On Wed, Aug 17, 2022 at 2:58 PM Bruce Momjian <bruce@momjian.us> wrote:
On Wed, Aug 17, 2022 at 12:41:03PM -0400, Jeff Janes wrote: > This was recently added to CREATE INDEX reference page: > > + The optional <literal>USING</literal> clause specifies an index > + type as described in <xref linkend="indexes-types"/>. If not > + specified, a default index type will be used based on the > + data types of the columns. > > But I think this is wrong, the default type is BTREE, it does not depend on the > data type. Or at least, I've never witnessed the claimed behavior. The claim > also conflicts with what is said at https://www.postgresql.org/docs/10/ > indexes-types.html
You are correct --- parser/gram.y has:
access_method_clause: USING name { $$ = $2; } | /*EMPTY*/ { $$ = DEFAULT_INDEX_TYPE; }