PostgreSQL never stored strxfrm() output in indexes, but did at one time use it to build indexes (that is, strxfrm() was used to build values when sorting). How

PostgreSQL never stored strxfrm() output in indexes, but did at one time use it to build indexes (that is, strxfrm() was used to build values when sorting). However, it would be nice to be able to store strxfrm() output on disk, in indexes, which as you say leaves the implementation sensitive to changes in the transformation algorithm, and not just the underlying behavior defined by a collation. Fortunately, it is possible to do this safely with ICU, which explicitly decouples implementation issues from behavioral issues. Maybe this will happen at some point in the future. For now, abbreviated keys are only used for sorting to build an index, and not in any subsequent index scan. If you want much faster text sorting back, using "abbreviated keys", you can use ICU collations in Postgres 10. With the C standard library, strxfrm() was disabled when it was found to be buggy within glibc [1]. [1] https://wiki.postgresql.org/wiki/Abbreviated_keys_glibc_issue https://wiki.postgresql.org/wiki/Abbreviated_keys_glibc_issu...