sql_Retrieve_Cluster_Queries
Extract SQL queries and performance metrics from Teradata clusters to identify optimization patterns, analyze query structures, and detect performance issues for database tuning.
Instructions
RETRIEVE ACTUAL SQL QUERIES FROM SPECIFIC CLUSTERS FOR PATTERN ANALYSIS
This tool extracts the actual SQL query text and performance metrics from selected clusters, enabling detailed pattern analysis and specific optimization recommendations. Essential for moving from cluster-level analysis to actual query optimization.
DETAILED ANALYSIS CAPABILITIES:
SQL Pattern Recognition: Analyze actual query structures, joins, predicates, and functions
Performance Correlation: Connect query patterns to specific performance characteristics
Optimization Identification: Identify common anti-patterns, missing indexes, inefficient joins
Code Quality Assessment: Evaluate query construction, complexity, and best practices
Workload Understanding: See actual business logic and data access patterns
QUERY SELECTION STRATEGIES:
By CPU Impact: Sort by 'ampcputime' to focus on highest CPU consumers
By I/O Volume: Sort by 'logicalio' to find scan-intensive queries
By Skew Problems: Sort by 'cpuskw' or 'ioskw' for distribution issues
By Complexity: Sort by 'numsteps' for complex execution plans
By Response Time: Sort by 'response_secs' for user experience impact
AVAILABLE METRICS FOR SORTING:
ampcputime: Total CPU seconds (primary optimization target)
logicalio: Total logical I/O operations (scan indicator)
cpuskw: CPU skew ratio (distribution problems)
ioskw: I/O skew ratio (hot spot indicators)
pji: Physical-to-Logical I/O ratio (compute intensity)
uii: Unit I/O Intensity (I/O efficiency)
numsteps: Query execution plan steps (complexity)
response_secs: Wall-clock execution time (user impact)
delaytime: Time spent in queue (concurrency issues)
AUTOMATIC PERFORMANCE CATEGORIZATION: Each query is categorized using configurable thresholds (from sql_opt_config.yml):
CPU Categories: VERY_HIGH_CPU (>config.very_high), HIGH_CPU (>config.high), MEDIUM_CPU (>10s), LOW_CPU
CPU Skew: SEVERE_CPU_SKEW (>config.severe), HIGH_CPU_SKEW (>config.high), MODERATE_CPU_SKEW (>config.moderate), NORMAL
I/O Skew: SEVERE_IO_SKEW (>config.severe), HIGH_IO_SKEW (>config.high), MODERATE_IO_SKEW (>config.moderate), NORMAL
Use thresholds set in config file for, CPU - high, very_high, Skew moderate, high, severe
TYPICAL OPTIMIZATION WORKFLOW:
Start with clusters identified from sql_Analyze_Cluster_Stats
Retrieve top queries by impact metric (usually 'ampcputime')
Analyze SQL patterns for common issues:
Missing WHERE clauses or inefficient predicates
Cartesian products or missing JOIN conditions
Inefficient GROUP BY or ORDER BY operations
Suboptimal table access patterns
Missing or outdated statistics
Develop specific optimization recommendations
QUERY LIMIT STRATEGY:
Use the query limit set in config file for pattern recognition and analysis, unless user specifies a different limit
OUTPUT INCLUDES:
Complete SQL query text for each query
All performance metrics, user, application, and workload context, cluster membership and rankings
Performance categories for quick filtering
Input Schema
Name | Required | Description | Default |
---|---|---|---|
cluster_ids | Yes | ||
limit_per_cluster | No | ||
metric | No | ampcputime |