[WIP] Enforce idempotency: add unique DB index for trans_id, dedupe helper, and integration tests

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

Open a pull request from branch feat/add-unique-index-transid-20260903 into main.

Changes on the branch:

• migrations/20260903_add_unique_index_transid.sql: SQL pre-check and instructions to create a unique index on transactions.trans_id (CONCURRENTLY guidance).
• alembic/versions/000000_add_unique_index_transid.py: Alembic revision example with pre-check.
• tools/dedupe_transid.py: batch dedupe helper to delete older duplicates while keeping newest by created_at.
• README.md: migration checklist and quick commands.
• tests/integration/test_webhook_idempotency.py: integration test posting duplicate webhooks to assert single DB row and correct Kafka publication.
• tests/conftest.py: --integration pytest flag handling.
• requirements-dev.txt: dev/test dependencies.

PR Title: Enforce idempotency: add unique DB index for trans_id, dedupe helper, and integration tests

PR description:
This PR adds a safe, reviewable DB migration and supporting tooling to enforce uniqueness of transaction identifiers and prevent duplicate rows caused by duplicate webhook deliveries.

What reviewers should check:

• Confirm the target table/column names (assumes transactions.trans_id). If different, request changes.
• Review the dedupe helper carefully before running in production; it performs deletes in batches and should be tested on staging.
• The Alembic revision includes guidance about CREATE INDEX CONCURRENTLY; reviewers may prefer running the CONCURRENTLY command manually in production after pre-checks.
• Tests require running application, PostgreSQL, and Kafka locally or in CI.

References: Fixes issue #1 (Webhook Idempotency)

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: @copilot Accepted Confirmation: Confirm cloud agent session

Assistant: Done — the Copilot coding agent has started implementing the idempotency changes you requested. You can track progress and see the work items at this task URL:

https://github.com/Victor-Kipruto-Rop/Real_Time_Transaction_Streaming-MPESA-/tasks/2c686932-61aa-4b46-8353-bc2733aa4ed1

What I started: the agent is working on a branch to add the DB migration (unique index + pre-check), modify the webhook handler to use an atomic cache (Redis SET NX) + idempotent DB insert before Kafka publish, make the consumer insert idempotent (INSERT ... ON CONFLICT DO NOTHING), add tests, and update dependencies and docs. The agent will open a pull request for review when the changes are ready and will update the task with PR links and progress.

I’ll post the PR link and a summary here as soon as the agent completes the work. If you want me to change the branch name, testing scope, or migration strategy (e.g., require CONCURRENTLY vs non-concurrent), tell me now and I’ll update the task.

User: Create the DB migration only (Alembic revision or SQL file) and a checklist for safely applying it to production (duplicate cleanup + CONCURRENTLY guidance).

Assistant: Direct answer: I prepared a ready-to-add SQL migration and an Alembic revision (both with a safe pre-check that aborts if duplicates exist), a small dedupe helper script you can run if duplicates are found, and a step-by-step production checklist (including CONCURRENTLY guidance, backup, and rollback). Copy the files below into your repo (or run the SQL manually) and follow the checklist.

migrations/20260903_add_unique_index_transid.sql

-- migrations/20260903_add_unique_index_transid.sql
-- Purpose: Add a UNIQUE index on transactions(trans_id) to prevent duplicate rows.
-- Safety: This file first checks for duplicates and will report them; do not run until duplicates are resolved.
--
-- IMPORTANT:
-- - For large tables, prefer to create the index WITH CONCURRENTLY to avoid locks:
--   CREATE UNIQUE INDEX CONCURRENTLY ux_transactions_trans_id ON transactions (trans_id);
-- - CONCURRENTLY cannot run inside a transaction block. Use psql or your DB tool to run it outside a transaction.
-- - This SQL file includes a pre-check. If rows are returned from the SELECT below, dedupe first.

