On 8th of February, Peter Eisentraut committed patch:
Per-column collation support This adds collation support for columns and domains, a COLLATE clause to override it per expression, and B-tree index support. Peter Eisentraut reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch Branch ------ master
Continue reading Waiting for 9.1 – Per-column collation support