安装后无法在mac上启用postgis_topology和postgis等postgis扩展

Question

我已经按照这里的描述安装了 postgres 和 postgis

brew install postgres
brew install postgis

createdb postgis_test
psql postgis_test

psql (9.6.2)
Type "help" for help.

postgis_test=# CREATE EXTENSION postgis;
ERROR:  could not open extension control file "/usr/local/share/postgresql/extension/postgis.control": No such file or directory
ERROR:  could not stat file "/usr/local/share/postgresql/extension/postgis--2.3.2.sql": No such file or directory
ERROR:  could not access file "$libdir/postgis-2.3": No such file or directory

可能是什么错误？以及如何解决？