Hello, one my customer reported a "out of memory" issue. After investigation he found a main problem in large query that uses a lot of union all queries. He wrote a self test:
do $$ declare i integer; str text=''; begin for i in 1..1000 loop str := str || 'union all select i,i,i from generate_series(1,50000) g(i) '; end loop; execute 'select 1,2,3 ' || str; end; $$ is it expected behave? Tested on PostgreSQL 9.1, 9.2, 9.3 It looks so all generated data are saved in memory only. Regards Pavel Stehule
