On 5/12/24 05:55, Matthias van de Meent wrote:
> pg=# CREATE UNIQUE INDEX ON temporal_testing USING gist (id, valid_during);
> ERROR: access method "gist" does not support unique indexes
To me that error message seems correct. The programmer hasn't said anything
about the special
temporal behavior they are looking for.
But I showed that I had a GIST index that does have the indisunique
flag set, which shows that GIST does support indexes with unique
semantics.
That I can't use CREATE UNIQUE INDEX to create such an index doesn't
mean the feature doesn't exist, which is what the error message
implies.
True, the error message is not really telling the truth anymore. I do think most people who hit this
error are not thinking about temporal constraints at all though, and for non-temporal constraints it
is still true. It's also true for CREATE INDEX, since WITHOUT OVERLAPS is only available on the
*constraint*. So how about adding a hint, something like this?:
ERROR: access method "gist" does not support unique indexes
HINT: To create a unique constraint with non-overlap behavior, use ADD
CONSTRAINT ... WITHOUT OVERLAPS.
Yours,
--
Paul ~{:-)
p...@illuminatedcomputing.com
