Source : (Informatica, January 2014) Data warehouse optimization using Hadoop, page 8
Optimization of existing data warehouse using Hadoop (HDFS) can be implemented by following below seven steps or fundamental processes which are divided into 2 phases.
1.Offload data & ETL processing to Hadoop : - This step will leverage high CPU consuming ETL processes which were earlier executed on data warehouse causing performance degradation and slow reads and in addition will free space from data warehouse by offloading low-value or infrequently used information onto Hadoop.
2.Batch load raw data to Hadoop : -Data from a wide variety of source systems like existing RDBMS systems, emails, web logs, mobile apps, call center data which means raw transactional, structured, un-structured and semi-structured data will be loaded directly on to Hadoop further reducing impact on the warehouse.
3.Replicate changes and schemas for data : -Entire schemas from RDBMs can be replicated to Hadoop further offloading processing from OLTP. Users can further optimize performanceand reduce latency by choosing the option of change data capture to move only newly updatedinformation.Since Hadoop doesn’t impose schema requirements on data, unstructured information previously unusable by the warehouse can be leveraged in Hadoop.
4.Collect & stream real-time machine data : -Data generated by ICICI Bank’s mobile as well as web applications and web site including web log files, click streams can be collected in
Hadoop \cite{white2012hadoop} is an open-source framework for distributed storage and data-intensive processing, first developed by Yahoo!. It has two core projects: Hadoop Distributed File System (HDFS) and MapReduce programming model \cite{dean2008mapreduce}. HDFS is a distributed file system that splits and stores data on nodes throughout a cluster, with a number of replicas. It provides an extremely reliable, fault-tolerant, consistent, efficient and cost-effective way to store a large amount of data. The MapReduce model consists of two key functions: Mapper and Reducer. The Mapper processes input data splits in parallel through different map tasks and sends sorted, shuffled outputs to the Reducers that in turn groups and processes them using a reduce task for each group.
MapReduce Parallel programming model if we ever get a chance. In Hadoop, there are two nodes in the cluster when using the algorithm, Master node and Slave node. Master node runs Namenode, Datanode, Jobtracker and Task tracker processes. Slave node runs the Datanode and Task tracker processes. Namenode manages partitioning of input dataset into blocks and on which node it has to store. Lastly, there are two core components of Hadoop: HDFS layer and MapReduce layer. The MapReduce layer read from and write into HDFS storage and processes data in parallel.
The Hadoop employs MapReduce paradigm of computing which targets batch-job processing. It does not directly support the real time query execution i.e OLTP. Hadoop can be integrated with Apache Hive that supports HiveQL query language which supports query firing, but still not provide OLTP tasks (such as updates and deletion at row level) and has late response time (in minutes) due to absence of pipeline
Hadoop1 provides a distributed filesystem and a framework for the analysis and transformation of very large data sets using the MapReduce [DG04] paradigm. While the interface to HDFS is patterned after the Unix filesystem, faithfulness to standards was sacrificed in favor of improved performance for the applications at hand.
Hadoop is a free, Java-based programming framework that supports the processing of large data sets in a Parallel and distributed computing environment. It makes Use of the commodity hardware Hadoop is Highly Scalable and Fault Tolerant. Hadoop runs in cluster and eliminates the use of a Super computer. Hadoop is the widely used big data processing engine with a simple master slave setup. Big Data in most companies are processed by Hadoop by submitting the jobs to Master. The Master distributes the job to its cluster and process map and reduce tasks sequencially.But nowdays the growing data need and the and competition between Service Providers leads to the increased submission of jobs to the Master. This Concurrent job submission on Hadoop forces us to do Scheduling on Hadoop Cluster so that the response time will be acceptable for each job.
A data warehousing is defined as a collection of data designed to support management decision making. Data warehouses contains a wide variety of data that present a coherent picture of the business conditions at a single point in time. Development of a data warehouse includes development of the systems that extract data from operating systems plus the installation of the warehouse database system that provides managers flexible access to the data. The term data warehousing generally refer to the combination of many different databases across an entire enterprise. (webopidia)
Research topic was derived from the understanding of query processing in MySQL and Hadoop, the database performance issues, performance tuning and the importance of database performance. Thus, it was decided to develop a comparative analysis to observe the effectiveness of the performance of MySQL (non cluster) and Hadoop in structured and unstructured dataset (Rosalia, 2015). Furthermore, the analysis included a comparison between those two platforms in two variance of data size.
