1294  Query Performance Analyzer

Interactive Tool for Database Query Analysis and Optimization

animation
databases
query-optimization
performance

1294.1 Query Performance Analyzer Tool

This interactive tool helps you understand and compare query performance across different database systems commonly used in IoT applications. Analyze execution plans, identify bottlenecks, and receive optimization recommendations.

NoteTool Overview

Compare query performance across five popular IoT databases:

  • InfluxDB: Purpose-built time-series database
  • TimescaleDB: PostgreSQL extension for time-series
  • MongoDB: Document-oriented NoSQL database
  • PostgreSQL: Relational database with JSON support
  • Cassandra: Wide-column distributed database
TipHow to Use This Tool
  1. Select your database type and query pattern
  2. Configure data characteristics (table size, indexing)
  3. Write or select a sample query
  4. Click “Analyze Query” to see execution plan
  5. Review performance metrics and cost breakdown
  6. Enable comparison mode for side-by-side database analysis
  7. Apply recommended optimizations

1294.2 Understanding Query Performance

1294.2.1 Query Types in IoT Databases

Different query patterns have vastly different performance characteristics across database systems:

Query Type Description Best For
Time-Range Aggregation Aggregate metrics over time windows Dashboard analytics
Latest Value Most recent reading per device Real-time status
Anomaly Detection Find outliers and threshold violations Alerting systems
Join with Metadata Combine time-series with device info Reporting
Time-Series Rollup Downsample to lower granularity Long-term trends

1294.2.2 Database Selection Guide

TipChoose InfluxDB when:
  • Primary workload is time-series metrics
  • High write throughput is critical (>100K points/sec)
  • You need built-in retention policies
  • Simple aggregations dominate queries
NoteChoose TimescaleDB when:
  • You need full SQL compatibility
  • Complex queries with joins are required
  • Team already knows PostgreSQL
  • Both relational and time-series data coexist
WarningChoose Cassandra when:
  • Linear horizontal scaling is required
  • Write-heavy workloads dominate (>90% writes)
  • High availability across data centers is critical
  • Query patterns are well-defined and limited

1294.3 Execution Plan Components

1294.3.1 Common Operations

Operation Description Performance Impact
Index Seek Direct lookup using B-tree index Very Fast (O(log n))
Index Range Scan Scan portion of sorted index Fast
Sequential Scan Full table scan Slow (O(n))
Hash Join Join using in-memory hash table Medium (memory intensive)
Nested Loop Join via nested iteration Slow for large tables
Aggregate Compute SUM/AVG/COUNT/etc. Depends on row count
Sort Order results Memory intensive

1294.3.2 Cost Components

  • CPU Cost: Computation for filtering, aggregation, sorting, joins
  • I/O Cost: Disk reads for data retrieval and index access
  • Memory Cost: Working memory for sorts, hash tables, aggregations
  • Network Cost: Data transfer between nodes (distributed systems)

1294.4 Optimization Strategies

1294.4.1 Index Optimization

-- Time-based index for range queries
CREATE INDEX idx_sensors_time ON sensors (timestamp DESC);

-- Composite index for filtered queries
CREATE INDEX idx_sensors_device_time
  ON sensors (device_id, timestamp DESC);

-- BRIN index for time-ordered data (PostgreSQL)
CREATE INDEX idx_sensors_brin ON sensors USING BRIN (timestamp);

-- Partial index for hot data
CREATE INDEX idx_sensors_recent ON sensors (timestamp DESC)
  WHERE timestamp > NOW() - INTERVAL '7 days';

1294.4.2 Query Optimization Patterns

-- Efficient: Use index on timestamp
SELECT * FROM sensors
WHERE timestamp > NOW() - INTERVAL '1 hour'
  AND device_id = 'sensor-001'
ORDER BY timestamp DESC
LIMIT 100;

-- Inefficient: Function on indexed column
SELECT * FROM sensors
WHERE DATE(timestamp) = '2024-01-01';  -- Cannot use index

-- Better: Range comparison
SELECT * FROM sensors
WHERE timestamp >= '2024-01-01'
  AND timestamp < '2024-01-02';

1294.5 What’s Next


This query analyzer demonstrates key OJS/D3.js concepts:

  1. Performance Modeling: Estimates based on database characteristics, query patterns, and data size
  2. Execution Plan Visualization: SVG-based operation flow with cost indicators
  3. Cost Breakdown: CPU, I/O, Memory, and Network component analysis
  4. Comparison Mode: Side-by-side database evaluation
  5. Throughput Calculator: QPS estimation with concurrency modeling
  6. Index Recommendations: Context-aware SQL/NoSQL optimization suggestions
  7. IEEE Color Palette: Consistent styling with book design system

The tool uses simplified performance models that capture relative differences between databases for educational purposes.