[ruby-on-rails] Can't find the 'libpq-fe.h header when trying to install pg gem

I am using the Ruby on Rails 3.1 pre version. I like to use PostgreSQL, but the problem is installing the pg gem. It gives me the following error:

$ gem install pg
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

        /home/u/.rvm/rubies/ruby-1.9.2-p0/bin/ruby extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/u/.rvm/rubies/ruby-1.9.2-p0/bin/ruby
    --with-pg
    --without-pg
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config


Gem files will remain installed in /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0 for inspection.
Results logged to /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0/ext/gem_make.out

How do I solve this problem?

I recently upgraded to Mac OS X v10.10 (Yosemite) and was having difficulty building the pg gem.

The error reported was the typical:

Using config values from /usr/local/bin/pg_config
checking for libpq-fe.h... *** extconf.rb failed ***

My solution was to gem uninstall pg and then bundle update pg to replace the gem with the latest. I did run brew update; brew upgrade after the Yosemite install to get the latest versions of packages I had installed previously.

On macOS (previously Mac OS X and OS X), use Homebrew to install the proper headers:

brew install postgresql

and then running

gem install pg

should work.

Alternatively, instead of installing the whole postgresql, you can brew install libpq and export the correct PATH and PKG_CONFIG_PATH as explained in the 'Caveats' section

I could solve this in another way. I didn't find the library on my system. Thus I installed it using an app from PostgreSQL main website. In my case (OS X) I found the file under /Library/PostgreSQL/9.1/include/ once the installation was over. You may also have the file somewhere else depending on your system if you already have PostgreSQL installed.

Thanks to this link on how to add an additional path for gem installation, I could point the gem to the lib with this command:

export CONFIGURE_ARGS="with-pg-include=/Library/PostgreSQL/9.1/include/"
gem install pg

After that, it works, because it now knows where to find the missing library. Just replace the path with the right location for your libpq-fe.h

On FreeBSD (9.1) the necessary package is /usr/ports/database/postgresql-server* which when installed will also install the required header file that makes the gem install of "pg" fail. This answer here helped me find the solution but the difference in package names required a bit of searching.

Hopefully this helps someone avoid a bit of head scratching when searching for the "-dev" package on a FreeBSD system!

On OS X and MacPorts the -devel package for PostgreSQL is not required any more. Installing the pg gem works as follows:

~ > sudo port install postgresql-devel
...
Error: postgresql-devel has been replaced by postgresql91; please install that port instead
~ > gem install pg -v '0.17.1' -- --with-pg-config=/opt/local/lib/postgresql95/bin/pg_config

See also this post.

For Mac OS X just install https://postgresapp.com/ and follow steps for command line section and ruby

sudo mkdir -p /etc/paths.d &&
echo /Applications/Postgres.app/Contents/Versions/latest/bin | sudo tee /etc/paths.d/postgresapp

Then

sudo ARCHFLAGS="-arch x86_64" gem install pg

I found this answer, and it was the only one that worked for me (Mac OS) - after researching for about two days:

$ sudo su

$ env ARCHFLAGS="-arch x86_64" gem install pg

Building native extensions.  This could take a while...
Successfully installed pg-0.11.0
1 gem installed
Installing ri documentation for pg-0.11.0...
Installing RDoc documentation for pg-0.11.0...

See Stack Overflow question Can't find the PostgreSQL client library (libpq).

I have tried all solutions but only works below command

pip install psycopg2-binary

Just for the record:

Ruby on Rails 4 application in OS X with PostgresApp (in this case 0.17.1 version needed - kind of an old project):

gem install pg -v '0.17.1' -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.3/bin/pg_config

I was having a similar problem, and this fixed it for me:

gem install do_postgres -- --with-pgsql-server-dir=/Applications/Postgres.app/Contents/MacOS --with-pgsql-server-include=/Applications/Postgres.app/Contents/MacOS/include/server

Source:

https://gist.github.com/oisin/6562181

I am running Postgres.app on a Mac and I had to

export PATH=$PATH:/Applications/Postgres.app/Contents/Versions/9.4/bin

first. Then

bundle install

worked for me.

