I did a test as you mentioned and in postgresql version 11 I didn't observe any change in memory consumption while the query is executed. With version 14, running the same query, it is possible to observe a considerable increase in memory usage during execution. Could it be a bug in postgresql's memory management?
WITH DADOS as ( select 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL ... ) select * from dados;
When executing a query containing WITH and more than a thousand UNION ALL, PostgreSQL version 14 or higher uses all server memory until it enters recovery mode. In tests with version 11, this behavior does not occur. shouldn't he respect the work_mem?
*I know I should refactor, but what caught my attention was the fact that a query uses the entire resource without restriction, which does not occur in version 11.4, I did a test in version 15, which also occurs.
Has anything related to memory usage in this sense been changed?
