Rails error Database pg [duplicate] - ruby-on-rails

Question

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?

Answer 1

It looks like in Ubuntu that header is part of the libpq-dev package (at least in the following Ubuntu versions:
11.04 (Natty Narwhal), 10.04 (Lucid Lynx), 11.10 (Oneiric Ocelot), 12.04 (Precise Pangolin), 14.04 (Trusty Tahr) and 18.04 (Bionic Beaver)):
...
/usr/include/postgresql/libpq-fe.h
...
So try installing libpq-dev or its equivalent for your OS:
For Ubuntu/Debian systems: sudo apt-get install libpq-dev
On Red Hat Linux (RHEL) systems: yum install postgresql-devel
For Mac Homebrew: brew install postgresql
For Mac MacPorts PostgreSQL: gem install pg -- --with-pg-config=/opt/local/lib/postgresql[version number]/bin/pg_config
For OpenSuse: zypper in postgresql-devel
For ArchLinux: pacman -S postgresql-libs

Answer 2

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

Answer 3

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.

Answer 4

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

Answer 5

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

Answer 6

For CentOS 6.4,
yum install postgresql-devel
gem install pg
worked well!

Answer 7

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

Answer 8

It is only issue of missing libpq-fe.h
On ubuntu we just need to run:
sudo apt-get install libpq-dev
Above command will install a NEW package libpq-dev and after that you can again execute bundle install to resume your bundle installation.

Answer 9

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

Answer 10

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

Answer 11

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"

Answer 12

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.

Answer 13

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

Answer 14

My solution for Fedora 30:
sudo dnf install /usr/include/libpq-fe.h

Answer 15

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 !

Answer 16

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

Answer 17

On Fedora 32, I managed to solve this same issue by installing libpq5-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.

Answer 18

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.)

Answer 19

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).

Answer 20

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.

Answer 21

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

Answer 22

I had this issue with Postgresql 9.6. I was able to fix it by doing:
brew upgrade postgresql#9.6
brew link postgresql#9.6 --force
gem install pg

Answer 23

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.

Answer 24

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

Answer 25

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

Answer 26

On Ubuntu 20.04, I already had libpq5:amd64 version 13.2-1.pgdg20.04+1. Now when I tried to install libpq-dev from apt repository, I was receiving
The following packages have unmet dependencies:
libpq-dev : Depends: libpq5 (= 12.6-0ubuntu0.20.04.1) but 13.2-1.pgdg20.04+1 is to be installed
I grabbed the deb from http://ftp.us.debian.org/debian/pool/main/p/postgresql-13/libpq-dev_13.2-1_amd64.deb and did the following:
mkdir -p /tmp/libpq-dev
dpkg-deb -R libpq-dev_13.2-1_amd64.deb /tmp/libpq-dev
sed -i 's|= 13.2-1|= 13.2-1.pgdg20.04+1|' /tmp/libpq-dev/DEBIAN/control
dpkg-deb -b /tmp/libpq-dev /tmp/libpq-dev-new.deb
sudo dpkg -i /tmp/libpq-dev-new.deb
I have been using the gem happily after that. No additional installs or anything.

Answer 27

For alpine, please use below to fix the error
apk add --no-cache postgresql-dev

Answer 28

On debian bullseye, none of the existing answers solved the issue for me.
In case it helps someone with the same configuration as mine:
Use PostgreSQL's apt repository: https://wiki.postgresql.org/wiki/Apt
sudo apt-get update && sudo apt-get dist-upgrade (upgrade PostgreSQL from v13 to v14)
sudo apt-get install libpq-dev
gem install pg or bundle install

Answer 29

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!

Answer 30

On Debian 7.0, 64-bit (Wheezy), just run:
sudo apt-get install libpq-dev
After you successfully installed libpq-dev, run:
bundle install