Jeff Davis <pgsql(at)j-davis(dot)com> writes:
> Attached is a small patch to $SUBJECT.
> In master, only single-byte characters are allowed as an escape. Of
> course, with the patch it must still be a single character, but it may
> be multi-byte.
I'm concerned about the performance cost of this patch. Have you done
any measurements about what kind of overhead you are putting on the
inner loop of similar_escape?
At the very least, please don't call GetDatabaseEncoding() over again
every single time through the inner loop. More generally, why do we
need to use pg_encoding_verifymb? The input data is presumably validly
encoded. ISTM the significantly cheaper pg_mblen() would be more
appropriate.
regards, tom lane