the beginning of pure play programming models like Windows Azure and Elastic Beanstalk it has moved to high-end services like data warehouse Platform as a Service. As the industry analysts see good adoption of the above service due to the huge cost advantages when compared to the traditional data warehouse platform, the best practices mentioned above will help to achieve the desired level of performance. Detailed documentation is also available on the vendor site in the form of developer and administrator guides.
“The year of the cloud – we have no idea when it's really happening but we think it's happening now. For those technology providers like Zentera that are helping enterprises move to the cloud - it's been fun to watch," noted Mike Loftus, VP Product Management and Marketing at Zentera Systems, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 06:00 PM EST Reads: 427
As enterprises engage with Big Data technologies to develop applications needed to meet operational demands, new computation fabrics are continually being introduced. To leverage these new innovations, organizations are sacrificing market opportunities to gain expertise in learning new systems. In his session at Big Data Expo, Supreet Oberoi, Vice President of Field Engineering at Concurrent, Inc., discussed how to leverage existing infrastructure and investments and future-proof them against e...
Dec. 17, 2014 06:00 PM EST Reads: 1,956
"For over 25 years we have been working with a lot of enterprise customers and we have seen how companies create applications. And now that we have moved to cloud computing, mobile, social and the Internet of Things, we see that the market needs a new way of creating applications," stated Jesse Shiah, CEO, President and Co-Founder of AgilePoint Inc., in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 06:00 PM EST Reads: 1,924
"People are a lot more knowledgeable about APIs now. There are two types of people who work with APIs - IT people who want to use APIs for something internal and the product managers who want to do something outside APIs for people to connect to them," explained Roberto Medrano, Executive Vice President at SOA Software, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 06:00 PM EST Reads: 1,757
“DevOps is really about the business. The business is under pressure today, competitively in the marketplace to respond to the expectations of the customer. The business is driving IT and the problem is that IT isn't responding fast enough," explained Mark Levy, Senior Product Marketing Manager at Serena Software, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 06:00 PM EST Reads: 277
Mobile commerce traffic is surpassing desktop, yet less than 20% of sales in the U.S. are mobile commerce sales. In his session at 15th Cloud Expo, Dan Franklin, Segment Manager, Commerce, at Verizon Digital Media Services, defined mobile devices and discussed how next generation means simplification. It means taking your digital content and turning it into instantly gratifying experiences.
Dec. 17, 2014 05:45 PM EST Reads: 797
The Internet of Things is a misnomer. That implies that everything is on the Internet, and that simply should not be - especially for things that are blurring the line between medical devices that stimulate like a pacemaker and quantified self-sensors like a pedometer or pulse tracker. The mesh of things that we manage must be segmented into zones of trust for sensing data, transmitting data, receiving command and control administrative changes, and peer-to-peer mesh messaging. In his session a...
Dec. 17, 2014 05:15 PM EST Reads: 1,856
"Ulunsoft is a start-up that focuses on how enterprises build cloud-based IT infrastructure for business," explained Haibo Zhu, President of Ulunsoft Corp, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 05:00 PM EST Reads: 1,462
"Desktop as a Service is emerging as a very big trend. One of the big influencers of this – for Esri – is that we have a large user base that uses virtualization and they are looking at Desktop as a Service right now," explained John Meza, Product Engineer at Esri, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 04:30 PM EST Reads: 2,107
SYS-CON Events announced today that Gridstore™, the leader in hyper-converged infrastructure purpose-built to optimize Microsoft workloads, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Gridstore™ is the leader in hyper-converged infrastructure purpose-built for Microsoft workloads and designed to accelerate applications in virtualized environments. Gridstore’s hyper-converged infrastructure is the ...
Dec. 17, 2014 04:30 PM EST Reads: 1,773
"At our booth we are showing how to provide trust in the Internet of Things. Trust is where everything starts to become secure and trustworthy. Now with the scaling of the Internet of Things it becomes an interesting question – I've heard numbers from 200 billion devices next year up to a trillion in the next 10 to 15 years," explained Johannes Lintzen, Vice President of Sales at Utimaco, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in San...
Dec. 17, 2014 04:15 PM EST Reads: 1,920
"Application monitoring and intelligence can smooth the path in a DevOps environment. In a DevOps environment you see constant change. If you are trying to monitor things in a constantly changing environment, you're going to spend a lot of your job fixing your monitoring," explained Todd Rader, Solutions Architect at AppDynamics, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 04:00 PM EST Reads: 2,282
Today’s enterprise is being driven by disruptive competitive and human capital requirements to provide enterprise application access through not only desktops, but also mobile devices. To retrofit existing programs across all these devices using traditional programming methods is very costly and time consuming – often prohibitively so. In his session at @ThingsExpo, Jesse Shiah, CEO, President, and Co-Founder of AgilePoint Inc., discussed how you can create applications that run on all mobile ...
Dec. 17, 2014 11:45 AM EST Reads: 2,040
"SOASTA built the concept of cloud testing in 2008. It's grown from rather meager beginnings to where now we are provisioning hundreds of thousands of servers on a daily basis on behalf of customers around the world to test their applications," explained Tom Lounibos, CEO of SOASTA, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 11:30 AM EST Reads: 1,767
“We are a managed services company. We have taken the key aspects of the cloud and the purposed data center and merged the two together and launched the Purposed Cloud about 18–24 months ago," explained Chetan Patwardhan, CEO of Stratogent, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 11:00 AM EST Reads: 1,630
We certainly live in interesting technological times. And no more interesting than the current competing IoT standards for connectivity. Various standards bodies, approaches, and ecosystems are vying for mindshare and positioning for a competitive edge. It is clear that when the dust settles, we will have new protocols, evolved protocols, that will change the way we interact with devices and infrastructure. We will also have evolved web protocols, like HTTP/2, that will be changing the very core...
Dec. 16, 2014 11:45 PM EST Reads: 1,911
"Verizon Digital Media Services is responsible for the broadcast, video and content delivery network that accelerates, scales and helps our customers reach end users with all kinds of video and web content," stated James Segil, CMO of Verizon Digital Media Services, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 16, 2014 10:00 PM EST Reads: 1,734
SYS-CON Events announced today that Creative Business Solutions will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Creative Business Solutions is the top stocking authorized HP Renew Distributor in the U.S. Based out of Long Island, NY, Creative Business Solutions offers a one-stop shop for a diverse range of products including Proliant, Blade and Industry Standard Servers, Networking, Server Options and...
Dec. 16, 2014 09:30 PM EST Reads: 1,588
You use an agile process; your goal is to make your organization more agile. But what about your data infrastructure? The truth is, today's databases are anything but agile - they are effectively static repositories that are cumbersome to work with, difficult to change, and cannot keep pace with application demands. Performance suffers as a result, and it takes far longer than it should to deliver new features and capabilities needed to make your organization competitive. As your application an...
Dec. 16, 2014 08:00 PM EST Reads: 1,892
“We are strong believers in the DevOps movement and our staff has been doing DevOps for large enterprise environments for a number of years. The solution that we build is intended to allow DevOps teams to do security at the speed of DevOps," explained Justin Lundy, Founder & CTO of Evident.io, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 16, 2014 06:00 PM EST Reads: 1,446