Technologies/PostgreSQL/n_live_tup
PostgreSQLPostgreSQLMetric

n_live_tup

Live row estimate
Dimensions:None
Available on:DatadogDatadog (1)Native (1)PrometheusPrometheus (1)
Interface Metrics (3)
DatadogDatadog
Enabled with `relations`. The number of live rows on the toast table of a relation. This metric is tagged with db, schema, table.
Dimensions:None
Native
Estimated number of live rows
Dimensions:None
PrometheusPrometheus
Estimated number of live rows
Dimensions:None
Sources
postgresql.toast.live_rowsgithub.com
n_live_tupgithub.com
stat_user_tables_n_live_tupgithub.com

Technical Annotations (17)

Configuration Parameters (6)
autovacuum_vacuum_scale_factorrecommended: 0.01 for high-churn tables
Fraction of table size that triggers autovacuum (default 0.2)
autovacuum_analyze_scale_factorrecommended: 0.005
Fraction of table size that triggers auto-analyze
autovacuum_vacuum_cost_delayrecommended: 2
Delay between vacuum cost limit checks
autovacuum_max_workersrecommended: 5-6 for high-write workloads
Number of parallel autovacuum workers (default 3)
autovacuum_vacuum_thresholdrecommended: 50
minimum dead tuples before vacuum triggers; keep at default for most cases
autovacuum_vacuum_cost_limitrecommended: 1000
Higher I/O budget per cycle allows vacuum to complete faster (default 200)
CLI Commands (6)
VACUUM ANALYZE table_name;remediation
SELECT schemaname, relname AS table_name, n_live_tup AS live_tuples, n_dead_tup AS dead_tuples, ROUND(n_dead_tup::numeric / NULLIF(n_live_tup, 0) * 100, 2) AS dead_pct, last_autovacuum, last_autoanalyze, autovacuum_count, autoanalyze_count FROM pg_stat_user_tables ORDER BY n_dead_tup DESC LIMIT 20;diagnostic
ALTER TABLE events SET (autovacuum_vacuum_threshold = 1000, autovacuum_vacuum_scale_factor = 0.005, autovacuum_analyze_threshold = 500, autovacuum_analyze_scale_factor = 0.005, autovacuum_vacuum_cost_delay = 0, autovacuum_vacuum_cost_limit = 3000);remediation
SELECT schemaname, relname AS table_name, n_dead_tup AS dead_tuples, n_live_tup AS live_tuples, last_autovacuum, last_autoanalyze, CASE WHEN n_live_tup > 0 THEN round(100.0 * n_dead_tup / n_live_tup, 1) ELSE 0 END AS dead_tuple_ratio FROM pg_stat_user_tables WHERE n_dead_tup > 500 ORDER BY n_dead_tup DESC LIMIT 15;diagnostic
ALTER TABLE sim_events SET (autovacuum_vacuum_scale_factor = 0.02, autovacuum_vacuum_threshold = 500, autovacuum_vacuum_cost_delay = 2, autovacuum_vacuum_cost_limit = 1000);remediation
SELECT relname, reloptions FROM pg_class WHERE relname = 'sim_events';diagnostic
Technical References (5)
pg_stat_user_tablescomponentMVCCconceptdead tuplesconcepttable bloatconceptHOT updatesconcept
Related Insights (3)
High dead tuple ratio causes table bloat and slow querieswarning
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High dead tuple percentage causes query degradation and cache inefficiencywarning
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Autovacuum triggers too late on large tables causing bloat and query degradationwarning
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