On Fri, Feb 1, 2019 at 10:49:13AM +1300, Saul, Jean Paolo wrote:
> Hi Bruce,
>
> Thank you for that info. We will likely migrate our boolean indexes (and
> possibly all our low cardinality indexes) to hash after we move to PG11.
Uh, there is rarely value in creating boolean indexes because, for an
index to be useful, it should have high selectivity. What people often
do is to create _partial_ indexes on true, false, or NULL values that
are of high selectivity. Since there is only a single value in the
index, I guess a hash index would be better than btree, but I am not
sure.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
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