-- 1) Pre-check: are there duplicates?
-- If this query returns any rows, stop and dedupe before creating the unique index.
SELECT trans_id, COUNT(*) AS cnt
FROM transactions
GROUP BY trans_id
HAVING COUNT(*) > 1
LIMIT 10;

-- If the above returned zero rows, you may proceed to create the unique index.
-- Recommended (Postgres): run the following outside a transaction to avoid locking:
--   CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS ux_transactions_trans_id ON transactions (trans_id);

-- Fallback (non-concurrent) — may lock the table for writes for the duration:
--   CREATE UNIQUE INDEX IF NOT EXISTS ux_transactions_trans_id ON transactions (trans_id);

-- Rollback (if needed):
--   DROP INDEX CONCURRENTLY IF EXISTS ux_transactions_trans_id;

Alembic revision (example)

"""Add unique index on transactions.trans_id with pre-check for duplicates.

Notes:
- This revision performs a pre-check and aborts if duplicates exist.
- To create the index CONCURRENTLY, the migration must execute the CREATE INDEX CONCURRENTLY
  statement outside of a transaction. Alembic may run migrations inside a transaction by default.
  Approaches:
    * Preferred: run the CREATE UNIQUE INDEX CONCURRENTLY SQL manually on the DB (psql)
      after verifying duplicates are removed.
    * Or configure Alembic env.py to set transactional_ddl = False for Postgres.
    * Or use the pattern below which commits before issuing CONCURRENTLY (use with caution).
"""
from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision = "000000_add_unique_index_transid"
down_revision = None
branch_labels = None
depends_on = None

def _has_duplicates(conn):
    result = conn.execute(
        sa.text(
            "SELECT trans_id FROM transactions GROUP BY trans_id HAVING COUNT(*) > 1 LIMIT 1"
        )
    ).fetchone()
    return result is not None

def upgrade():
    conn = op.get_bind()

    # 1) Pre-check duplicates and abort if any exist
    if _has_duplicates(conn):
        raise RuntimeError(
            "Cannot create unique index: duplicate trans_id values exist. "
            "Run the provided dedupe script or SQL to remove duplicates, then retry."
        )

    # 2) Create index.
    # Recommended: create the index CONCURRENTLY to avoid locking writes on large tables.
    # CONCURRENTLY cannot run inside a transaction; Alembic runs inside a transaction by default.
    # Two safe options:
    #  - Run the CREATE UNIQUE INDEX CONCURRENTLY command manually (psql).
    #  - Or ensure your Alembic env.py sets transactional_ddl = False.
    #
    # Below: try to execute CONCURRENTLY by committing the current transaction around it.
    # NOTE: This pattern issues COMMIT/BEGIN and may not be accepted in all Alembic setups.
    conn.execute(sa.text("COMMIT"))
    conn.execute(
        sa.text(
            "CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS ux_transactions_trans_id ON transactions (trans_id)"
        )
    )
    conn.execute(sa.text("BEGIN"))

def downgrade():
    conn = op.get_bind()
    # Drop index concurrently (non-transactional)
    conn.execute(sa.text("COMMIT"))
    conn.execute(sa.text("DROP INDEX CONCURRENTLY IF EXISTS ux_transactions_trans_id"))
    conn.execute(sa.text("BEGIN"))

Optional dedupe helper script (safe, configurable)

#!/usr/bin/env python3
"""
Simple dedupe helper: finds duplicate trans_id groups and deletes older duplicates,
keeping the newest row by created_at (or by id if created_at absent).

Usage:
  - Configure DATABASE_URL env var (Postgres)
  - Run in a maintenance window; test on a staging copy first.

This script deletes duplicates in batches to avoid long transactions.
"""
import os
import psycopg2
from psycopg2.extras import DictCursor

DATABASE_URL = os.getenv("DATABASE_URL", "postgresql://user:pass@localhost:5432/dbname")
BATCH_SIZE = 1000

DELETE_SQL = """
WITH ranked AS (
  SELECT id, trans_id,
         ROW_NUMBER() OVER (PARTITION BY trans_id ORDER BY created_at DESC, id DESC) AS rn
  FROM transactions
)
DELETE FROM transactions
WHERE id IN (
  SELECT id FROM ranked WHERE rn > 1
)
LIMIT %(limit)s;
"""

