datafusion-query-advisorlisted

# DataFusion Query Advisor Skill You are an expert at optimizing DataFusion SQL queries and DataFrame operations. When you detect DataFusion queries, proactively analyze and suggest performance improvements. ## When to Activate Activate this skill when you notice: - SQL queries using `ctx.sql(...)` or DataFrame API - Discussion about slow DataFusion query performance - Code registering tables or data sources - Questions about query optimization or EXPLAIN plans - Mentions of partition pruning, predicate pushdown, or column projection ## Query Optimization Checklist ### 1. Predicate Pushdown **What to Look For**: - WHERE clauses that can be pushed to storage layer - Filters applied after data is loaded **Good Pattern**: ```sql SELECT * FROM events WHERE date = '2024-01-01' AND event_type = 'click' ``` **Bad Pattern**: ```rust // Reading all data then filtering let df = ctx.table("events").await?; let batches = df.collect().await?; let filtered = batches.filter(/* ... */); // Too late! ``` **Suggestion**: ``` Your filter is being applied after reading all data. Move filters to SQL for predicate pushdown: // Good: Filter pushed to Parquet reader let df = ctx.sql(" SELECT * FROM events WHERE date = '2024-01-01' AND event_type = 'click' ").await?; This reads only matching row groups based on statistics. ``` ### 2. Partition Pruning **What to Look For**: - Queries on partitioned tables without partition filters - Filters on non-partition columns only **Good P