On 2018-03-23 15:12:43 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > On 2018-03-23 14:33:25 -0400, Tom Lane wrote: > >> + MemoryContextSetIdentifier(func_cxt, function->fn_signature); > >> > >> This would cost an extra char * field in struct MemoryContextData, > >> which is slightly annoying but it doesn't exactly seem like a killer. > >> Then the memory stats dump code would just need to know to print this > >> field if it isn't NULL. > > > That's not a bad idea. How about storing a Node* instead of a char*? > > Then we could have MemoryContextStats etc support digging out details > > for a few types, without having to generate strings at runtime. > > Well, in the cases I'm thinking of at the moment, there's no handy Node > to point at, just module-private structs like PLpgSQL_function.
Well, the cases Vladimir were concerned about seem less clear though. It'd be nice if we could just point to a CachedPlanSource and such. > So doing anything like that would add nonzero overhead to construct > something. I'm not that sure there aren't easy way to overcome those - couldn't we "just" make FmgrInfo etc be tagged types? The space overhead of that can't matter in comparison to the size of the relevant structs. > There's also the fact that we don't want MemoryContextStats doing > anything very complicated, because of the risk of failure and the > likelihood that any attempt to palloc would fail (if we're there > because we're up against OOM already). That's true. But I'm not sure there's a meaningful difference in risk here. Obviously you shouldn't try to print a node tree or something, but an if statement looking Greetings, Andres Freund
