Technologies/PostgreSQL/postgresql.sequential_scans
PostgreSQLPostgreSQLMetric

postgresql.sequential_scans

Sequential scans initiated
Dimensions:None
Available on:DatadogDatadog (1)Native (1)OpenTelemetryOpenTelemetry (1)PrometheusPrometheus (1)
Interface Metrics (4)
DatadogDatadog
Enabled with `relations`. The number of sequential scans initiated on this table. This metric is tagged with db, schema, table.
Dimensions:None
Native
last_seq_scan statistic from pg_stat_all_tables
Dimensions:None
OpenTelemetryOpenTelemetry
The number of sequential scans.
Dimensions:None
PrometheusPrometheus
Number of sequential scans initiated on this table
Dimensions:None
Sources
postgresql.seq_scansgithub.com
last_seq_scangithub.com
postgresql.sequential_scansgithub.com
stat_user_tables_seq_scangithub.com

Technical Annotations (37)

Configuration Parameters (2)
default_statistics_targetrecommended: 500
Increase for skewed columns to improve histogram depth and cardinality estimates
cpu_tuple_costrecommended: 0.01
Estimated cost to process one tuple; affects optimizer decisions on scan methods
CLI Commands (16)
EXPLAIN (ANALYZE) SELECT * FROM table WHERE column = 'value';diagnostic
CREATE INDEX ON table_name(column_name);remediation
explain (analyze, buffers) SELECT latitude, longitude, id FROM cities WHERE country_code = 'CA';diagnostic
\d citiesdiagnostic
CREATE INDEX CONCURRENTLY ON cities (country_code);remediation
ALTER TABLE your_table ALTER COLUMN status SET STATISTICS 500;remediation
CREATE INDEX idx_orders_status_created ON orders (status, created_at);remediation
EXPLAIN ANALYZE SELECT o.id, o.total, c.name FROM orders o JOIN customers c ON c.id = o.customer_id WHERE o.created_at > '2026-01-01' AND o.status = 'completed';diagnostic
EXPLAIN ANALYZE SELECT * FROM table_name WHERE column_name = 'value'diagnostic
EXPLAIN ANALYZE query_returning_large_datasetdiagnostic
CREATE INDEX idx_orders_customer ON orders(customer_id);remediation
SELECT relname AS table, seq_scan, seq_tup_read, idx_scan, seq_tup_read / NULLIF(seq_scan, 0) AS avg_seq_tup FROM pg_stat_user_tables WHERE seq_scan > 0 ORDER BY seq_tup_read DESC LIMIT 20;diagnostic
SELECT schemaname || '.' || relname AS table, seq_scan, idx_scan, n_live_tup, round(100.0 * seq_scan / NULLIF(seq_scan + idx_scan, 0), 2) AS seq_scan_pct FROM pg_stat_user_tables WHERE seq_scan > 1000 AND n_live_tup > 10000 ORDER BY seq_scan DESC;diagnostic
SELECT datname, stats_reset FROM pg_stat_database;diagnostic
SELECT relname, seq_scan, seq_tup_read / seq_scan AS tup_per_scan FROM pg_stat_user_tables WHERE seq_scan > 0;diagnostic
SELECT schemaname, relname AS table_name, seq_scan, idx_scan, n_tup_ins AS inserts, n_tup_upd AS updates, n_tup_del AS deletes, n_dead_tup AS dead_tuples, last_vacuum, last_autovacuum FROM pg_stat_user_tables ORDER BY n_dead_tup DESC;diagnostic
Technical References (19)
Seq ScanconceptIndex ScanconceptRows Removed by FilterconceptEXPLAINcomponentCONCURRENTLYconcepthistogramconceptselectivityconceptcardinality estimatesconceptBitmap Index Scancomponentpg_stat_statementscomponentsequential scanconceptshared bufferscomponentwork memorycomponentWHERE predicateconceptpg_stat_user_indexescomponentpg_stat_user_tablescomponentpg_stat_databasecomponentseq_scancomponentidx_scancomponent
Related Insights (10)
Sequential scan instead of index scan causes 10-20x slowdownwarning
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Insufficient column statistics cause poor selectivity estimateswarning
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Sequential scan reads excessive rows due to missing indexwarning
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Missing or ineffective indexes cause sequential scans on large tableswarning
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Sequential scans consume CPU resources during row extraction phaseinfo
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Missing indexes force sequential scans on small result setswarning
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Large result sets make sequential scans optimal despite proper indexinginfo
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Missing indexes on WHERE clause columns cause full table scanscritical
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High sequential scan count may indicate missing indexes requiring query optimizationwarning
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High sequential scan to index scan ratio indicates missing indexeswarning
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