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BigData-Notes | 大数据入门指南

 by   heibaiying Java Version: Current License: No License

 by   heibaiying Java Version: Current License: No License

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kandi X-RAY | BigData-Notes Summary

BigData-Notes is a Java library typically used in Big Data, Kafka, Spark, Hadoop applications. BigData-Notes has no bugs, it has no vulnerabilities and it has medium support. However BigData-Notes build file is not available. You can download it from GitHub.
大数据入门指南 :star:
Support
Support
Quality
Quality
Security
Security
License
License
Reuse
Reuse

kandi-support Support

  • BigData-Notes has a medium active ecosystem.
  • It has 10343 star(s) with 3059 fork(s). There are 416 watchers for this library.
  • It had no major release in the last 12 months.
  • There are 8 open issues and 23 have been closed. On average issues are closed in 14 days. There are 3 open pull requests and 0 closed requests.
  • It has a neutral sentiment in the developer community.
  • The latest version of BigData-Notes is current.
BigData-Notes Support
Best in #Java
Average in #Java
BigData-Notes Support
Best in #Java
Average in #Java

quality kandi Quality

  • BigData-Notes has 0 bugs and 0 code smells.
BigData-Notes Quality
Best in #Java
Average in #Java
BigData-Notes Quality
Best in #Java
Average in #Java

securitySecurity

  • BigData-Notes has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
  • BigData-Notes code analysis shows 0 unresolved vulnerabilities.
  • There are 0 security hotspots that need review.
BigData-Notes Security
Best in #Java
Average in #Java
BigData-Notes Security
Best in #Java
Average in #Java

license License

  • BigData-Notes does not have a standard license declared.
  • Check the repository for any license declaration and review the terms closely.
  • Without a license, all rights are reserved, and you cannot use the library in your applications.
BigData-Notes License
Best in #Java
Average in #Java
BigData-Notes License
Best in #Java
Average in #Java

buildReuse

  • BigData-Notes releases are not available. You will need to build from source code and install.
  • BigData-Notes has no build file. You will be need to create the build yourself to build the component from source.
  • BigData-Notes saves you 2189 person hours of effort in developing the same functionality from scratch.
  • It has 4793 lines of code, 222 functions and 102 files.
  • It has low code complexity. Code complexity directly impacts maintainability of the code.
BigData-Notes Reuse
Best in #Java
Average in #Java
BigData-Notes Reuse
Best in #Java
Average in #Java
Top functions reviewed by kandi - BETA

kandi has reviewed BigData-Notes and discovered the below as its top functions. This is intended to give you an instant insight into BigData-Notes implemented functionality, and help decide if they suit your requirements.

  • watch for permanent children nodes
  • Main entry point .
  • Performs prePut before put operation .
  • Process Redis command .
  • Step 2 .
  • Create a table .
  • convert InputStream to String
  • Generate data to hdfs .
  • Main execution .
  • Perform flat map aggregation .

BigData-Notes Key Features

大数据入门指南 :star:

Community Discussions

Trending Discussions on Big Data
  • How to group unassociated content
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  • What is the best way to store +3 millions records in Firestore?
  • spark-shell throws java.lang.reflect.InvocationTargetException on running
  • For function over multiple rows (i+1)?
  • Filling up shuffle buffer (this may take a while)
  • Designing Twitter Search - How to sort large datasets?
  • Unnest Query optimisation for singular record
  • handling million of rows for lookup operation using python
  • split function does not return any observations with large dataset
Trending Discussions on Big Data

QUESTION

How to group unassociated content

Asked 2022-Apr-15 at 12:43

I have a hive table that records user behavior

like this

userid behavior timestamp url
1 view 1650022601 url1
1 click 1650022602 url2
1 click 1650022614 url3
1 view 1650022617 url4
1 click 1650022622 url5
1 view 1650022626 url7
2 view 1650022628 url8
2 view 1650022631 url9

About 400GB is added to the table every day.

