gist in exclude constraint in postgres

Question

I created table using exclude constraint.but i do not know the use of gist in exclude constraint?Why we specify the gist keyword in exclude constraint?.Any specify reason for this.

CREATE TABLE Employee_age_Details(
name varchar(50),
age integer,
EXCLUDE USING gist
(age WITH <>));

ok.but any specify reason for using gist in exclude constraint?.is it index? — Ram
– Ram, Commented Oct 25, 2019 at 9:15
thank you.so performances also improve for this column.am i correct? — Ram
– Ram, Commented Oct 25, 2019 at 9:18
@a_horse_with_no_name It actually does the opposite. The given EXCLUDE forces all employees to have the same age, not different. — jjanes
– jjanes, Commented Oct 25, 2019 at 15:22
@a_horse_with_no_name While GiST indexes offer the most flexibility, other ones do work with EXCLUDE. For example, you could do USING hash (age with =). — jjanes
– jjanes, Commented Oct 25, 2019 at 15:32

jjanes · Accepted Answer · 2019-10-25 15:28:56Z

3

The default index type, Btree, does not offer support for the '<>' operator. The GiST index type (under btree_gist) does. You must use an index type which supports the operator.

If you changed the constraint operator to '=', then you could omit the "gist". But in that case you should just use a unique constraint, as it does the same thing better.

answered Oct 25, 2019 at 15:28

jjanes

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