delta-io/delta

Unable to write metadata to delta table using scala api

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#857 opened on Dec 7, 2021

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 (15 comments) (9 reactions) (2 assignees)Scala (2,159 forks)batch import
enhancementgood first issuestale

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Description

Extension to #321

When using an api like the one below, the only supported method to write metadata is through the use of the sparkSession which works until a single spark session is performing multiple writes simultaneously. In this case, manipulating the spark session still doesn't provide the ability to pass accurate metadata to the table. Could we find a way to ensure metadata writes are possible at the writer level even when using the following syntax? Thanks

cc @zsxwing

DeltaTable.forPath(target.tableLocation).alias("target")
  .merge(updatesDF, mergeCondition)
  .whenMatched
  .updateAll()
  .whenNotMatched
  .insertAll()
  .execute()

Thank you

Contributor guide

Research direction
Investigate how metadata is written during DeltaTable.merge operations. Trace the code path from execute() to see where metadata is set, and identify why the Spark session manipulation doesn't work for concurrent writes. Explore alternatives to provide metadata at the writer level without relying on Spark session config.
Tech stack
scalaspark
Domain
backenddata
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
ScalaSparkDelta Lake
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30