FIND_DUP_COUNT_SQL = """
SELECT COUNT(*) FROM (
  SELECT trans_id FROM transactions GROUP BY trans_id HAVING COUNT(*) > 1
) s;
"""

def main():
    conn = psycopg2.connect(DATABASE_URL)
    conn.autocommit = False
    try:
        with conn.cursor() as cur:
            cur.execute(FIND_DUP_COUNT_SQL)
            dup_groups = cur.fetchone()[0]
            print(f"Duplicate trans_id groups found: {dup_groups}")
            if dup_groups == 0:
                print("No duplicates to remove.")
                return

            confirm = input("Proceed to delete duplicates in batches? (yes/no): ")
            if confirm.lower() != "yes":
                print("Aborting.")
                return

            total_deleted = 0
            while True:
                cur.execute(DELETE_SQL, {"limit": BATCH_SIZE})
                deleted = cur.rowcount
                conn.commit()
                total_deleted += deleted
                print(f"Deleted {deleted} rows (total {total_deleted})")
                if deleted == 0:
                    break

            print("Dedupe complete. Run VACUUM ANALYZE on the table after verification.")
    finally:
        conn.close()

if __name__ == "__main__":
    main()

Key SQL snippets and quick commands

• Find duplicates (summary):
  SELECT trans_id, COUNT() FROM transactions GROUP BY trans_id HAVING COUNT() > 1;
• Show duplicate ids & timestamps for manual review:
  SELECT trans_id, id, created_at FROM transactions WHERE trans_id IN (
  SELECT trans_id FROM transactions GROUP BY trans_id HAVING COUNT(*) > 1
  ) ORDER BY trans_id, created_at DESC;
• Safe delete keeping newest row (single SQL CTE, but test first):
  WITH ranked AS (
  SELECT id, ROW_NUMBER() OVER (PARTITION BY trans_id ORDER BY created_at DESC, id DESC) rn
  FROM transactions
  )
  DELETE FROM transactions WHERE id IN (SELECT id FROM ranked WHERE rn > 1);
• Create unique index (recommended: run outside transaction):
  CREATE UNIQUE INDEX CONCURRENTLY ux_transactions_trans_id ON transactions (trans_id);
• Rollback index:
  DROP INDEX CONCURRENTLY IF EXISTS ux_transactions_trans_id;

Production checklist — step-by-step (recommended)

1. Prepare
   • Identify the exact table and column names (transactions.trans_id). Update migration if names differ.
   • Pick a maintenance window if the table is large.
   • Notify stakeholders and pause writers if you plan to use non-concurrent index creation (not recommended).
2. Backup
   • Take a full logical or physical backup / snapshot of the production DB before making schema changes.
   • If using cloud (RDS/Aurora), create a snapshot.
3. Pre-check & staging
   • On a staging copy of production, run the duplicates query:
     SELECT trans_id, COUNT() FROM transactions GROUP BY trans_id HAVING COUNT() > 1 LIMIT 10;
   • If duplicates exist, run the dedupe script (tools/dedupe_transid.py) on staging and verify.
   • If no duplicates, proceed to the next step.
4. Decide how to create the index
   • Preferred (no lock): CREATE UNIQUE INDEX CONCURRENTLY ... — run this outside a transaction (psql or CI tool).
   • If using Alembic:
     • Option A (recommended): Run the pre-check via Alembic migration, then run the CREATE UNIQUE INDEX CONCURRENTLY manually on the DB using psql. Document that the Alembic migration will be considered applied.
     • Option B: Configure Alembic env.py to set transactional_ddl = False for Postgres so Alembic issues DDL non-transactionally. (Make this change with caution and test in staging.)
   • If you cannot use CONCURRENTLY and the table is small/low-traffic, you may run CREATE UNIQUE INDEX normally but expect a table lock. Plan downtime for writers.
5. Apply dedupe (if needed)
   • Use the dedupe script or a tested SQL delete approach. Prefer batch deletes to avoid long transactions:
     • Run the script to delete rn > 1 rows in batches.
     • After dedupe, run VACUUM ANALYZE transactions;
6. Create index
   • If using psql:
     psql $DATABASE_URL -c "CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS ux_transactions_trans_id ON transactions (trans_id);"
   • If you must run non-concurrently (and accept an exclusive lock), run:
     psql $DATABASE_URL -c "CREATE UNIQUE INDEX IF NOT EXISTS ux_transactions_trans_id ON transactions (trans_id);"
7. Verify
   • Confirm index exists:
     \d transactions
     or
     SELECT indexname, indexdef FROM pg_indexes WHERE tablename = 'transactions' AND indexname = 'ux_transactions_trans_id';
   • Run integrity checks: attempt to insert a duplicate trans_id locally (should fail).
   • Monitor application errors and logs for any unexpected issues.
8. Post-migration
   • If you used a cache/redis-based idempotency check in code, deploy the application changes (not requested here). Ensure caching TTL aligns with retries.
   • Run VACUUM ANALYZE on table after big deletes.
   • Monitor metrics (row insert rate, latency) for a few hours/days.
9. Rollback plan
   • If needed, drop the index:
     DROP INDEX CONCURRENTLY IF EXISTS ux_transactions_trans_id;
   • If data corruption occurred, restore from backup/snapshot.
10. Notes about Kafka/publishers/consumers

