#	exclusive	inclusive	rows x	rows	loops	node
1.	0.042	0.660	↑ 1.0	1	1	→ Aggregate (cost=23.64..23.65 rows=1 width=8) (actual time=0.659..0.660 rows=1 loops=1)
2.	0.096	0.618	↑ 1.0	122	1	→ Hash Join (cost=18.67..23.33 rows=122 width=0) (actual time=0.474..0.618 rows=122 loops=1) Hash Cond: (pg_index.indrelid = pg_class.oid)
3.	0.079	0.079	↑ 1.0	122	1	→ Seq Scan on pg_index (cost=0.00..4.34 rows=122 width=4) (actual time=0.016..0.079 rows=122 loops=1) Filter: indisunique Rows Removed by Filter: 12
4.	0.240	0.443	↓ 1.0	342	1	→ Hash (cost=14.41..14.41 rows=341 width=4) (actual time=0.443..0.443 rows=342 loops=1) Buckets: 1024 Batches: 1 Memory Usage: 21kB
5.	0.203	0.203	↓ 1.0	342	1	→ Seq Scan on pg_class (cost=0.00..14.41 rows=341 width=4) (actual time=0.007..0.203 rows=342 loops=1)

	Query Text: SELECT count(*)
	FROM pg_class, pg_index
	WHERE oid = indrelid AND indisunique;
	Aggregate  (cost=23.64..23.65 rows=1 width=8) (actual time=0.659..0.660 rows=1 loops=1)
	  ->  Hash Join  (cost=18.67..23.33 rows=122 width=0) (actual time=0.474..0.618 rows=122 loops=1)
	        Hash Cond: (pg_index.indrelid = pg_class.oid)
	        ->  Seq Scan on pg_index  (cost=0.00..4.34 rows=122 width=4) (actual time=0.016..0.079 rows=122 loops=1)
	              Filter: indisunique
	              Rows Removed by Filter: 12
	        ->  Hash  (cost=14.41..14.41 rows=341 width=4) (actual time=0.443..0.443 rows=342 loops=1)
	              Buckets: 1024  Batches: 1  Memory Usage: 21kB
	              ->  Seq Scan on pg_class  (cost=0.00..14.41 rows=341 width=4) (actual time=0.007..0.203 rows=342 loops=1)

Per node type stats

node type	count	sum of times	% of query
Aggregate	1	0.042 ms	6.4 %
Hash	1	0.240 ms	36.4 %
Hash Join	1	0.096 ms	14.5 %
Seq Scan	2	0.282 ms	42.7 %

Per table stats

Table name	Scan count	Total time	% of query
scan type	count	sum of times	% of table
pg_class	1	0.203 ms	30.8 %
Seq Scan	1	0.203 ms	100.0 %
pg_index	1	0.079 ms	12.0 %
Seq Scan	1	0.079 ms	100.0 %

explain.depesz.com

PostgreSQL's explain analyze made readable

Result: aTKq : Optimization for: plan #FSB

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Per node type stats

Per table stats