I had this issue with Postgresql 9.6. I was able to fix it by doing:

brew upgrade [email protected]
brew link [email protected] --force
gem install pg

I finally solved this problem, but not using the previously described methods.

Using brew install postgresql, I find out that it had already been installed, but not linked.

1. Find out where PostgreSQL is installed, and delete it,

2. Then brew install postgresql again,

3. brew link postgresql

4. gem install pg

The right answer for Mac users with Postgres.app is to build against the libpq provided with that package. For example, with the 9.4 release (current as of this writing), all you need is:

export CONFIGURE_ARGS="with-pg-include=/Applications/Postgres.app/Contents/Versions/9.4/include"
gem install pg

This will keep your pg gem in sync with exactly the version of PostgreSQL you have installed. Installing something from Homebrew is a waste in this case.

For MacOS without installing PostgreSQL server:

brew install libpq
gem install pg -- --with-pg-config="/usr/local/Cellar/libpq/9.6.6/bin/pg_config"

On Ubuntu, install the "libpq-dev" to get rid of this issue.

sudo apt-get install libpq-dev

On OS X 10.9 (Mavericks), I brew-installed postgresql, and I then had to rvm reinstall my Ruby. I am happy now :)

I just had this on OSX running brew and [email protected].

My fix was this:

CONFIGURE_ARGS="with-pg-include=/usr/local/opt/[email protected]/include/" bundle install

Only uninstalling (sudo apt-get purge) libpq-dev and re-installing it worked for me.

In my case it was package postgresql-server-dev-8.4 (I am on Ubuntu 11.04 (Natty Narwhal), 64 bits).

Can't find the libpq-fe.h header

i had success on CentOS 7.0.1406 running the following commands:

~ % psql --version # => psql (PostgreSQL) 9.4.1
yum install libpqxx-devel
gem install pg -- --with-pg-config=/usr/pgsql-9.4/bin/pg_config

Alternatively, you can configure bundler to always install pg with these options (helpful for running bundler in deploy environments),

• bundle config build.pg --with-pg-config=/usr/pgsql-9.4/bin/pg_config

On CentOS,I installed libpq-dev package using below command

yum install postgresql-devel

Executing gem install pg returned the same error as "No pg_config... trying anyway. If building fails, please try again with --with-pg-config=/path/to/pg_config".

Installing the gem as below solved my problem

gem install pg -- --with-pg-config=/usr/pgsql-x.x/bin/pg_config

On Mac OS X run like this:

gem install pg -- --with-pg-config=***/path/to/pg_config***

***/path/to/pg_config*** is path to pg_config

I encountered the same error with postgres installed through asdf. The pg-config solutions didn't work for me. Instead I had to locate the postgres include folder which contains the file and run the command with the --with-pg-include flag

gem install pg -- --with-pg-include=/<path>/.asdf/installs/postgres/<version>/include

I had also tried doing gem install libpq-dev, but I received this error:

Can't find the 'libpq-fe.h header
*** extconf.rb failed ***

However I found that installing with sudo apt-get (which I try to avoid using with Ruby on Rails) worked, i.e.

sudo apt-get install libpq-dev
# or
apt-get install postgres-server-dev-{pg.version}
# for postgresql 9.4 on Ubuntu 14.04

then I was able to do

gem install pg

without issues.

The location of libpq-fe.h depends on where your PostgreSQL install is (which depends on how you installed it). Use locate (http://en.wikipedia.org/wiki/Locate_%28Unix%29) to find the libpq-fe.h file on your machine. If it exists, it will be in the include directory of your PostgreSQL install.

$ locate libpq-fe.h
/Library/PostgreSQL/9.1/include/libpq-fe.h

The bin directory, which contains pg_config, will be in the same directory as the include directory. As the error suggests, use the --with-pg-config option to install the gem:

$ gem install pg --with-pg-config="/Library/PostgreSQL/9.1/bin/pg_config"

Note that you may need to run updatedb if you have never used locate or if you haven't updated since installing PostgreSQL.

