Database Indexing Trade-offs

HardSQL · PostgreSQL

Problem

Can you describe the trade-offs between different database indexing strategies?

Use the supplied PostgreSQL benchmark data to compare each strategy quantitatively. Include strategies without qualifying benchmark runs so the result reflects both measured performance and missing evidence.

Output

One row per index strategy, ordered by overall cost score ascending, with unscored strategies last.
Columns: strategy_name, index_method, index_size_mb, benchmark_count, avg_read_latency_ms, avg_write_latency_ms, and tradeoff_score.
Round latency and score values to two decimal places. Use NULL for unavailable averages or scores.

Output details

Count only benchmark runs with workload read_heavy or mixed.
Calculate tradeoff_score as read latency plus 25% of write latency plus 2% of index size.
Treat missing write latency as 0 when calculating tradeoff_score, provided read latency is available.
Sort equal scores by strategy_name ascending.

Schema

index_strategies

Column	Type	Description
strategy_idPK	INT	Unique identifier for an indexing strategy
strategy_name	VARCHAR(100)	Name of the index strategy
index_method	VARCHAR(30)	PostgreSQL index access method
index_size_mb	DECIMAL(10,2)	Estimated storage consumed by the index
write_overhead_pct	DECIMAL(5,2)	Estimated percentage of write overhead
notes	VARCHAR(255)	Optional strategy notes

benchmark_runs

Column	Type	Description
run_idPK	INT	Unique benchmark run identifier
strategy_id	INT	Referenced indexing strategy
workload	VARCHAR(30)	Workload category used by the benchmark
read_latency_ms	DECIMAL(10,2)	Measured read latency in milliseconds
write_latency_ms	DECIMAL(10,2)	Measured write latency in milliseconds
rows_examined	INT	Number of rows examined during the run

Tablesindex_strategiesbenchmark_runs