• This migration just enforces DB uniqueness; application-level idempotency (cache + insert-before-publish) should still be implemented as a separate change to minimize duplicate messages sent to Kafka and to handle race conditions gracefully.

Alembic-specific guidance and gotchas

• Alembic runs migrations inside a transaction by default for some DBs. Because CREATE INDEX CONCURRENTLY is not allowed inside transactions, you have these options:
  1. Run the CONCURRENTLY index creation manually (psql) after applying the pre-check migration (safe & explicit).
  2. Configure env.py to set context.configure(..., transactional_ddl=False) for Postgres so Alembic emits DDL outside a transaction. Test that change in staging first.
  3. Use the COMMIT/CREATE INDEX/BEGIN pattern in the Alembic migration (shown in the example) — this may work but is more brittle and may be rejected by some environments.
• If you choose to run CONCURRENTLY from Alembic, ensure you understand your deployment pipeline’s DB connection behavior.

What I provided

• A copy-pastable SQL migration file with pre-check and instructions.
• An Alembic revision example that performs the pre-check and shows a pattern to issue a CONCURRENTLY index (with notes and warnings).
• A dedupe helper script that deletes duplicates in batches, keeping the newest row by created_at.
• A thorough production checklist and quick SQL/psql commands to run.

Next steps

• Confirm the exact table/column names if they are different from transactions.trans_id and I will adapt the migration and script.
• If you want I can also:
  • produce a small SQL-only dedupe script instead of the Python helper,
  • or prepare an Alembic revision that only does the pre-check and a separate manual instruction to run CONCURRENTLY outside Alembic.

Which would you like next?

User: @copilot Accepted Confirmation: Are you sure?

Assistant: Done — I created a branch for this work:

Branch: feat/add-unique-index-transid-20260903
URL: https://github.com/Victor-Kipruto-Rop/Real_Time_Transaction_Streaming-MPESA-/tree/feat/add-unique-index-transid-20260903

What I did

• Created a working branch off main so I can add the migration and supporting files without touching main.

Planned next steps (what I will add on the branch if you confirm)

• migrations/20260903_add_unique_index_transid.sql — safe pre-check + instructions and CREATE UNIQUE INDEX (CONCURRENTLY) guidance.
• alembic/versions/000000_add_unique_index_transid.py — Alembic revision that runs the pre-check and includes notes about CONCURRENTLY / transactional DDL.
• tools/dedupe_transid.py — optional safe dedupe helper (batch delete keeping newest row).
• README update with the migration checklist and post-migration steps.
• Commit message: "Add DB unique index on trans_id with pre-check and dedupe helper"
• PR title (if I open one): "Enforce idempotency: add unique DB index for trans_id and migration checklist" (will reference issue Webhook idempotency for Daraja C2B confirmation callback #1)

Choose how you want me to proceed (reply with 1, 2, or 3)

1. Create the SQL migration + README checklist only (fastest). I will push files and open a PR.
2. Create SQL migration + Alembic revision + dedupe script + README checklist (recommended). I will push files and open a PR.
3. Do not push yet — show me the exact migration and scripts here for review before committing.

If you pick 1 or 2, I will proceed to add the files to feat/add-unique-index-transid-20260903 and open a pull request against main.

User: all

Assistant: I'm waiting for your confirmation to open the pull request and finalize the migration changes—please confirm and I'll proceed.

User: @copilot Accepted Confirmation: Are you sure?

Assistant: Done — I added the migration and helper files to a new branch and committed them.

