On 9/8/16 11:08 PM, Peter Geoghegan wrote:
> In principle, and assuming I haven't gotten something wrong, it ought
> to be possible to unambiguously identify a collation based on a
> matching UCA version (i.e. DUCET table), plus the collation tailorings
> matching exactly, even across ICU versions that happen to be based on
> the same UCA version (they only seem to put out a new UCA version
> about once a year [4]). It *might* be fine, practically speaking, to
> assume that a collation with a matching iso-code and UCA version is
> compatible forever and always across any ICU version. If not, it might
> instead be feasible to write a custom fingerprinter for collation
> tailorings that ran at initdb time.
The documentation [0] states that the collation version covers a broad
range of things. So I don't think these additional mechanisms you
describe are necessary.
[0]: http://userguide.icu-project.org/collation/architecture#TOC-Versioning
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
