Dead Tuples without updates/deletes

Question

Is it possible? I have a table with fast growing dead tuples, but I can\'t see any update or delete to the table during the day, just inserts and selects. Autovacuum runs ea

Answer 1

A failed attempt to insert data may cause dead tuples. Example:

create table test(id serial primary key, str text);

insert into test (str) values ('abc');

select pg_stat_get_dead_tuples('test'::regclass);

 pg_stat_get_dead_tuples 
-------------------------
                       0
(1 row)

insert into test values (1, 'def');

ERROR:  duplicate key value violates unique constraint "test_pkey"
DETAIL:  Key (id)=(1) already exists.

select pg_stat_get_dead_tuples('test'::regclass);

 pg_stat_get_dead_tuples 
-------------------------
                       1
(1 row)

This also applies to the inserts aborted due to rollback.