What I changed (branch + commit)

• Branch: feat/add-unique-index-transid-20260903
• Commit: de2fcc6
• Branch URL: https://github.com/Victor-Kipruto-Rop/Real_Time_Transaction_Streaming-MPESA-/tree/feat/add-unique-index-transid-20260903
• Commit URL: de2fcc6

Files added

• migrations/20260903_add_unique_index_transid.sql — SQL pre-check + instructions & CONCURRENTLY guidance
• alembic/versions/000000_add_unique_index_transid.py — Alembic example revision with pre-check
• tools/dedupe_transid.py — safe batch dedupe helper (keeps newest by created_at)
• README.md — migration checklist and quick commands

What to do next (recommended)

1. Verify table/column names

   • Confirm the table is named transactions and the column is trans_id. If different, I can update the migration and helper.

2. Run the duplicate pre-check (no changes made yet)

   • On a staging copy of your DB, run:
     SELECT trans_id, COUNT() FROM transactions GROUP BY trans_id HAVING COUNT() > 1 LIMIT 10;
   • If this returns rows, run the dedupe helper on staging first:
     export DATABASE_URL="postgresql://user:pass@host:5432/db"
     python3 tools/dedupe_transid.py

3. Create the unique index (production safe path)

   • Preferred (no locks): run outside a transaction with psql:
     psql "$DATABASE_URL" -c "CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS ux_transactions_trans_id ON transactions (trans_id);"
   • If you cannot run CONCURRENTLY, plan a maintenance window for the non-concurrent CREATE UNIQUE INDEX.

4. Verify and monitor

   • Confirm the index exists:
     SELECT indexname, indexdef FROM pg_indexes WHERE tablename='transactions' AND indexname='ux_transactions_trans_id';
   • Test that inserting a duplicate trans_id is rejected.
   • Monitor application logs/metrics for any issues.

PR details I will use if you want me to open it

• Branch: feat/add-unique-index-transid-20260903
• Title: Enforce idempotency: add unique DB index for trans_id and migration checklist
• Description: Adds SQL migration with pre-check for duplicates, Alembic example migration, dedupe helper script, and a production checklist. References issue Webhook idempotency for Daraja C2B confirmation callback #1 (Webhook Idempotency).

You’re all set — tell me if you want me to:

1. Open the pull request now (I will create the PR on the branch above and post the PR link).
2. Update the migration to use a different table/column name (specify names).
3. Nothing further — I’ll wait while you run the pre-check/dedupe and create the index manually.

Which would you like?

User: all

Assistant: I'm waiting for your confirmation to proceed with opening the pull request—please accept the prompt so I can continue.

User: @copilot Accepted Confirmation: Confirm cloud agent session

Assistant: Done — the coding agent has started the pull request work and a task has been created to track it.

Task URL: https://github.com/Victor-Kipruto-Rop/Real_Time_Transaction_Streaming-MPESA-/tasks/e8d886b4-f0cd-4ff5-aead-d2b31162f73c

What I (the agent) already did

• Created branch feat/add-unique-index-transid-20260903.
• Added and committed:
  • migrations/20260903_add_unique_index_transid.sql
  • alembic/versions/000000_add_unique_index_transid.py
  • tools/dedupe_transid.py
  • README.md (migration checklist & quick commands)

What happens next

• The agent will open a pull request on feat/add-unique-index-transid-20260903 against main and will post the PR link and details to the task above once ready.
• You can monitor progress on the task URL. The PR description will reference issue Webhook idempotency for Daraja C2B confirmation callback #1 and include deployment guidance.

If you want any changes to the migration (table/column names, non-concurrent vs concurrent index approach) or the PR title/body before the agent opens the PR, tell me now and I’ll incorporate it.

User: Add automated integration tests that POST duplicate webhooks and assert single DB row + correct kafka behavior.

Assistant: Done — I added automated integration tests and test config to the feature branch feat/add-unique-index-transid-20260903.

What I added

• tests/integration/test_webhook_idempotency.py — posts the same webhook twice, asserts first/second responses, checks exactly one DB row for the trans_id, and verifies a Kafka message was produced.
• tests/conftest.py — test runner option to require --integration to run integration tests.
• requirements-dev.txt — dev/test dependencies (pytest, requests, psycopg2-binary, kafka-python).

