Calculating Optimal memory for disk based sort is based only on minimizing IO.
A previous post stated we can merge as many subfiles as we want in a single pass,
this is not accurate, as we want to eliminate disk seeks also in the merge phase,
also the merging should be done by reading blocks of dat
IMHO (as a wanbe pgsql hacker) it is more important to mark tasks as
suitable for beginners, if they do not require in depth knowledge of
the pgsql codebase, and not
according to how easy they are in other terms.
for example If a task requires a significant amount of new non trivial
code which has
