Allow using temporary staging path in Iceberg for writing sorted files

[agoyal-sfdc]

Description

This change adds support for using temporary staging directory during write operations involving sorted tables. Writes to sorted tables will utilize this path for staging temporary files during sorting operation. When disabled, the target storage will be used for staging while writing sorted tables which can be inefficient when writing to object stores like S3.

Adding session properties for these, as well as for the properties that control the number and target size of buffer files. This is useful because files of different sizes/number can be configured per query, so they can be tuned for the type of data in a given table.

Additional context and related issues

Fixes #24376
Similar to functionality added for Hive in #3434

Release notes

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## Iceberg
* Support using temporary staging path for writing sorted files. ({[issue](https://github.com/trinodb/trino/issues/24376)}`24376`)

[Copilot]

Pull Request Overview

Adds support for a configurable temporary staging directory when writing sorted files in Iceberg, improving performance on object stores.

• Introduces temporaryStagingDirectoryEnabled and temporaryStagingDirectoryPath in IcebergConfig and exposes them as session properties.
• Updates IcebergSessionProperties and IcebergPageSink to select between the staging directory and default temp path per session.
• Expands tests and documentation to cover the new staging directory behavior.

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergConfig.java	Add new config properties and their setters/getters
plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergSessionProperties.java	Register new session properties and provide accessors
plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergPageSink.java	Implement logic to choose staging directory or default temp path
plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergPageSinkProvider.java	Remove unused SortingFileWriterConfig injection
plugin/trino-iceberg/src/test/java/io/trino/plugin/iceberg/*.java	Update tests to include SortingFileWriterConfig and new session props
docs/src/main/sphinx/connector/iceberg.md	Document the new temporary staging directory properties

Comments suppressed due to low confidence (2)

plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergConfig.java:90

• [nitpick] The field name includes the 'is' prefix which duplicates the boolean getter style. Consider renaming it to temporaryStagingDirectoryEnabled to avoid confusion between field and getter naming.

    private boolean isTemporaryStagingDirectoryEnabled;

docs/src/main/sphinx/connector/iceberg.md:220

• [nitpick] The list formatting uses * - which differs from surrounding items. Align these entries with the existing Sphinx list style for consistency and readability.

* - `iceberg.temporary-staging-directory-enabled`

[Copilot]

[nitpick] Concatenating the scheme with the path may produce extra slashes (e.g., file:////tmp/...). Consider using a URI builder or checking if the path already starts with a '/' to normalize to a single 'file://' prefix.

Suggested change

	return Location.of("file:///" + location.path());
	String normalizedPath = location.path().startsWith("/") ? "file://" + location.path() : "file:///" + location.path();
	return Location.of(normalizedPath);

[agoyal-sfdc]

This is identical to the function in HiveWriterFactory:

trino/plugin/trino-hive/src/main/java/io/trino/plugin/hive/HiveWriterFactory.java

Lines 685 to 691 in 5b81408

	static Location setSchemeToFileIfAbsent(Location location)
	{
	if (location.scheme().isPresent()) {
	return location;
	}
	return Location.of("file:///" + location.path());
	}