I want to order by timestamp asc, then one 'view' is in a group between another 'view' like this table, the first 3 lines belong to a same group , then subtract the timestamps, like 1650022614 - 1650022601 as the view time.

How to do this?

i try lag and lead function, or scala like this

        val pairRDD: RDD[(Int, String)] = record.map(x => {
            if (StringUtil.isDateString(x.split("\\s+")(0))) {
                partition = partition + 1
                (partition, x)
            } else {
                (partition, x)
            }
        })

or java like this

        LongAccumulator part = spark.sparkContext().longAccumulator("part");

        JavaPairRDD<Long, Row> pairRDD = spark.sql(sql).coalesce(1).javaRDD().mapToPair((PairFunction<Row, Long, Row>) row -> {
            if (row.getAs("event") == "pageview") {
                part.add(1L);
            }
        return new Tuple2<>(part.value(), row);
        });

but when a dataset is very large, this code just stupid.

save me plz

ANSWER

Answered 2022-Apr-15 at 12:43

If you use dataframe, you can build partition by using window that sum a column whose value is 1 when you change partition and 0 if you don't change partition.

You can transform a RDD to a dataframe with sparkSession.createDataframe() method as explained in this answer

Back to your problem. In you case, you change partition every time column behavior is equal to "view". So we can start with this condition:

import org.apache.spark.sql.functions.col

val df1 = df.withColumn("is_view", (col("behavior") === "view").cast("integer"))

You get the following dataframe:

+------+--------+----------+----+-------+
|userid|behavior|timestamp |url |is_view|
+------+--------+----------+----+-------+
|1     |view    |1650022601|url1|1      |
|1     |click   |1650022602|url2|0      |
|1     |click   |1650022614|url3|0      |
|1     |view    |1650022617|url4|1      |
|1     |click   |1650022622|url5|0      |
|1     |view    |1650022626|url7|1      |
|2     |view    |1650022628|url8|1      |
|2     |view    |1650022631|url9|1      |
+------+--------+----------+----+-------+

Then you use a window ordered by timestamp to sum over the is_view column:

import org.apache.spark.sql.expressions.Window
import org.apache.spark.sql.functions.sum

val df2 = df1.withColumn("partition", sum("is_view").over(Window.partitionBy("userid").orderBy("timestamp")))

Which get you the following dataframe:

+------+--------+----------+----+-------+---------+
|userid|behavior|timestamp |url |is_view|partition|
+------+--------+----------+----+-------+---------+
|1     |view    |1650022601|url1|1      |1        |
|1     |click   |1650022602|url2|0      |1        |
|1     |click   |1650022614|url3|0      |1        |
|1     |view    |1650022617|url4|1      |2        |
|1     |click   |1650022622|url5|0      |2        |
|1     |view    |1650022626|url7|1      |3        |
|2     |view    |1650022628|url8|1      |1        |
|2     |view    |1650022631|url9|1      |2        |
+------+--------+----------+----+-------+---------+

Then, you just have to aggregate per userid and partition:

import org.apache.spark.sql.functions.{max, min}

val result = df2.groupBy("userid", "partition")
  .agg((max("timestamp") - min("timestamp")).as("duration"))

And you get the following results:

+------+---------+--------+
|userid|partition|duration|
+------+---------+--------+
|1     |1        |13      |
|1     |2        |5       |
|1     |3        |0       |
|2     |1        |0       |
|2     |2        |0       |
+------+---------+--------+

The complete scala code:

import org.apache.spark.sql.expressions.Window
import org.apache.spark.sql.functions.{col, max, min, sum}

val result = df
  .withColumn("is_view", (col("behavior") === "view").cast("integer"))
  .withColumn("partition", sum("is_view").over(Window.partitionBy("userid").orderBy("timestamp")))
  .groupBy("userid", "partition")
  .agg((max("timestamp") - min("timestamp")).as("duration"))

Source https://stackoverflow.com/questions/71883786

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install BigData-Notes

You can download it from GitHub.
You can use BigData-Notes like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the BigData-Notes component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

Support

For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .

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