logo
down
shadow

Does every record in a Flink EventTime application need a timestamp?


Does every record in a Flink EventTime application need a timestamp?

Content Index :

I hope this helps . Generally speaking, the best approach is to have proper event-time timestamps on every event, and to use event-time everywhere. This has the advantage of being able to use the exact same code for both live data and historic data -- which is very valuable when the need arises to re-process historic data in order to fix bugs or upgrade your pipeline. With this in mind, it's typically possible to do backfill by simply running a second copy of the application -- one that's processing historic data rather than live data.
As for using a mix of historic and live data in the same application, and whether you need to have timestamps and watermarks for the historic events -- it depends on the details. For example, if you are going to connect the two streams, the watermarks (or lack of watermarks) on the historic stream will hold back the watermarks on the connected stream. This will matter if you try to use event-time timers (or windows, which depend on timers) on the connected stream.

Comments
No Comments Right Now !

Boards Message :
You Must Login Or Sign Up to Add Your Comments .

Share : facebook icon twitter icon

Unix: Extract timestamp from first record in xml file and it checks if not it will replace first record timestamp


Tag : xml , By : Tom D
Date : March 29 2020, 07:55 AM
it helps some times I have test.xml , i used AWK
awk -F '</?date>' '
                 #{printf("%s \"%s\"\n", substr($0, 1, 2), $2)}
                 /^<emp>/ { ed = $2
                        cd = substr($2, 7, 2) substr($2, 1, 2) substr($2, 4, 2) substr($2, 10)
                        print next }
                /^<Join>/ {
                        if(cd > (substr($2, 7, 2) substr($2, 1, 2) substr($2, 4, 2) substr($2, 10)))
                        $0 = $1 "<date>" ed "</date>" $3 } 1' test.xml

EventTime windowing from Kafka stream causing "Timestamp monotony violated" error


Tag : development , By : Frank Bradley
Date : March 29 2020, 07:55 AM
To fix the issue you can do I believe that unless you can guarantee forward progress in timestamps across all partitions, because you are extracting timestamps and watermarks outside of your source, you will get this error.
What you can potentially do is use your SeriesMap class as a Kafka DeserializationSchema and then do the assignTimestampsAndWatermarks against your Kafka source. Kafka will then have no issues with your timestamps moving forward separately within each partition, and the global watermark it emits will be the minimum of the watermark encountered across all partitions.

Tag : java , By : Vijayant Singh
Date : March 29 2020, 07:55 AM
Does that help Flink allows the use of processing time windows with event time streams, because there are legitimate use cases for that. But if you do want event time windowing, you need to ask for it. In this case you should be using TumblingEventTimeWindows.

Timestamp & Watermark assigning for two input streams, later connected for dynamic alerting using 'EventTime'


Tag : java , By : UpperLuck
Date : March 29 2020, 07:55 AM
I hope this helps . This exercise in the Flink training covers exactly this case: https://training.ververica.com/exercises/taxiQuery.html. See the hints and the solution for details, but the approach taken there is to use this timestamp extractor / watermark generator on the stream with the rules:
// Once the two streams are connected, the Watermark of the KeyedBroadcastProcessFunction operator
// will be the minimum of the Watermarks of the two connected streams. Our query stream has a default
// Watermark at Long.MIN_VALUE, and this will hold back the event time clock of the
// KeyedBroadcastProcessFunction, unless we do something about it.
public static class QueryStreamAssigner implements AssignerWithPeriodicWatermarks<String> {
    @Nullable
    @Override
    public Watermark getCurrentWatermark() {
        return Watermark.MAX_WATERMARK;
    }

    @Override
    public long extractTimestamp(String element, long previousElementTimestamp) {
        return 0;
    }
}

Tag : development , By : Jay Crockett
Date : March 29 2020, 07:55 AM
I wish did fix the issue. One way to solve this problem is to generate watermarks after mixing together events from all of the partitions, so that the slow/idle partition doesn't hold back the overall watermark:
stream
  .rebalance()
  .assignTimestampsAndWatermarks(...)
  .keyBy(...)
  .timeWindow(...)
Related Posts Related QUESTIONS :
  • Why this type is not an Interface?
  • SugarCRM Rest API set_relationship between Contacts and Documents
  • Jira dashboard organization
  • Web worker importScripts fails to place script variables in global scope
  • Always errors - The "path" argument must be one of type string, Buffer, or URL. Received type undefined
  • How to create an observable of a stream of infinite items
  • Not efficiently to use multi-Core CPU for training Doc2vec with gensim
  • webGL gl_Position value saving outside shaders
  • Is it okay for a resolver to have side effects besides resolving the type?
  • Move 32bit register into a 8 bit register
  • Is there a way to update, not overwrite, worker_env for a Dask YarnCluster within a script?
  • Lotus Notes Deployment
  • How Do I Add Active Directory To APIM Using Terraform?
  • How to get the old parameter values in Blazor OnParameterSet?
  • How to debug "ERROR: Could not reach the worker node."?
  • How chain indefinite amount of flatMap operators in Reactor?
  • extract dates and times from string in Redshift
  • How do I make a column of 3 cards match in height in bootstrapVue?
  • how to replace missing values from another column in PySpark?
  • only read last line of text file (C++ Builder)
  • Snakemake --forceall --dag results in mysterius Error: <stdin>: syntax error in line 1 near 'File' from Graphvis
  • How Can I Remove Demo Products From APIM Created With Terraform?
  • How to avoid cloning a big integer in rust
  • Break a row of words into word groups in Hive
  • How can I add a path variable to existing files in an Installshield project converted from MSI
  • Certain languages are not available in postman; is there a way to enable it?
  • Concatenation step of U-Net for unequal number of channels
  • HL Fabric - states, transactions but varied keys
  • How to handle "flood wait" errors when using telethon.sync?
  • Any way to make closure which takes a destructured array?
  • What is the Difference between @PeculiarVentures 's `webcrypto` and `node-webcrypto-ossl`?
  • DWG Sheet Combination failing on AutoDesk Forge
  • karate.log(args) on afterScenario hook is not embedded on surefire json file
  • How do I output latest distinct values of specific fields and all other colums?
  • Clarification on lit-element components and where to browse them
  • Will websockets over HTTP2 also be multiplexed in streams?
  • How to apply switch statement for multi columns in datatables
  • frobot framework - Usage outside testing
  • How do I build against the UCRT with mingw-w64?
  • How to use someClass.android.ts and someClass.ios.ts without errors
  • ADB Connection to Samsung smart tv
  • is there a way to 2 create multiple command files in cypress
  • Best way to filter DBpedia results and return a specific results using SPARQL
  • Is it possible to use unicode combining characters to combine arbitrary characters?
  • Antlr4 extremely simple grammar failing
  • Neighbor of 10 wrong answer?
  • PDFlib - setting stroke and fill opacity (transparency)
  • AWS Lambda + Serverless, where/how to deploy js module that couldn't be bundled?
  • how to place mobile call from PWA
  • How to get connected clients and client certificate in node-opcua server
  • Passing dictionary from one template to another in Helm
  • Kivy. Position of GridLayout inside ScrollView
  • How can I try to place a pending order every X minutes till it's successfull?
  • Is there a way to download the SonarLint report generated in Eclipse IDE?
  • How to Open Port in Windows Firewall using C++ Builder?
  • How to put "OR" operator in Karate API assertion statement
  • Get .model.json as String
  • Proof Process busy on combine_split
  • Does memoization work on smple .select with strings?
  • Check if movement ended
  • shadow
    Privacy Policy - Terms - Contact Us © scrbit.com