fix: optimise OpenSearch query for merge suggestions (CM-1012)

[skwowet]

Summary

• Limit OpenSearch clause expansion in merge suggestion queries by capping fuzzy expansion in both member and organization searches with max_expansions: 3
• Cap organization prefix query expansion with rewrite: 'top_terms_3' to reduce clause growth
• Reduce organization query fan-out by lowering the processed identity cap from 100 to 75 and reducing org identity chunk size from 20 to 15
• Normalize cleaned organization identity values to lowercase so prefix queries stay aligned with the lowercase analyzer used by nested_identities.string_value

---

Note

Medium Risk
Changes OpenSearch query construction for member/org merge suggestions (fuzzy/prefix expansion, chunking, normalization), which can affect both performance and which entities get suggested for merge. Adds a new Temporal workflow for testing org merge suggestions, but it’s non-production unless invoked explicitly.

Overview
Optimizes merge-suggestion OpenSearch queries to reduce clause explosion: caps fuzzy matching with max_expansions: 3 (members + orgs), constrains org prefix queries via rewrite: 'top_terms_3', and lowers org identity fan-out (process up to 75 identities, chunk size 15).

Also normalizes cleaned org identity values to lowercase to better align with the index analyzer, and introduces a testOrganizationMergeSuggestions Temporal workflow (exported from workflows.ts) to fetch organizations by ID and log computed suggestions in parallel.

^{Written by Cursor Bugbot for commit ee8cfa9. This will update automatically on new commits. Configure here.}

[Copilot]

Pull request overview

Optimizes OpenSearch merge-suggestion queries to reduce clause explosion and improve match precision/performance in the merge suggestions worker.

Changes:

• Added expansion caps for fuzzy queries (max_expansions: 3) in both organization and member merge suggestions.
• Limited organization prefix query expansion via rewrite: 'top_terms_3' and reduced org identity query chunk size to 15.
• Switched organization “weak identity” matching from match to match_phrase.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
services/apps/merge_suggestions_worker/src/activities/organizationMergeSuggestions.ts	Tightens org identity query construction (chunk size, fuzzy/prefix expansion limits, weak match change).
services/apps/merge_suggestions_worker/src/activities/memberMergeSuggestions.ts	Caps fuzzy query expansion to reduce query clause growth.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.