2015-03-10 22:53 GMT+01:00 Jim Nasby <jim.na...@bluetreble.com>: > On 2/22/15 5:19 AM, Pavel Stehule wrote: > >> >> >> 2015-02-22 3:00 GMT+01:00 Petr Jelinek <p...@2ndquadrant.com >> <mailto:p...@2ndquadrant.com>>: >> >> On 28/01/15 08:15, Pavel Stehule wrote: >> >> >> >> 2015-01-28 0:01 GMT+01:00 Jim Nasby <jim.na...@bluetreble.com >> <mailto:jim.na...@bluetreble.com> >> <mailto:Jim.Nasby@bluetreble.__com >> <mailto:jim.na...@bluetreble.com>>>: >> >> On 1/27/15 4:36 AM, Pavel Stehule wrote: >> >> >> It is only partially identical - I would to use cache for >> array_offset, but it is not necessary for array_offsets >> .. >> depends how we would to modify current API to support >> externally >> cached data. >> >> >> Externally cached data? >> >> >> Some from these functions has own caches for minimize access to >> typcache >> (array_map, array_cmp is example). And in first case, I am trying >> to >> push these information from fn_extra, in second case I don't do >> it, >> because I don't expect a repeated call (and I am expecting so >> type cache >> will be enough). >> >> >> You actually do caching via fn_extra in both case and I think that's >> the correct way, and yes that part can be moved common function. >> >> I also see that the documentation does not say what is returned by >> array_offset if nothing is found (it's documented in code but not in >> sgml). >> >> >> rebased + fixed docs >> > > I don't think we need both array_offset and array_offset_start; can't both > SQL functions just call one C function? >
There is a rule about unique mapping C functions to SQL space - and I don't think so this rule is bad. > > It might be worth combining the array and non-array versions of this, by > having a _common function that accepts a boolean and then just run one or > the other of the while loops. Most of the code seems to be shared between > the two versions. > > What is this comment supposed to mean? There is no 'width_array'... > It is typo (I am sorry) - should be width_bucket(, array) http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=e80252d424278abf65b624669c8e6b3fe8587cac The code is similar, but it expect large **sorted** input. array_offset works on unsorted (alphabetical unsorted) data sets - like days of week .. > > * Biggest difference against width_array is unsorted input array. > > I've attached my doc changes, both alone and with the code. > > -- > Jim Nasby, Data Architect, Blue Treble Consulting > Data in Trouble? Get it in Treble! http://BlueTreble.com >