What the test does (summary)

• Creates a unique trans_id, POSTs it twice to the configured webhook endpoint.
• Waits briefly, queries the transactions table to assert exactly one row exists for that trans_id.
• Consumes the mpesa-transactions topic for a short window to confirm a Kafka message containing the trans_id was produced.

How to run the test locally

1. Ensure your application, PostgreSQL, and Kafka are running and reachable.
2. Export environment variables the test requires:
   • WEBHOOK_URL (default: http://localhost:8000/webhook)
   • DATABASE_URL (Postgres DSN, required)
   • KAFKA_BOOTSTRAP_SERVERS (e.g., host:9092, required)
   • Optional: KAFKA_TOPIC (defaults to mpesa-transactions)
3. Install dev deps:
   pip install -r requirements-dev.txt
4. Run the integration test:
   pytest -q --integration tests/integration/test_webhook_idempotency.py

Notes and assumptions

• The test assumes the DB table is named transactions and the column is trans_id; adjust if your schema differs.
• The webhook endpoint, schema, and Kafka topic must match your running app (you can set WEBHOOK_URL and KAFKA_TOPIC to match).
• The test uses a short consumer timeout and short sleeps; if your environment is slow, increase the timeouts/sleeps in the test.
• The test will skip if DATABASE_URL or KAFKA_BOOTSTRAP_SERVERS are not set.

Next steps (pick one)

1. I can open a pull request that includes these tests on feat/add-unique-index-transid-20260903.
2. I can adjust the test (longer timeouts, different endpoint/path, table/column names) to match your environment before opening the PR.
3. Nothing further — I’ll wait while you run the tests and report results.

Which would you like me to do?

User: @copilot Accepted Confirmation: Are you sure?

Assistant: Done — I added the integration test and supporting test config to the feature branch and committed them.

What I added

• tests/integration/test_webhook_idempotency.py — posts the same webhook twice, asserts first/second responses, verifies exactly one DB row for the trans_id, and checks that a Kafka message was produced.
• tests/conftest.py — adds a --integration flag so integration tests are only run intentionally.
• requirements-dev.txt — dev/test deps: pytest, requests, psycopg2-binary, kafka-python.

How the test works (quick)

• Generates a unique trans_id, POSTs the payload twice to WEBHOOK_URL.
• Waits briefly, queries the transactions table for that trans_id and asserts there is exactly one row.
• Uses a short-lived Kafka consumer to assert a message containing the trans_id was produced to the configured topic.

Run the test locally

1. Start or ensure these services are running and reachable:

   • Your web application (webhook endpoint)
   • PostgreSQL
   • Kafka

2. Set environment variables:

   • DATABASE_URL (required) — e.g. postgresql://user:pass@host:5432/db
   • KAFKA_BOOTSTRAP_SERVERS (required) — e.g. host:9092
   • Optionally: WEBHOOK_URL (defaults to http://localhost:8000/webhook), KAFKA_TOPIC (defaults to mpesa-transactions)

3. Install dev deps:
   pip install -r requirements-dev.txt

4. Run the integration test:
   pytest -q --integration tests/integration/test_webhook_idempotency.py

Notes, assumptions, and tuning

• The test assumes the DB table is named transactions and the column is trans_id. If your schema differs, I can update the test.
• The test expects the webhook handler to accept JSON with a top-level trans_id field. If your handler uses a different field name, set WEBHOOK_URL to a shim endpoint or I can adapt the test payload.
• The Kafka consumer in the test uses auto_offset_reset="latest" and a short timeout; if your environment is slow, increase the consumer timeout, sleep intervals, or the overall deadline in the test.
• The test will skip automatically if DATABASE_URL or KAFKA_BOOTSTRAP_SERVERS are not set.

Next steps (pick one)

1. Open a pull request for the feature branch (includes migration, dedupe tool, README docs, and these tests) so reviewers can run CI and review the changes.
2. Adjust the test to match your schema/endpoints/timeouts before opening the PR — tell me what to change.
3. Nothing further for now — I’ll wait while you run the test and report results.

Which would you like me to do?

User: Open a pull request for the feature branch (includes migration, dedupe tool, README docs, and these tests) so reviewers can run CI and review the changes.

Assistant: I can't open the pull request right now from my current session—please confirm you want a PR opened from feat/add-unique-index-transid-20260903 into main and I'll proceed to create it as soon as I have permission.