Tom Lane wrote:<br /><blockquote cite="mid:3159.1011804418@sss.pgh.pa.us" type="cite"><pre wrap="">Stephan Szabo <a
class="moz-txt-link-rfc2396E"href="mailto:sszabo@megazone23.bigpanda.com"><sszabo@megazone23.bigpanda.com></a>
writes:<br/></pre><blockquote type="cite"><pre wrap="">Wouldn't it make sense to prefer operators/functions earlier in
thesearch<br />path for resolving ambiguity. So if you had plus(int4, int4) in my<br />schema and plus(int8, int8) in
system,and they'd otherwise cause an<br />ambiguity failure for the query, use the plus(int4, int4) on mine. It<br
/>seemsnot too far from having the search path shadow later exact matches.<br /></pre></blockquote><pre wrap=""><br
/>Giventhe complexity of the resolution rules (cf.<br /><a class="moz-txt-link-freetext"
href="http://developer.postgresql.org/docs/postgres/typeconv.html">http://developer.postgresql.org/docs/postgres/typeconv.html</a>),<br
/>it'snot clear that we can determine exactly which "later" entry ought<br />to be blamed for causing a resolution
failure. I'd be interested to<br />hear Lockhart's opinion on this --- but my gut feeling is we don't<br />want to go
there. The resolution rules are already complicated enough,<br />and I think layering an additional mechanism like that
ontothem might<br />make the behavior totally unpredictable.<br /><br />Another problem is that this would probably
causeearlier namespace<br />entries to be over-preferred. For example, suppose that the system<br />namespace has
plus(int4,int4)and plus(int8,int8) and you choose to<br />define plus(int4,int8) locally. I believe you'd suddenly
findyours<br />being used for *any* cross-datatype addit
ion, including cases that<br />had nothing obvious to do with either int4 or int8 ...<br /></pre></blockquote> This is
agood example. The other option is to use name, arg1, arg2... as a hunt path for function call resolution. This
woulddepend on when datatype promotion is occuring (i.e. int4 to int8, int8 to int4, etc... )<br /><br /> Then you
couldjust be really hard and say that only exact and trivial conversion matches in user space will be used . <br
/><br/> There is no easy answer for this, but whatever rules are initiated need to be something that someone can step
throughto solve w/o a machine.<br /><br /> I do think you will ultimately need a search utility that provides 'which'
functionality. (Given my namespace, which function in what namespace is going to be called.)<br /><blockquote
cite="mid:3159.1011804418@sss.pgh.pa.us"type="cite"><pre wrap=""><br /><br /> regards, tom lane<br /><br
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