一个开发环境有多个网站，需要使用不同的session，解决方案很多。不过这次也高大上一把，用数据库存，方便以后扩展。

首先是数据库的部分

--drop table php_sessioncreate unlogged table php_session(    sess_id varchar(32) primary key,    modify_time timestamp with time zone not null,    sess_data varchar(3000) default '');create index concurrently idx_php_session_modify_time on php_session(modify_time);--set_session(id, data)create or replace function set_session(varchar, varchar) returns void as $set_session$    with upsert as (        update php_session        set modify_time = current_timestamp, sess_data = $2        where sess_id = $1        returning 1    )    insert into php_session (sess_id, modify_time, sess_data)    select $1, current_timestamp, $2    where not exists (        select 1 from upsert    );$set_session$ language sql;--get_session(id)create or replace function get_session(varchar) returns varchar as $get_session$    select sess_data from php_session where sess_id = $1$get_session$ language sql;--del_sessioncreate or replace function del_session(varchar) returns void as $del_session$    delete from php_session where sess_id = $1$del_session$ language sql;--gc_sessioncreate or replace function gc_session() returns void as $del_session$    delete from php_session where modify_time < current_timestamp - interval '30 days'$del_session$ language sql;

然后是PHP的部分

然后只要在session_start之前调用这个就可以了

至于SESSION_CONN，那是我定义的一个常量，表示一个指向session数据库的链接而已