[326] Configure SQLite index structures for database_writer_pool

[Goodnessukaigwe]

Summary

Adds SQLite write-path indexes for database_writer_pool so keyed lookups, updates, and deletes hit an index instead of scanning.

Closes #326

Indexes added or reused

New (migration 7)

• idx_webhook_subscriptions_webhook_url on webhook_subscriptions(webhook_url) — the only write-path lookup that was a full table scan (SELECT/DELETE by URL).

Reused existing named indexes (already justified by other query patterns; not duplicated)

• idx_events_contract_ledger — contract + ledger existence/update probes
• idx_webhook_subscriptions_contract — contract-scoped webhook lookups
• idx_monitored_contracts_active — active-contract filter during read-then-write

Uniqueness / PK indexes left as-is (adding a second B-tree would only slow writes)

• sqlite_autoindex_events_1 — UNIQUE(contract_id, ledger_sequence, event_type)
• sqlite_autoindex_indexer_state_1 — ledger pointer by key
• sqlite_autoindex_monitored_contracts_1 — contract_id keyed updates
• sqlite_autoindex_webhook_subscriptions_1 — (contract_id, webhook_url)
• schema_migrations INTEGER PRIMARY KEY — version lookup at pool start

Lookup patterns

Writer-pool operations do keyed INSERT OR IGNORE, UPDATE … WHERE, DELETE … WHERE, and read-then-write existence checks against events, indexer_state, monitored_contracts, webhook_subscriptions, and schema_migrations.

EXPLAIN QUERY PLAN

After migration 7, every writer-pool lookup is a SEARCH that uses the intended index. Dropping idx_webhook_subscriptions_webhook_url returns the URL lookup to SCAN webhook_subscriptions, proving the new index is load-bearing. No lookup builds a temporary B-tree.

Test plan

• __tests__/database-writer-pool-indexes.test.ts asserts indexes exist, EXPLAIN QUERY PLAN uses them, uniqueness is preserved, and writer-pool writes still succeed
• Existing database-writer-pool suites
• indexer.test.ts migration count updated for version 7
• tsc -p tsconfig.build.json / npm run build

Made with Cursor

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