Re: GiST limits on contrib/cube with dimension > 100?

Andrey Borodin <x4mmm(at)yandex-team(dot)ru> writes:
>> 9 июня 2019 г., в 23:05, Siarhei Siniak <siarheisiniak(at)yahoo(dot)com> написал(а):
>> I've been using cube extension recompiled with
>> #define MAX_DIM 256.
>> But with a version 11.3 I'm getting the following error:
>> failed to add item to index page in <index_name>

> So, you have changed source code (removing dim constraint) and get cryptic error after that. In some way this is expected...

Yeah. There is necessarily a limit on the size of index entries,
and it's getting exceeded.

> Nevertheless, we can improve AddTuple messages. But there is not such strict guidelines as with B-tree. Probably, tuples should not be bigger than half of usable page space.

I do not think "improve AddTuple messages" is going to be enough to fix
this. Daniel was correct that this is the same problem seen in

https://www.postgresql.org/message-id/flat/AM6PR06MB57318C9882C021879DD4101EA3100%40AM6PR06MB5731.eurprd06.prod.outlook.com

See my reply there. I think we should continue this discussion on that
thread, since it has seniority.

regards, tom lane