Re: Building infrastructure for B-Tree deduplication that recognizes when opclass equality is also equivalence

Anastasia Lubennikova <a.lubennikova@postgrespro.ru> wrote:

> The patch implementing new opclass option is attached.
>
> It adds new attribute pg_opclass.opcisbitwise, which is set to true if opclass
> equality is the same as binary equality.
> By default it is true.

I think the default value should be false and we should only set it to true
for individual opclasses which do meet the bitwise equality requirement. Also
extension authors should explicitly state that their data types are bitwise
equal. Otherwise the existing opclasses, when created via pg_dump ->
pg_restore, can be used by the system incorrectly.

> It is set to false for numeric and float4, float8.

Are you sure about these?

--
Antonin Houska
Web: https://www.cybertec-postgresql.com