Operator output port result cache (MVP)

[Xiao-zhen-Liu]

Feature Summary

Texera runs a workflow from the start every time, even when the user changed only one operator near the end. This adds an operator output port result cache: on a re-run, an output port whose upstream computation is unchanged reads its saved result instead of recomputing it, for faster iteration.

The MVP always reuses a matched port's result (full reuse); there is no cost-based reuse decision and no eviction, which are future work. When no port is matched, the system behaves exactly as today, so the work can land inactive and turn on once results are saved.

Design and rationale: Discussion #5880.

Proposed Solution or Design

This umbrella issue tracks the tasks that deliver the feature (the sub-issues below). They are independent units of work; each changes behavior only when a cache result is matched, so each can be reviewed on the guarantee that an empty cache reproduces current behavior. Real prerequisites are noted in each task.

• Add operator output port cache storage (table and cache key) #5882 Add the cache storage layer (table, DAO, cache key).
• Carry operator cache-reuse status to the frontend and handle cached-region statistics #5883 Carry cache-reuse status in operator metrics and handle cached-region statistics.
  • feat(amber): carry cache-reuse status as a metrics flag #6729
• Add cache-reuse planning to the scheduler (skeleton generation and schedule assembly) #5884 Add cache-reuse planning to the scheduler (skeleton generation and schedule assembly).
• Wire cache lookup, result saving, REST endpoints, and cleanup into execution #5885 Wire cache lookup, result saving, REST endpoints, and cleanup into execution.
• Add cache panel and canvas display to the workflow editor #5886 Add the cache panel and canvas display to the workflow editor.

Notes:

• Generated code (jOOQ for the table, protobuf for the metrics flag) is not committed; the changes ship the source and the build regenerates the rest.
• The implementation is re-derived from the prototype branch onto current main, not merged from it directly.

Affected Area

Workflow Engine (Amber), Storage / Metadata, Workflow UI