chore: optimize SQL queries that perform partial full table scans

[Nov1c444]

Summary

optimize SQL queries that perform partial full table scans
Fix #24784

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[Copilot]

Pull Request Overview

This PR optimizes SQL queries by addressing partial full table scan issues through database indexing improvements and caching strategies to reduce database load. The changes focus on preventing performance bottlenecks caused by frequent database operations.

• Added a database index on workflow_run_id column for the workflow_app_logs table
• Implemented Redis-based caching for provider last used timestamps to reduce database update frequency
• Optimized database deletion operations by using compound indexes and disabling session synchronization

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
api/models/workflow.py	Added database index on workflow_run_id column to optimize query performance
api/migrations/versions/2025_08_29_1534-b95962a3885c_add_workflow_app_log_run_id_index.py	Database migration to create the new workflow run ID index
api/events/event_handlers/update_provider_when_message_created.py	Implemented Redis caching for provider updates with time-window based updates
api/core/rag/index_processor/processor/parent_child_index_processor.py	Optimized deletion queries by using compound indexes and disabling session synchronization
api/core/app/apps/advanced_chat/generate_task_pipeline.py	Removed message event emission to reduce database operations

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[QuantumGhost]

LGTM