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- 310 registry:skill items, 1528 files, 7 categories (hub tags) - registry.json generated by @kortix/registry buildRegistry - nested SKILL.md in sn-da-* renamed SUBSKILL.md (no phantom skills) - provenance + licenses: SOURCES.md
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1.3 KiB
| title | impact | impactDescription | tags |
|---|---|---|---|
| Use Covering Indexes to Avoid Table Lookups | MEDIUM-HIGH | 2-5x faster queries by eliminating heap fetches | indexes, covering-index, include, index-only-scan |
Use Covering Indexes to Avoid Table Lookups
Covering indexes include all columns needed by a query, enabling index-only scans that skip the table entirely.
Incorrect (index scan + heap fetch):
create index users_email_idx on users (email);
-- Must fetch name and created_at from table heap
select email, name, created_at from users where email = 'user@example.com';
Correct (index-only scan with INCLUDE):
-- Include non-searchable columns in the index
create index users_email_idx on users (email) include (name, created_at);
-- All columns served from index, no table access needed
select email, name, created_at from users where email = 'user@example.com';
Use INCLUDE for columns you SELECT but don't filter on:
-- Searching by status, but also need customer_id and total
create index orders_status_idx on orders (status) include (customer_id, total);
select status, customer_id, total from orders where status = 'shipped';
Reference: Index-Only Scans