docs: add write.intermediate.interval.seconds parameter for Redshift/Snowflake sinks

[Copilot]

Description

Documents the new two-tier write scheduling introduced for Redshift and Snowflake v2 sinks. The feature decouples COPY INTO operations from barriers, enabling independent control of intermediate storage writes and target table merges.

Parameter additions:

• write.intermediate.interval.seconds (default: 1800s) - controls S3 write frequency
• Updated write.target.interval.seconds description - clarifies it controls target table merge frequency

Behavior changes documented:

• Background async threads run periodic COPY INTO operations
• Separate thread runs periodic MERGE INTO for CDC operations
• Two-tier scheduling allows optimizing S3 writes independently from table merges

Both Redshift and Snowflake v2 documentation updated with consistent parameter tables and upsert mode explanations.

Related code PR

risingwavelabs/risingwave#23086

Related doc issue

https://github.com/risingwavelabs/risingwave-docs/issues/[issue-number]

Checklist

• I have run the documentation build locally to verify the updates are applied correctly.
• For new pages, I have updated mint.json to include the page in the table of contents.
• All links and references have been checked and are not broken.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Document: feat(sink): support copy into wihout barrier for redshift</issue_title>
<issue_description>This issue tracks the documentation update needed for the merged PR risingwavelabs/risingwave-docs#23086.

Source PR URL: risingwavelabs/risingwave#23086
Source PR Merged At: 2026-02-02T07:56:08Z

If it is a major improvement that deserves a new page or a new section in the documentation, please check if we should label it as an experiment feature.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Document: feat(sink): support copy into wihout barrier for redshift #920

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[Copilot]

Pull request overview

This PR updates the Redshift and Snowflake v2 sink documentation to describe the new two-tier write scheduling mechanism and the new write.intermediate.interval.seconds parameter.

Changes:

• Added write.intermediate.interval.seconds (default 1800s) to the Redshift and Snowflake v2 sink option tables to document configurable intermediate storage write frequency.
• Clarified that write.target.interval.seconds controls target table write/merge frequency, and expanded the upsert-mode descriptions to explain separate intervals for intermediate storage writes and target table merges.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
integrations/destinations/snowflake-v2.mdx	Documents separate intervals for writing to S3-based intermediate storage and for merging into the Snowflake target table, including the new write.intermediate.interval.seconds parameter.
integrations/destinations/redshift.mdx	Mirrors the Snowflake v2 updates for Redshift, adding write.intermediate.interval.seconds and clarifying the role of write.target.interval.seconds in upsert mode.