/** Spark SQL Source Code Analysis series Article */Next article spark SQL Catalyst Source Code Analysis physical Plan. This article describes the detailed implementation details of the physical plan Tordd:We all know a SQL, the real run is when you call it the Collect () me
start looking at the end of the last lookup in Builditer, so that each time in the Builditer to find do not have to start from scratch, overall, the search performance is better.Broadcast JOIN implementationIn order to be able to have the same key records into the same partition, we usually do shuffle, then if the builditer is a very small table, then there is no need to make a shuffle, the Builditer broadcast directly to each compute node, Then put
Label:When we have a larger amount of data, we need to split the large table into smaller tables, then queries that only access departmental data can run faster, the basic principle being that the data to be scanned becomes smaller. maintenance tasks (for example, rebuilding an index or backing up a table) can also run faster. We can no longer get the partition by physically placing the table on multiple disk drives to split the table. If you place a
Tags: spark catalyst SQL Spark SQL sharkAfter an article on spark SQL Catalyst Source Code Analysis Physical plan, this article will introduce the specifics of the implementation of the physical plan Tordd:We all know a
Tags: file path log size work partition exec file disk databaseSelect COUNT (1), $PARTITION. WORKDATEPFN (workdate) from Imgfile Group by $PARTITION. WORKDATEPFN (workdate) View the number of partition records select Workdate, $PARTITION. WORKDATEPFN (workdate) from Imgfile
/** Spark SQL Source Code Analysis series Article */Since last year, spark Submit Michael Armbrust shared his catalyst, to now more than 1 years, spark SQL contributor from several people to dozens of people, and the development speed is extremely rapid, the reason, personal
Tag: CAs ORC value try ignores HDFs body overwrite resourceFirst, the basic offline data processing architecture:
Data acquisition Flume:web Log writes to HDFs
Data cleansing of dirty data by Spark, Hive, Mr and other computational frameworks. When you're done cleaning, put it back in HDFs.
Data processing According to needs, conduct business statistics and analysis. Also done through the computational framework
Processing results
Today, while reading Oracle Advanced SQL Programming, there is a section in the chapter on global indexing of Oracle. If you create a unique index on a partitioned table, and the index itself is partitioned, you must also add the partition column to the index list, and certainly not the first column. Then I went to SQL Server and tried it. It's the same with Orac
: Data from 2011-1-1 (including 2011-1-1) to 2011-12-31.3rd Small table: Data from 2012-1-1 (including 2012-1-1) to 2012-12-31.4th Small table: Data after 2013-1-1 (including 2013-1-1).Because the requirements above change the condition of the data partition, we have to modify the partition function, because the function of the partition function is to tell
Tags: good protected register plain should and syntax LAN execution plan/** Spark SQL Source Analysis series Article */ Since last year, Spark's Submit Michael Armbrust shared his catalyst, more than 1 years, spark SQL contributor from a few people to dozens of people, and the development speed is extremely rapid, the
The previous articles introduced the spark SQL Catalyst Sqlparser, and analyzer, originally intended to write optimizer directly, but found forgetting to introduce TreeNode, the core concept of catalyst, This article explains how to better understand how optimizer is generating optimized Logical plan for optimizing analyzed Logical plan, which is explained by the TreeNode infrastructure.First, TreeNode type
: Data from 2011-1-1 (including 2011-1-1) to 2011-12-31.3rd Small table: Data from 2012-1-1 (including 2012-1-1) to 2012-12-31.4th Small table: Data after 2013-1-1 (including 2013-1-1).Because the requirements above change the condition of the data partition, we have to modify the partition function, because the function of the partition function is to tell
WHERE s.id=1Catalyst presses the original query through the predicate, id=1 the selection operation first, filtering the majority of the data, and using the property merge to make the final projection only once to the final reserved Class attribute column.(4) Join optimizationSpark SQL deeply draws on the essence of traditional database query optimization technology, and also makes specific optimization strategy adjustment and innovation in distribut
Label:I. Spark SQL and SCHEMARDD There is no more talking about spark SQL before, we are only concerned about its operation. But the first thing to figure out is what is Schemardd? From the Scala API of spark you can know Org.apache.spark.sql.SchemaRDD and class Schemardd ex
Grouping top data is a common query in T-SQL, such as the Student information management system that takes out the top 3 students in each subject. This query is tedious to write before SQL Server 2005 and requires a temporary table association query to fetch. After SQL Server 2005, the Row_number () function was introduced, and the grouping ordering of the Row_nu
Tags: java se javase roc ring condition ADA tle related diffOne: Parquet use best practices for Spark SQL 1, in the past the entire industry of big data analysis of the technology stack pipeline generally divided into two ways: A) Result Service (can be placed in db), Sparksql/impala, HDFs parquet, HDFs, Mr/hive/spark (equivalent ETL), Data Source , may also be u
Tags: Spark sql DataframeFirst, Spark SQL and DataframeSpark SQL is the cause of the largest and most-watched components except spark core:A) ability to handle all storage media and data in various formats (you can also easily ext
Label:The rationality of database structure and index affects the performance of database to a great extent, but with the increase of database information load, the performance of database is also greatly affected. Maybe our database has high performance at first, but with the rapid growth of data storage--such as order data--the performance of the data is also greatly affected, one obvious result is that the query response will be very slow. What else can you do at this time, in addition to opt
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.