Parallel Database design, query processing, and case study In this post, we are going to analyze the concepts of Parallel Database design, query processing, and case study. Parallel database design Hardware Architecture Data partitioning Query processing Hardware Architecture Shared Memory Shared Disk> Shared Nothing Data Partitioning Partitioning a relation involves distributing its tuples over several disks Three Kinds – Range Partitioning Round-robin Partitioning Hashing Partitioning Range Partitioning is good for Ideal for point and range queries on the partitioning attribute Hash partitioning Ideal for point queries based on the partitioning attribute Ideal for sequential sca...
Apache Hadoop | Running MapReduce Jobs After setting up your environment and running the HDFS and YARN daemons, we can start working on running MapReduce jobs on our local machine. We need to compile our code, produce a JAR file, move our inputs, and run a MapReduce job on Hadoop. Step 1 - Configure extra environment variables As a preface, it is best to setup some extra environment variables to make running jobs from the CLI quicker and easier. You can name these environment variables anything you want, but we will name them HADOOP_CP and HDFS_LOC to not potentially conlict with other environment variables. Open the Start Menu and type in 'environment' and press enter. A new window with System Properties should open up. Click the Environment Variables button near the bottom right. HADOOP_CP environment variable This is used to compile your Java files. The backticks (eg. `some command here`) do not work on Win...
jQuery API - Part 1 jQuery has many functions, both synchronous and asynchronous which reduce the task of the programmer and are Efficient Reliable Fast Scalable For getting the immediate ancestor of an element use $("#element_id").parent(); jQuery implements method chaining which means that all jQuery functions that work on a selector process the element and returns the new jQuery variable i.e., $("#element_id") The benefit of jQuery JavaScript library having method chaining is that if you want to perform 10 functions on a single element, it becomes tedious to create 10 new variables assign value to each of them and storing the results in a different variable. So, to get the grandfather of an element, use $("#element_id").parent().parent(); To get / set attributes of an HTML element, use attr() method. Example: If you want the value of the co...
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