Under CentOS 6.5 (Squeeze) I created a file:

$ sudo touch /etc/profile.d/psql.sh

with content:

pathmunge /usr/pgsql-9.3/bin

Note here, you should set your PostgreSQL path with the pg_config file. You can find this with the command:

$ sudo find / -iname pg_config

Save the file:

$ sudo chmod +x /etc/profile.d/ruby.sh

and try to execute your command again.

Note: Anytime you change the Bash configuration - changing the profile.d configuration - you should reload Bash.

On Debian 7.0, 64-bit (Wheezy), just run:

sudo apt-get install libpq-dev

After you successfully installed libpq-dev, run:

bundle install

I had the same problem on Mac OS, but I installed the PostgreSQL gem easily by using the following in a terminal:

ARCHFLAGS="-arch x86_64" gem install pg

(I installed PostgreSQL first with brew install postgresql.)

Ubuntu 20.04.1 LTS, this seemed to work for me:

sudo apt-get install ruby ruby-dev libpqxx-dev libpq-fe-dev libpq-dev 
sudo gem install pg -- --with-pg-config=/usr/include/postgresql/pg_config --with-pg-include=/usr/include/postgresql/

My solution for Fedora 30:

sudo dnf install /usr/include/libpq-fe.h

I fixed the same error by doing a Ruby reinstall via rvm:

rvm reinstall 1.9.3

I had the same issue on Amazon Linux. I could find the header libpq-fe.h, but somehow it didn't work.

It came from the different versions of the packages that were installed through the different users on the machine. PostgreSQL 9.2 and PostgreSQL 9.3 were installed. So, make sure of your PostgreSQL version before including the libraries.

For me, the magic command line was:

sudo yum install postgresql93 postgresql93-server postgresql93-libs postgresql93-contrib postgresql93-devel

Source: An almost idiot's guide to install PostgreSQL 9.3, PostGIS 2.1 and pgRouting with Yum

Step 1) Make sure postgress is installed in your system ( If it's already installed and you can run postgress server on your machine move to step (2)

apt-get install postgresql postgresql-contrib (sol - fatal error: libpq-fe.h: No such file or directory)
sudo apt-get install ruby-dev (required to install postgress below)
sudo gem install pg
sudo service postgresql restart

Step 2) Some of the c++ files are trying to access libpq-fe.h directly and cant find. So we need to manually search every such file and replace libpq-fe.h with postgresql/libpq-fe.h

Command for searching all occurrences of libpq-fe.h in all dir and subdir is grep -rnw ./ -e 'libpq-fe.h'

3) Go to All the file listed by command run in step 2 and manually change libpq-fe.h with postgresql/libpq-fe.h.

A more general answer for any Debian-based distribution (which includes Ubuntu) is the following. First, install the apt-file package running as root:

apt-get install apt-file

This allows you to search for packages containing a file. Then, update its database using

apt-file update

(this can be run as normal user). Then, look for the missing header using:

apt-file search libpq-fe.h

On my machine, this gives:

libpq-dev: /usr/include/postgresql/libpq-fe.h
postgres-xc-server-dev: /usr/include/postgres-xc/server/gtm/libpq-fe.h

There you go !

For AltLinux the package postgresqlx.x-devel (in my case postgresql9.5-devel) must be installed:

apt-get install postgresql9.5-devel

For CentOS 6.4,

yum install postgresql-devel
gem install pg

worked well!

On Arch Linux you will need to install postgresql-libs:

sudo pacman -Syu postgresql-libs

On Fedora 32, I managed to solve this same issue by installing lipq5-devel specifically.

If you install postgresql from the official repository, you will have several versions that won't fix the problem, so it's really a matter of trying out which one it needs.

I solved this installing the 'postgresql-common' package. This package provides the pg_config binary which is most likely what you were missing.

On a Mac, I solved it using this code:

gem install pg -v '0.18.4' -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.4/bin/pg_config