[jira] [Created] (FLINK-39302) Handling Idempotency in SHOW CREATE [OR ALTER] for Relative Intervals

["Ramin Gharib (Jira)" <ji...@apache.org>]

Ramin Gharib created FLINK-39302:
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             Summary: Handling Idempotency in SHOW CREATE [OR ALTER] for Relative Intervals
                 Key: FLINK-39302
                 URL: https://issues.apache.org/jira/browse/FLINK-39302
             Project: Flink
          Issue Type: Sub-task
          Components: Table SQL / Planner
            Reporter: Ramin Gharib


When using relative time intervals (such as {{{}FROM_NOW(INTERVAL '7' DAY){}}}) for materialized table start modes, the expression is inherently non-idempotent because its evaluated value changes depending on when the command is run.

To ensure clarity and maintain idempotency for users auditing or recreating tables, the {{SHOW CREATE [OR ALTER] MATERIALIZED TABLE}} command will output the user's original relative expression, but append an inline SQL comment containing the exact timestamp that was resolved at the time of execution.



*Example:* If a user submits: {{START_MODE = FROM_NOW(INTERVAL '7' DAY)}}

The {{SHOW CREATE OR ALTER}} output will render as: {{START_MODE = FROM_NOW(INTERVAL '7' DAY) /* Evaluated to FROM_TIMESTAMP(TIMESTAMP '2025-10-28 10:00:00') at execution */}}

This approach preserves the user's original intent while providing the precise, deterministic timestamp used by the engine.



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