On Wed, 9 Sep 2015 09:54:28 -0400 Igor Tandetnik <igor at tandetnik.org> wrote:
> On 9/9/2015 6:54 AM, Eduardo Morras wrote: > > Yes, the comparison operators work correctly and the b-tree binary > > search should give correct answers, the only tweak is in xCompare, > > that returns 0 when left(x) and rigth($value) expressions distance > > is lower than a threshold. > > A comparison like this would not generally be a proper collation. The > equivalence relation it induces is not transitive - it's possible to > have A == B and B == C but A != C (when A is "close enough" to B and > B is "close enough" to C, but A and C are just far enough from each > other). Yes, in first mail I noted that, but I don't think it's a problem because: a) xCompare(A,C) returns A<C or A>C (-1/+1), b) the query always return only one value, c) no ORDER BY in query, d) hashed data hash are far enough / disperse and expect no new additions. I'll compare collation vs virtual table with the tests cases, if fails or is slower I'll mark the collation branch as closed. Thanks > -- > Igor Tandetnik --- --- Eduardo Morras <emorrasg at yahoo.es>
