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Data Engineering
Join discussions on data engineering best practices, architectures, and optimization strategies within the Databricks Community. Exchange insights and solutions with fellow data engineers.
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Forum Posts

guruv
by New Contributor III
  • 3872 Views
  • 5 replies
  • 1 kudos

Resolved! Saprk UI not showing any running tasks

HI,I am running a Notebook job calling a JAR code (application code implmented in C#). in the Spark UI page for almost 2 hrs, it'w not showing any tasks and even the CPU usage is below 20%, memory usage is very small. Before this 2 hr window it shows...

  • 3872 Views
  • 5 replies
  • 1 kudos
Latest Reply
Kaniz
Community Manager
  • 1 kudos

Hi @guruv​ , Does @Atanu Sarkar​ 's response answer your query?

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sajith_appukutt
by Honored Contributor II
  • 930 Views
  • 1 replies
  • 0 kudos

Resolved! I'm using the Redshift data source to load data into spark SQL data frames. However, I'm not seeing predicate push down for my queries ran on Redshift - is that expected?

I was expecting filter operations to be pushed down to Redshift by the optimizer. However, the entire dataset is getting loaded from Redshift.

  • 930 Views
  • 1 replies
  • 0 kudos
Latest Reply
sajith_appukutt
Honored Contributor II
  • 0 kudos

The Spark driver for Redshift pushes the following operators down into Redshift:FilterProjectSortLimitAggregationJoinHowever, it does not support expressions operating on dates and timestamps today. If you have a similar requirement, please add a fea...

  • 0 kudos
sajith_appukutt
by Honored Contributor II
  • 1441 Views
  • 1 replies
  • 0 kudos

Resolved! Re-optimize in delta not splitting large files to smaller files.

I am trying to re-optimize the a delta table with a max file size of 32 MB. But after changing spark.databricks.delta.optimize.maxFileSize and trying to optimize a partition, it doesn't split larger files to smaller ones. How can i get it to work.

  • 1441 Views
  • 1 replies
  • 0 kudos
Latest Reply
sajith_appukutt
Honored Contributor II
  • 0 kudos

spark.databricks.delta.optimize.maxFileSize controls the target size to binpack files when you run OPTIMIZE command. But it will not split larger files to smaller ones today.  File splitting happens when ZORDER is ran however.

  • 0 kudos
Srikanth_Gupta_
by Valued Contributor
  • 801 Views
  • 2 replies
  • 1 kudos

What are Best Practices for Spark streaming in Databricks

What are best practices for Spark streaming in Databricksis it good idea to consume multiple topics in one streaming jobis Auto scaling recommended for spark streamingHow many worker nodes we should choose for streaming jobWhen should we run OPTIMIZE...

  • 801 Views
  • 2 replies
  • 1 kudos
Latest Reply
craig_ng
New Contributor III
  • 1 kudos

See our docs for other considerations when deploying a production streaming job.

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User16826992666
by Valued Contributor
  • 775 Views
  • 1 replies
  • 0 kudos

Resolved! I know my partitions are skewed, is there anything I can do to help my performance?

I know the skew in my dataset has the potential to cause issues with my job performance, so just wondering if there is anything I can do to help my performance other than repartitioning the whole dataset.

  • 775 Views
  • 1 replies
  • 0 kudos
Latest Reply
sajith_appukutt
Honored Contributor II
  • 0 kudos

For scenarios like this, it is recommend to use a cluster with Databricks Runtime 7.3 LTS or above where AQE is enabled. AQE dynamically handles skew in sort merge join and shuffle hash join by splitting (and replicating if needed) skewed tasks into ...

  • 0 kudos
User16826992666
by Valued Contributor
  • 1266 Views
  • 1 replies
  • 0 kudos

Resolved! What should I be looking for when evaluating the performance of a Spark job?

Where do I start when starting performance tuning of my queries? Are there particular things I should be looking out for?

  • 1266 Views
  • 1 replies
  • 0 kudos
Latest Reply
Srikanth_Gupta_
Valued Contributor
  • 0 kudos

Few things on top of my mind.1) Check Spark UI and check which stage is taking more time.2) Check for data skewing3) Data skew can severely downgrade performance of queries, Spark SQL accepts skew hints in queries, also make sure to use proper join h...

  • 0 kudos
Srikanth_Gupta_
by Valued Contributor
  • 717 Views
  • 1 replies
  • 0 kudos

How does Spark SQL Catalyst optimizer work?

How does Catalyst optimizer improves the performances, what is its role?

  • 717 Views
  • 1 replies
  • 0 kudos
Latest Reply
Srikanth_Gupta_
Valued Contributor
  • 0 kudos

Catalyst optimizer converts unresolved logical plan into executable physical plan, deep dive is available here

  • 0 kudos
User16790091296
by Contributor II
  • 548 Views
  • 0 replies
  • 5 kudos

Some Tips & Tricks for Optimizing costs and performance (Clusters and Ganglia): [Note: This list is not exhaustive] Leverage the DataFrame or Spar...

Some Tips & Tricks for Optimizing costs and performance (Clusters and Ganglia):[Note: This list is not exhaustive]Leverage the DataFrame or SparkSQL API’s first. They use the same execution process resulting in parity in performance but they also com...

  • 548 Views
  • 0 replies
  • 5 kudos
SatheesshChinnu
by New Contributor III
  • 8677 Views
  • 4 replies
  • 0 kudos

Resolved! Error: TransportResponseHandler: Still have 1 requests outstanding when connection, occurring only on large dataset.

I am getting below error only during large dataset(i.e 15 TB compressed) . if my dataset is small( 1TB) i am not getting this error. Look like it fails on shuffle stage. Approx number of mappers is 150,000 Spark config:spark.sql.warehouse.dir hdfs:...

  • 8677 Views
  • 4 replies
  • 0 kudos
Latest Reply
parikshitbhoyar
New Contributor II
  • 0 kudos

@Satheessh Chinnusamy how did you solve the above issue

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WajdiFATHALLAH
by New Contributor
  • 10540 Views
  • 4 replies
  • 0 kudos

Writing large parquet file (500 millions row / 1000 columns) to S3 takes too much time

Hello community,First let me introduce my use case, i daily receive a 500 million rows like so :ID | Categories 1 | cat1, cat2, cat3, ..., catn 2 | cat1, catx, caty, ..., anothercategory Input data: 50 compressed csv files each file is 250 MB ...

  • 10540 Views
  • 4 replies
  • 0 kudos
Latest Reply
EliasHaydar
New Contributor II
  • 0 kudos

So you are basically creating an inverted index ?

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User16826991422
by Contributor
  • 5827 Views
  • 5 replies
  • 0 kudos

Resolved! How do I get a cartesian product of a huge dataset?

A cartesian product is a common operation to get the cross product of two tables. For example, say you have a list of customers and a list of your product catalog and want to get the cross product of all customer - product combinations. Cartesian pr...

  • 5827 Views
  • 5 replies
  • 0 kudos
Latest Reply
Forum_Admin
Contributor
  • 0 kudos

Hi buddies, it is great written piece entirely defined, continue the good work constantly.

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