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nw-query-optimization SKILL.md skillA

nw-query-optimization from nwave-ai/nwave is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add nwave-ai/nwave/nw-query-optimization@git:20260320.d98f3cb

Pins git:20260320.d98f3cb in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: nwave-ai/nwave
Path: nWave/skills/nw-query-optimization/SKILL.md
Versions recorded: 3
Latest version: git:20260320.d98f3cb, committed Mar 20, 2026
First version recorded: Mar 17, 2026
Size: 5,330 bytes
Repository stars: 633
License: MIT

SQL and NoSQL query optimization techniques, indexing strategies, execution plan analysis, JOIN algorithms, cardinality estimation, and database-specific query patterns.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# Query Optimization

## Cost-Based Optimization

Modern relational DBs use cost-based optimizers (CBO): generate plan candidates -> estimate cost via statistics (row counts, distributions, selectivity) -> select lowest I/O/CPU/memory plan. Stale statistics lead to suboptimal plans.

### Execution Plan Analysis

Validate optimization with EXPLAIN before and after changes.

```sql
-- PostgreSQL (add ANALYZE for actual runtime stats)
EXPLAIN ANALYZE SELECT order_id, total FROM orders WHERE customer_id = 12345;
-- MySQL: EXPLAIN FORMAT=JSON ... | SQL Server: SET STATISTICS IO ON
```

Key indicators: **Seq Scan/Table Scan** = missing index | **Index Scan/Seek** = efficient | **Hash Join** = large equality joins | **Nested Loop** = small/indexed inner | **Merge Join** = pre-sorted inputs | **Sort** = watch disk spills

## Indexing Strategies

### B-Tree (Default)
Supports: equality, range, sorting, prefix matching | O(log n) lookup | General-purpose, all major DBs default

### Hash
Equality only | O(1) lookup | High-cardinality exact-match | No range/sorting/pattern support

### Covering Indexes
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add nwave-ai/nwave/nw-query-optimization@sha256:6738e287f7dbd0eb

The line at the top of this page pins the label git:20260320.d98f3cb, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

[![mdr](https://markdownregistry.com/badge/art_f4jc7qdmmr7mu5kw.svg)](https://markdownregistry.com/a/art_f4jc7qdmmr7mu5kw)

3 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 3 versions of this file, between Mar 17, 2026 and Mar 20, 2026, about one every day.

version	committed	commit	size	audit
git:20260320.d98f3cb latest	2026-03-20	d98f3cb	5,330 B	A	view · diff
git:20260318.e6a0e19	2026-03-18	e6a0e19	5,308 B	A	view · diff
git:20260317.1d16147	2026-03-17	1d16147	5,299 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (5330 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag

Source

GitHub

nwave-ai/nwave · 633 stars · license MIT · pushed 2026-11-07 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_f4jc7qdmmr7mu5kw
GET https://markdownregistry.com/api/v1/resolve?ref=nwave-ai/nwave/nw-query-optimization
GET https://markdownregistry.com/api/v1/blob/6738e287f7dbd0eb40ccb7ec5a076025a3a9c295b715dd6a0e1fb3386218a31a

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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