\\c test
CREATE EXTENSION postgis;
CREATE EXTENSION postgis_topology;

CREATE TABLE t_user(uid int PRIMARY KEY,name varchar(20),location geometry);
CREATE INDEX t_user_location on t_user USING GIST(location);

## 创建一个自动名字生成函数：
create or replace function random_string(length integer) returns text as
$$
declare
chars text[] := '{0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}';
result text := '';
i integer := 0;
length2 integer := (select trunc(random() * length + 1));
begin
if length2 < 0 then
raise exception 'Given length cannot be less than 0';
end if;
for i in 1..length2 loop
result := result || chars[1+random()*(array_length(chars, 1)-1)];
end loop;
return result;
end;
$$ language plpgsql;

## 插入一千万条测试数据
insert into t_user select generate_series(1,10000000), random_string(20),st_setsrid(st_makepoint(150-random()*100, 90-random()*100), 4326);