In an attempt to manage their data correctly, organizations are realizing the importance of Hadoop for the expansion and growth of business. According to a study done by Gartner, an organization loses approximately 8.2 Million USD annually through poor data quality. This happens when 99 percent of the organizations have their data strategies in place. The reason behind this is simple – the organizations are unable to trace the bad data that exists within their data. This is one problem which can be easily solved by adopting Hadoop testing methods which allows you to validate all of your data at increased testing speeds and boosts your data coverage resulting in better data quality.
Cost reduction: Big data technologies such as Hadoop and cloud based analytics bring significant cost advantages when it comes to storing large amounts of data – plus they can identify and implement more efficient ways of doing business.
Hadoop is one of the open source frameworks, is used as extension to big data analytics framework which are used by a large group of vendors. This type of framework makes work easy for the companies how they?re going to store and can use the data within the digital products as well as physical products (James, M. et al. 2011). We can analyze data using Hadoop, which is emerging as solution to
The paper “A Comparison to Approaches to Large-Scale Data Analysis” by Pavlo, compares and analyze the MapReduce framework with the parallel DBMSs, for large scale data analysis. It benchmarks the open source Hadoop, build over MapReduce, with two parallel SQL databases, Vertica and a second system form a major relational vendor (DBMS-X), to conclude that parallel databases clearly outperform Hadoop on the same hardware over 100 nodes. Averaged across 5 tasks on 100 nodes, Vertica was 2.3 faster than DBMS-X which in turn was 3.2 times faster than MapReduce. In general, the parallel SQL DBMSs were significantly faster and required less code to implement each task, but took longer to tune and load the data. Finally, the paper talk about
Many database vendors offer commercial Hadoop distribution with their appliance or hardware. This offer can easily be integrated with the current data warehouse infrastructure. However, I work with customers who adopted commodity server to control costs and work within their budgets. Commodity servers are simply a bunch of disks with single power supplies to store data. Adopting commodity servers will require resources to be trained, to manage and gain knowledge of how Hadoop works on commodity. Adopting commodity can be an alternative but may not be suited for your
Abstract - Hadoop Distributed File System, a Java based file system provides reliable and scalable storage for data. It is the key component to understand how a Hadoop cluster can be scaled over hundreds or thousands of nodes. The large amounts of data in Hadoop cluster is broken down to smaller blocks and distributed across small inexpensive servers using HDFS. Now, MapReduce functions are executed on these smaller blocks of data thus providing the scalability needed for big data processing. In this paper I will discuss in detail on Hadoop, the architecture of HDFS, how it functions and the advantages.
Data warehouse are multiple databases that work together. In other words, data warehouse integrates data from other databases. This will provide a better understanding to the data. Its primary goal is not to just store data, but to enhance the business, in this case, higher education institute, a means to make decisions that can influence their success. This is accomplished, by the data warehouse providing architecture and tools which organizes and understands the
Data has always been analyzed within companies and used to help benefit the future of businesses. However, the evolution of how the data stored, combined, analyzed and used to predict the pattern and tendencies of consumers has evolved as technology has seen numerous advancements throughout the past century. In the 1900s databases began as “computer hard disks” and in 1965, after many other discoveries including voice recognition, “the US Government plans the world’s first data center to store 742 million tax returns and 175 million sets of fingerprints on magnetic tape.” The evolution of data and how it evolved into forming large databases continues in 1991 when the internet began to pop up and “digital storage became more cost effective than paper. And with the constant increase of the data supplied digitally, Hadoop was created in 2005 and from that point forward there was “14.7 Exabytes of new information are produced this year" and this number is rapidly increasing with a lot of mobile devices the people in our society have today (Marr). The evolution of the internet and then the expansion of the number of mobile devices society has access to today led data to evolve and companies now need large central Database management systems in order to run an efficient and a successful business.