On 2020-03-28 14:49:31 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > On 2020-03-27 19:57:12 -0400, Tom Lane wrote: > >> That being the case, I'd think a better design principle is "make your > >> new code look like the code around it", which would tend to weigh against > >> introducing StringInfo uses into pgbench when there's none there now and > >> a bunch of PQExpBuffer instead. So I can't help thinking the advice > >> you're being given here is suspect. > > > I don't agree with this. This is a "fresh" usage of StringInfo. That's > > different to adding one new printed line among others built with > > pqexpbuffer. If we continue adding large numbers of new uses of both > > pieces of infrastructure, we're just making things more confusing. > > Why? I'm not aware of any intention to deprecate/remove PQExpBuffer, > and I doubt it'd be a good thing to try. It does some things that > StringInfo won't, notably cope with OOM without crashing.
- code using it cannot easily be shared between frontend/backend (no memory context integration etc) - most code does *not* want to deal with the potential for OOM without erroring out - it's naming is even more confusing than StringInfo - it introduces dependencies to libpq even when not needed - both stringinfo and pqexpbuffer are performance relevant in some uses, needing to optimize both is wasted effort - we shouldn't expose everyone to both APIs except where needed - it's stuff one has to learn
