On Thu, Mar 12, 2015 at 6:23 PM, Andreas Karlsson <andr...@proxel.se> wrote: > Fixed.
Did you intend to attach a patch here? >> I think you should talk about the new thing first (just after the >> extant, first sentence "Integer data types use Numeric..."). Refer to >> where 128-bit integers are used and how, and only then the other stuff >> (exceptions). After that, put the PolyNumAggState struct definition >> and basic functions. Then int2_accum() and so on. > > > Good idea! Do you think the rewritten comment is clear enough, or do I need > to go into more detail? > > /* > * Integer data types use Numeric accumulators to share code and avoid risk > * of overflow. To speed up aggregation 128-bit integer accumulators are > * used instead where sum(X) or sum(X*X) fit into 128-bits, and there is > * platform support. > * > * For int2 and int4 inputs sum(X) will fit into a 64-bit accumulator, hence > * we use faster special-purpose accumulator routines for SUM and AVG of > * these datatypes. > */ > > #ifdef HAVE_INT128 > typedef struct Int128AggState Not quite. Refer to the 128-bit integer accumulators as "special-purpose accumulator routines" instead. Then, in the case of the extant 64-bit accumulators, refer to them by the shorthand "integer accumulators". Otherwise it's the wrong way around. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
