> ...with each operation generally being allowed to use as much memory as this value specifies before it starts to
writedata into temporary files.
So, doesn't explain the 7452-byte files. Unless an operation can use a temporary file as an addendum to work_mem,
insteadof spilling the RAM contents to disk as is my understanding.
> So, if it's doing lots of joins, there may be lots of bits of temporary data which together add up to more than
work_mem.
If it's doing lots of joins, each will get work_mem--there is no "adding up" among operations using work_mem.
> You expect the smallest temporary file to be 128MB? I.e., if the memory used exceeds work_mem all of it gets put
intothe temp file at that point? Versus only the amount of data that exceeds work_mem getting pushed out to the
temporaryfile. The overflow only design seems much more reasonable - why write to disk that which fits, and already
exists,in memory.
Well, I don't know of an algorithm which can effectively sort 128MB + 7KB of data using 128MB of RAM and a 7KB file.
Samefor many of the other operations which use work_mem, so yes, I expected spill over to start with 128MB file and
growit as needed. If I'm wrong and there are operations which can effectively use temp files as adjunct, then that
wouldbe the answer to my question. Does anybody know for sure that this is the case?
