earthdistance module在Postgresql 9.6.5上安装OSX El Capitan 10.11.6。 PG已安装，正常工作。我创建了extension，首先安装了cube：
rich=# CREATE EXTENSION earthdistance CASCADE;
NOTICE: installing required extension "cube"
CREATE EXTENSION
重启我的盒子。打开psql，选择正确的数据库，询问函数（\df）：
rich=# \df
List of functions
Schema | Name | Result data type | Argument data types | Type
--------+--------------------+------------------+------------------------------------------+--------
public | cube | cube | cube, double precision | normal
public | cube | cube | cube, double precision, double precision | normal
public | cube | cube | double precision | normal
public | cube | cube | double precision, double precision | normal
public | cube | cube | double precision[] | normal
public | cube | cube | double precision[], double precision[] | normal
public | cube_cmp | integer | cube, cube | normal
public | cube_contained | boolean | cube, cube | normal
public | cube_contains | boolean | cube, cube | normal
public | cube_coord | double precision | cube, integer | normal
public | cube_coord_llur | double precision | cube, integer | normal
public | cube_dim | integer | cube | normal
public | cube_distance | double precision | cube, cube | normal
public | cube_enlarge | cube | cube, double precision, integer | normal
public | cube_eq | boolean | cube, cube | normal
public | cube_ge | boolean | cube, cube | normal
public | cube_gt | boolean | cube, cube | normal
public | cube_in | cube | cstring | normal
public | cube_inter | cube | cube, cube | normal
public | cube_is_point | boolean | cube | normal
public | cube_le | boolean | cube, cube | normal
public | cube_ll_coord | double precision | cube, integer | normal
public | cube_lt | boolean | cube, cube | normal
public | cube_ne | boolean | cube, cube | normal
public | cube_out | cstring | cube | normal
public | cube_overlap | boolean | cube, cube | normal
public | cube_size | double precision | cube | normal
public | cube_subset | cube | cube, integer[] | normal
public | cube_union | cube | cube, cube | normal
public | cube_ur_coord | double precision | cube, integer | normal
public | distance_chebyshev | double precision | cube, cube | normal
public | distance_taxicab | double precision | cube, cube | normal
public | earth | double precision | | normal
public | earth_box | cube | earth, double precision | normal
public | earth_distance | double precision | earth, earth | normal
public | g_cube_compress | internal | internal | normal
public | g_cube_consistent | boolean | internal, cube, smallint, oid, internal | normal
public | g_cube_decompress | internal | internal | normal
public | g_cube_distance | double precision | internal, cube, smallint, oid, internal | normal
public | g_cube_penalty | internal | internal, internal, internal | normal
public | g_cube_picksplit | internal | internal, internal | normal
public | g_cube_same | internal | cube, cube, internal | normal
public | g_cube_union | cube | internal, internal | normal
public | gc_to_sec | double precision | double precision | normal
public | geo_distance | double precision | point, point | normal
public | latitude | double precision | earth | normal
public | ll_to_earth | earth | double precision, double precision | normal
public | longitude | double precision | earth | normal
public | sec_to_gc | double precision | double precision | normal
(49 rows)
所以似乎extension加载得很好。作为测试，我使用以下简单命令：
SELECT point(43.664828,-79.341620) <@> point(44.418390, -80.096013)
在psql我没有收到任何反馈。在Postico 1.3.2（PG客户端）中，我收到以下错误：
ERROR: operator does not exist: point <@> point
LINE 1: SELECT point(43.664828,-79.341620) <@> point(44.418390, -80....
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
根据反馈，似乎没有安装模块。我希望这可以正常工作，因为extension已正确安装，我正在使用earth_distance function的正确语法。我尝试过具有相同类型错误的其他查询，表明不识别运算符。
我做错了什么？
答案 0 :(得分：0)
解决。事实证明，您必须选择database的{{1}}才能应用于该特定extension。只需输入database就在应用程序级别内，因此psql显然对任何数据库都是盲目的。因此，请使用CREATE EXTENSION earthdistance CASCADE语法输入psql，然后应用psql <dbname>将其应用于您选择的数据库。