Re: Using quicksort for every external sort run

On Sat, Dec 12, 2015 at 5:28 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
> On Sat, Dec 12, 2015 at 12:10 AM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
>> I have a question about the terminology used in this patch. What is a
>> tuple proper? What is it in contradistinction to? I would think that
>> a tuple which is located in its own palloc'ed space is the "proper"
>> one, leaving a tuple allocated in the bulk memory pool to be
>> called...something else. I don't know what the
>> non-judgmental-sounding antonym of postpositive "proper" is.
>
> "Tuple proper" is a term that appears 5 times in tuplesort.c today. As
> it says at the top of that file:
>
> /*
> * The objects we actually sort are SortTuple structs. These contain
> * a pointer to the tuple proper (might be a MinimalTuple or IndexTuple),
> * which is a separate palloc chunk --- we assume it is just one chunk and
> * can be freed by a simple pfree(). SortTuples also contain the tuple's
> * first key column in Datum/nullflag format, and an index integer.

I see only three. In each case, "the tuple proper" could be replaced
by "the tuple itself" or "the actual tuple" without changing the
meaning, at least according to my understanding of the meaning. If
that's causing confusion, perhaps we should just change the existing
wording.

Anyway, I agree with Jeff that this terminology shouldn't creep into
function and structure member names.

I don't really like the term "memory pool" either. We're growing a
bunch of little special-purpose allocators all over the code base
because of palloc's somewhat dubious performance and memory usage
characteristics, but if any of those are referred to as memory pools
it has thus far escaped my notice.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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