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我试图弄清楚如何连接到 postgres 数据库,运行查询,然后断开连接。

查看Postgrex,我使用

{:ok, pid} = Postgrex.start_link(hostname: "localhost", username: "postgres", password: "postgres", database: "postgres")

然后我使用执行我的查询

Postgrex.query!(pid, "SELECT user_id, text FROM comments", [])

但是,我该如何断开连接?

我想断开连接,因为我正在遍历 N 个数据库并在所有数据库上运行相同的查询。

我尝试退出进程,例如Process.exit(pid, :bye),但它也终止了产卵进程,因为它是从start_link/3. 我start/3Postgrex.

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1 回答 1

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由于pid返回的Postgrex.start_link是 a GenServer,您可以使用GenServer.stop/1

iex(1)> {:ok, pid} = Postgrex.start_link(hostname: "localhost", username: "postgres", password: "postgres", database: "postgres")
{:ok, #PID<0.277.0>}
iex(2)> GenServer.stop(pid)                                                                                                 
:ok
iex(3)> GenServer.stop(pid)
** (exit) no process: the process is not alive or there's no process currently associated with the given name, possibly because its application isn't started
    (stdlib) proc_lib.erl:797: :proc_lib.stop/3
于 2017-06-22T15:14:16.070 回答