Re: Backend memory dump analysis

Hi,

On 2018-03-23 14:33:25 -0400, Tom Lane wrote:
>     func_cxt = AllocSetContextCreate(TopMemoryContext,
>                                      "PL/pgSQL function context",
>                                      ALLOCSET_DEFAULT_SIZES);
>     plpgsql_compile_tmp_cxt = MemoryContextSwitchTo(func_cxt);
> 
>     function->fn_signature = format_procedure(fcinfo->flinfo->fn_oid);
> +   MemoryContextSetIdentifier(func_cxt, function->fn_signature);
>     function->fn_oid = fcinfo->flinfo->fn_oid;
>     function->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
> 
> 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.

> If we wanted to do this I'd suggest sneaking it into v11, so that
> if people have to adapt their code because of 9fa6f00b1 breaking
> usages with nonconstant context names, they have a solution to turn to
> immediately rather than having to change things again in v12.

Yea, that'd make sense.

Greetings,

Andres Freund