Hypertable is an open source project based on published best practices and our own experience in solving large-scale data-intensive tasks. Our goal is nothing. Modeled after Bigtable. ➢ Implemented in C++. ➢ Project Started in March ➢ Runs on top of HDFS. ➢ Thrift Interface for all popular languages. ○ Java. hypertable> create namespace “Tutorial”;. hypertable> use Tutorial;. create table. hypertable> CREATE TABLE QueryLogByUserID (Query.
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To restrict the MapReduce to a specific row interval of the input table, a row range can be specified with the hypertable. In this tutorial we hypegtable be loading data into, and querying data from, hypertaboe separate tables. Now ttutorial load the data file query-log. A relational database assumes that each column defined in the table schema will have a value for each row that is present in the table. This function can also be used through the Thrift interface.
This feature provides a way for users to introduce sparse column data that can be easily selected with Hypertable Query Language HQL or any of the other query interfaces. Heres a small sample from the dataset:. Hypertable supports two types of indices: All of the example queries show were run against a table with the following schema and loaded with products.
The result set was fairly large cellsso let’s now try selecting just the queries that were issued by the user with ID during the hour of 5am. See the HQL Documentation: Hypertable contains support for secondary indices. In the schema, the rowkey is a URL and the title, description and topic are column families. This file includes an initial header line indicating the format of each line in the file by listing tab delimited column names. Under high concurrency, step 2 can become a bottleneck.
To insert values, create a mutator and write the unique cell to the database. The table is created with the following HQL:. Over time, Hypertable will break these tables into ranges and distribute them to what are known as RangeServer processes. Otherwise the cell already existed with a different value. The following example illustrates how a row interval is passed into a Hadoop Streaming MapReduce program.
The remainder of this section assumes a CDH4 installation, change command lines accordingly for your distribution.
This is why we imported the data into a second table QueryLogByTimestamp. Tables in Hypertable can be thought of as massive tables of data, sorted by a single primary key, the row key. Hypertable ships with a jar file, hypertable. Then create a scanner, fetch the cell and verify that it was written correctly. Each unique word in the article turns into a qualified column and the value is the number of times the word appears in the article.
If we hadn’t supplied that option, the system would have auto-assigned a timestamp. Hypertable will hypertwble that there are new servers available with plenty of spare capacity and will automatically migrate ranges from the overloaded machines onto the new ones.
In this example, we’ll be running the WikipediaWordCount tuhorial which is included in the hypertable-examples. The mapper script tokenize-article. CommitInterval, which acts as a lower bound default is 50ms. Counter columns are accessed using the same methods as other columns.
User Guide | Hypertable – Big Data. Big Performance
In this section, we walk you through an example MapReduce program, WikipediaWordCount, that tokenizes articles in a table called wikipedia that has been loaded with a Wikipedia dump. This tutorial shows you how to import a search engine query log into Hypertable, storing the data into tables with different primary keys, and how to issue queries against the tables.
Like the example in the previous section, the programs operate on a table called wikipedia that has been loaded with a Wikipedia dump. To run a MapReduce job over a subset of columns from the input table, specify a comma separated list of columns in the hypertable.
This page provides a brief overview of Hypertable, comparing it with a relational database, highlighting some of its unique features, and illustrating how it scales.
Since this process is a bit cumbersome we introduced the HyperAppHelper library. Unique cells are useful i.
This section illustrates how Hypertable scales. This document describes how to create a table with secondary indices and how to forulate queries that leverage these indices. The following is a list of some of the main tutoriial. First, open the root namespace. Keep in mind that the internal cell timestamp is different than the one embedded in the row key.