Installing pglogical: Find postgres include folder, add all include folders to C_INCLUDE_PATH

Question

I am trying to install the pglogical extension in my postgres database, which I installed on my macOS with homebrew. I am following instructions provided on the GCP blog as I am preparing to migrate my database to CloudSQl with Database Migration Service.

I am struggling to complete the following step of these steps, and could use some advice:

Find where Homebrew installed Postgres, find include folder, add all include folders to C_INCLUDE_PATH

My questions are:

• I found the include folder with pg_config --includedir
• But now, where is the pglogical C_INCLUDE_PATH variable? (I searched the pglogical repo and didn't find it) Or where do I create the C_INCLUDE_PATH variable?
• Am I to add all subdirectories of the include folder to the C_INCLUDE_PATH variable?

When I run make in the pglogical repo, I get the following:

sed 's/__PGLOGICAL_VERSION__/2.4.1/;s/__REQUIRES__//' /.../.../Documents/pglogical/pglogical.control.in > /.../.../Documents/pglogical/pglogical.control

Answer 1

pglogical is a third party postgreSQL extension provided by 2ndQuadrant and is not part of PostgreSQL. Some of it is written in C++, so must be compiled and built on the platform that it runs on. While many prebuilt tools and packages are available for macos via homebrew, pglogical doesn't seem to be one -- it was my search for this that led me to your question.

Options are:

• build, install, and enable a version for macos from source code
• install one of the packaged linux versions in a Docker container alongside postgres
• run against a version on your cloud provider (I am using AWS, looks like you're on GCP)

Building and installing on macos is pretty straightforward. In my case, I installed postgresql (14.1) using homebrew. Once complete:

• clone the pglogical extension from github
• ensure that you have XCode and command-line tools installed -- run brew doctor if you're not sure
• follow instructions for "unix-like platforms" here:
  • make PG_CONFIG=/usr/local/Cellar/postgresql/14.1_1/bin/pg_config
  • make PG_CONFIG=/usr/local/Cellar/postgresql/14.1_1/bin/pg_config install

Next, add the extension to shared_preload_libraries in postgres:

• cd /usr/local/var/postgres
• edit postgresql.conf
  • find the commented line shared_preload_libraries
  • add a line shared_preload_libraries = 'pglogical';
• restart postgres (with homebrew: brew services restart postgresql)

Finally, enable the extension in your local server:

• psql
  • CREATE EXTENSION pglogical which should respond with
  • CREATE EXTENSION

This all worked for me! Hope your luck is as good.