Robert Haas <robertmh...@gmail.com> writes: > On Thu, Dec 1, 2011 at 10:48 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> I am thinking that the btree code, at least, would want to just >> unconditionally do >> >> colsortinfo->comparator(datum1, datum2, colsortinfo) >> >> so for an opclass that fails to supply the low-overhead comparator, >> it would insert into the "comparator" pointer a shim function that >> calls the opclass' old-style FCI-using comparator. (Anybody who >> complains about the added overhead would be told to get busy and >> supply a low-overhead comparator for their datatype...) But to do >> that, we have to have enough infrastructure here to cover all cases, >> so omitting collation or not having a place to stash an FmgrInfo >> won't do.
> I'm slightly worried about whether that'll be adding too much overhead > to the case where there is no non-FCI comparator. But it may be no > worse than what we're doing now. It should be the same or better. Right now, we are going through FunctionCall2Coll to reach the FCI-style comparator. The shim function would be more or less equivalent to that, and since it's quite special purpose I would hope we could shave a cycle or two. For instance, we could probably afford to set up a dedicated FunctionCallInfo struct associated with the SortSupportInfo struct, and not have to reinitialize one each time. regards, tom lane -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers