Rails pg gem，安装pg时出错答案

【问题标题】：Rails pg gem, an error occurred while installing pgRails pg gem，安装pg时出错
【发布时间】：2014-01-12 10:45:54
【问题描述】：

我正在尝试将我的 rails 应用程序导入 Heroku，但在尝试安装 pg gem 时遇到了问题。我被告知将我的 Gemfile 中的“gem 'sqlite3'”行替换为以下内容：

group :development, :test do
  gem 'sqlite3'
end
group :production do
  gem 'pg'
  gem 'rails_stdout_logging' 
end

然后执行捆绑安装。我收到此错误消息：

...
Using coffee-rails (3.2.2) 
Using jquery-rails (3.0.4) 
Installing pg (0.17.1) with native extensions 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
    /usr/local/rvm/rubies/ruby-1.9.3-p392/bin/ruby extconf.rb 
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... yes
checking for PQconnectionUsedPassword()... yes
checking for PQisthreadsafe()... yes
checking for PQprepare()... yes
checking for PQexecParams()... yes
checking for PQescapeString()... yes
checking for PQescapeStringConn()... yes
checking for PQescapeLiteral()... yes
checking for PQescapeIdentifier()... yes
checking for PQgetCancel()... yes
checking for lo_create()... yes
checking for pg_encoding_to_char()... yes
checking for pg_char_to_encoding()... yes
checking for PQsetClientEncoding()... yes
checking for PQlibVersion()... yes
checking for PQping()... yes
checking for PQsetSingleRowMode()... no
checking for rb_encdb_alias()... yes
checking for rb_enc_alias()... yes
checking for rb_thread_call_without_gvl()... yes
checking for rb_thread_call_with_gvl()... yes
checking for rb_thread_fd_select()... yes
checking for rb_w32_wrap_io_handle()... no
checking for PGRES_COPY_BOTH in libpq-fe.h... no
checking for PGRES_SINGLE_TUPLE in libpq-fe.h... no
checking for PG_DIAG_TABLE_NAME in libpq-fe.h... no
checking for struct pgNotify.extra in libpq-fe.h... yes
checking for unistd.h... yes
checking for ruby/st.h... yes
creating extconf.h
creating Makefile
make
compiling gvl_wrappers.c
compiling pg.c
pg.c: In function ‘Init_pg_ext’:
pg.c:375: error: ‘PQPING_OK’ undeclared (first use in this function)
pg.c:375: error: (Each undeclared identifier is reported only once
pg.c:375: error: for each function it appears in.)
pg.c:377: error: ‘PQPING_REJECT’ undeclared (first use in this function)
pg.c:379: error: ‘PQPING_NO_RESPONSE’ undeclared (first use in this function)
pg.c:381: error: ‘PQPING_NO_ATTEMPT’ undeclared (first use in this function)
make: *** [pg.o] Error 1
Gem files will remain installed in /usr/local/rvm/gems/ruby-1.9.3-p392/gems/pg-0.17.1 for inspection.
Results logged to /usr/local/rvm/gems/ruby-1.9.3-p392/gems/pg-0.17.1/ext/gem_make.out
An error occurred while installing pg (0.17.1), and Bundler cannot continue.
Make sure that `gem install pg -v '0.17.1'` succeeds before bundling.

所以，我尝试执行 gem install pg -v '0.17.1'。我收到此错误消息：

Building native extensions.  This could take a while...
ERROR:  Error installing pg:
ERROR: Failed to build gem native extension.
/usr/local/rvm/rubies/ruby-1.9.3-p392/bin/ruby extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... yes
checking for PQconnectionUsedPassword()... yes
checking for PQisthreadsafe()... yes
checking for PQprepare()... yes
checking for PQexecParams()... yes
checking for PQescapeString()... yes
checking for PQescapeStringConn()... yes
checking for PQescapeLiteral()... yes
checking for PQescapeIdentifier()... yes
checking for PQgetCancel()... yes
checking for lo_create()... yes
checking for pg_encoding_to_char()... yes
checking for pg_char_to_encoding()... yes
checking for PQsetClientEncoding()... yes
checking for PQlibVersion()... yes
checking for PQping()... yes
checking for PQsetSingleRowMode()... no
checking for rb_encdb_alias()... yes
checking for rb_enc_alias()... yes
checking for rb_thread_call_without_gvl()... yes
checking for rb_thread_call_with_gvl()... yes
checking for rb_thread_fd_select()... yes
checking for rb_w32_wrap_io_handle()... no
checking for PGRES_COPY_BOTH in libpq-fe.h... no
checking for PGRES_SINGLE_TUPLE in libpq-fe.h... no
checking for PG_DIAG_TABLE_NAME in libpq-fe.h... no
checking for struct pgNotify.extra in libpq-fe.h... yes
checking for unistd.h... yes
checking for ruby/st.h... yes
creating extconf.h
creating Makefile
make
compiling gvl_wrappers.c
compiling pg.c
pg.c: In function ‘Init_pg_ext’:
pg.c:375: error: ‘PQPING_OK’ undeclared (first use in this function)
pg.c:375: error: (Each undeclared identifier is reported only once
pg.c:375: error: for each function it appears in.)
pg.c:377: error: ‘PQPING_REJECT’ undeclared (first use in this function)
pg.c:379: error: ‘PQPING_NO_RESPONSE’ undeclared (first use in this function)
pg.c:381: error: ‘PQPING_NO_ATTEMPT’ undeclared (first use in this function)
make: *** [pg.o] Error 1

我已经阅读了这些帖子并尝试了那里给出的解决方案，但它们都不起作用：

我使用的是 Mac OS X 10.8.5，如果您想知道的话

【问题讨论】：

标签： ruby-on-rails gem pg

【解决方案1】：

在控制台上运行以下命令...

sudo apt-get install libpq-dev


gem install pg

愉快的编码...

【讨论】：

【解决方案2】：

我猜你的系统中没有安装 postgres。您可以通过 homebrew/macports 安装 postgresql 或禁用 production gems 的安装：

bundle install --without production

【讨论】：

【解决方案3】：

问题在于您的系统上缺少 PostgreSQL 客户端。
在终端上运行这些命令

sudo apt-get install postgresql-client libpq5 libpq-dev

现在将此 gem 添加到您的 Gemfile 中

gem 'pg'

然后运行这个

bundle install

【讨论】：