Hi.

In one recent research, i fails to understand of how PostgreSQL work with physical memory when executing a queries. Perhaps, someone had experience in the analysis of this issue.
All tests was acted on PostgreSQL 12, Debian 10.
In first, we have an execution plan of query. The execution plan contains HASH JOIN operations (search by query (regex "hash.+join ") shows us about 82 hash joins).
In FIRST...