diagnostic-performance-n1

Diagnostic: N+1 Query Pattern Detection

You detect potential N+1 query patterns in custom WordPress PHP code using a two-pass approach — grep for pattern candidates, then AI contextual analysis to confirm patterns and extract actual variable names for targeted rewrite suggestions.

Overview

The N+1 query anti-pattern occurs when a database query is executed inside a loop, causing one query per iteration instead of a single batch query. The problem scales linearly with content volume:

• 10 posts in a loop = 10 separate database queries instead of 1
• 100 posts in a loop = 100 queries instead of 1
• 1,000 posts in a loop = 1,000 queries instead of 1

This is one of the leading causes of WordPress performance degradation. A page that takes 200ms with 10 posts may take 2,000ms with 100 posts — not because the page design changed, but because loop queries multiply with data volume.

Why custom code only: Users cannot fix N+1 patterns in WooCommerce, Yoast SEO, Elementor, or other third-party plugins — those are maintained by their vendors. Flagging patterns in code users cannot modify wastes diagnostic time and creates alert fatigue. This skill scans custom themes and custom plugins only.

Prerequisites

Before scanning, you need:

• LOCAL_PATH — path to the locally synced site files (from sites.json via /connect or /diagnose)
• No WP-CLI required — this skill performs purely static analysis on synced PHP files

Self-gate: If LOCAL_PATH is not set, does not exist, or contains no PHP files, return the skip finding immediately and stop.

# Check LOCAL_PATH exists and contains PHP files
if [ -z "$LOCAL_PATH" ] || [ ! -d "$LOCAL_PATH" ]; then
  # Return PERF-N1-SKIP finding
  exit 0
fi

PHP_FILE_COUNT=$(find "$LOCAL_PATH/wp-content/themes" "$LOCAL_PATH/wp-content/plugins" \
  -name "*.php" 2>/dev/null | wc -l | tr -d '[:space:]')

if [ "$PHP_FILE_COUNT" -eq 0 ]; then
  # Return PERF-N1-SKIP finding
  exit 0
fi

Section 1: Target Directories