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@xi-db xi-db commented Oct 13, 2025

What changes were proposed in this pull request?

Spark Connect is a decoupled client-server architecture that allows remote connectivity to Spark clusters using the DataFrame API and unresolved logical plans as the protocol, which is well documented in https://spark.apache.org/docs/latest/spark-connect-overview.html.

However, there is a lack of guidance to help users understand the behavioral differences between Spark Classic and Spark Connect and to avoid unexpected behavior.

In this PR, a document is added that details the behavioral differences between Spark Connect and Spark Classic, lazy schema analysis and name resolution, and their implications.

Why are the changes needed?

This doc helps users migrating from Spark Classic to Spark Connect to understand the behavioral differences.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

N/A.

Was this patch authored or co-authored using generative AI tooling?

No.

@xi-db xi-db changed the title Add documentation comparing behavioral differences between Spark Connect and Spark Classic [SPARK-53882][CONNECT][DOC] Add documentation comparing behavioral differences between Spark Connect and Spark Classic Oct 13, 2025
@xi-db xi-db changed the title [SPARK-53882][CONNECT][DOC] Add documentation comparing behavioral differences between Spark Connect and Spark Classic [SPARK-53882][CONNECT][DOCS] Add documentation comparing behavioral differences between Spark Connect and Spark Classic Oct 13, 2025
limitations under the License.
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The comparison highlights key differences between Spark Connect and Spark Classic in terms of execution and analysis behavior. While both utilize lazy execution for transformations, Spark Connect emphasizes deferred schema analysis, introducing unique considerations like temporary view handling and UDF evaluation. The guide outlines common gotchas and provides strategies for mitigation.
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, Spark Connect emphasizes deferred schema analysis -> , Spark Connect also defers analysis/, Spark Connect analyzes lazily

try to avoid too much indirection.


**When does this matter?** These differences are particularly important when migrating existing code from Spark Classic to Spark Connect, or when writing code that needs to work with both modes. Understanding these distinctions helps avoid unexpected behavior and performance issues.

**Note:** The examples in this guide use Python, but the same principles apply to Scala and Java.
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Please be a champ and also add Scala/Java

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