我正在探索使用 Elixir 快速导入混合类型（CSV、JSON）的 Postgres 数据。作为 Elixir 的新手，我正在遵循 youtube 视频“使用 Elixir 和 Postgrex 快速导入和导出 - Elixir Hex 包展示”（https://www.youtube.com/watch?v=YQyKRXCtq4s）中给出的示例。基本的混合应用程序一直工作到引入 Poolboy 为止，即 Postgrex 使用单个连接成功地将记录加载到数据库中。
当我尝试遵循 Poolboy 配置并通过运行对其进行测试时
FastIoWithPostgrex.import("./data_with_ids.txt")
在 iex 或命令行中，我收到以下错误，我无法确定原因（已删除用户名和密码）：
** (UndefinedFunctionError) function DBConnection.Poolboy.child_spec/1 is
undefined (module DBConnection.Poolboy is not available)
DBConnection.Poolboy.child_spec({Postgrex.Protocol, [types:
Postgrex.DefaultTypes, name: :pg, pool: DBConnection.Poolboy, pool_size: 4,
hostname: "localhost", port: 9000, username: "XXXX", password:
"XXXX", database: "ASDDataAnalytics-DEV"]})
(db_connection) lib/db_connection.ex:383: DBConnection.start_link/2
(fast_io_with_postgrex) lib/fast_io_with_postgrex.ex:8:
FastIoWithPostgrex.import/1
我在 Windows 10 上运行它，通过本地 SSH 隧道连接到 PostgreSQL 10.x 服务器。这是 lib/fast_io_with_postgrex.ex 文件：
defmodule FastIoWithPostgrex do
@moduledoc """
Documentation for FastIoWithPostgrex.
"""
def import(filepath) do
{:ok, pid} = Postgrex.start_link(name: :pg,
pool: DBConnection.Poolboy,
pool_size: 4,
hostname: "localhost",
port: 9000,
username: "XXXX", password: "XXXX", database: "ASDDataAnalytics-DEV")
File.stream!(filepath)
|> Stream.map(fn line ->
[id_str, word] = line |> String.trim |> String.split("\t", trim: true, parts: 2)
{id, ""} = Integer.parse(id_str)
[id, word]
end)
|> Stream.chunk_every(10_000, 10_000, [])
|> Task.async_stream(fn word_rows ->
Enum.each(word_rows, fn word_sql_params ->
Postgrex.transaction(:pg, fn conn ->
IO.inspect Postgrex.query!(conn, "INSERT INTO asdda_dataload.words (id, word) VALUES ($1, $2)", word_sql_params)
# IO.inspect Postgrex.query!(pid, "INSERT INTO asdda_dataload.words (id, word) VALUES ($1, $2)", word_sql_params)
end , pool: DBConnection.Poolboy, pool_timeout: :infinity, timeout: :infinity)
end)
end, timeout: :infinity)
|> Stream.run
end # def import(file)
end
这是 mix.exs 文件：
defmodule FastIoWithPostgrex.MixProject do
use Mix.Project
def project do
[
app: :fast_io_with_postgrex,
version: "0.1.0",
elixir: "~> 1.7",
start_permanent: Mix.env() == :prod,
deps: deps()
]
end
# Run "mix help compile.app" to learn about applications.
def application do
[
extra_applications: [:logger, :poolboy, :connection]
]
end
# Run "mix help deps" to learn about dependencies.
defp deps do
[
# {:dep_from_hexpm, "~> 0.3.0"},
# {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git",
tag: "0.1.0"},
{:postgrex, "~>0.14.1"},
{:poolboy, "~>1.5.1"}
]
end
end
这是 config/config.exs 文件：
# This file is responsible for configuring your application
# and its dependencies with the aid of the Mix.Config module.
use Mix.Config
config :fast_io_with_postgrex, :postgrex,
database: "ASDDataAnalytics-DEV",
username: "XXXX",
password: "XXXX",
name: :pg,
pool: DBConnection.Poolboy,
pool_size: 4
# This configuration is loaded before any dependency and is restricted
# to this project. If another project depends on this project, this
# file won't be loaded nor affect the parent project. For this reason,
# if you want to provide default values for your application for
# 3rd-party users, it should be done in your "mix.exs" file.
# You can configure your application as:
#
# config :fast_io_with_postgrex, key: :value
#
# and access this configuration in your application as:
#
# Application.get_env(:fast_io_with_postgrex, :key)
#
# You can also configure a 3rd-party app:
#
# config :logger, level: :info
#
# It is also possible to import configuration files, relative to this
# directory. For example, you can emulate configuration per environment
# by uncommenting the line below and defining dev.exs, test.exs and such.
# Configuration from the imported file will override the ones defined
# here (which is why it is important to import them last).
#
# import_config "#{Mix.env()}.exs"
任何有关查找此错误原因的帮助将不胜感激！