Installing the PostgreSQL Server

Apt Package Manager (Debian and Ubuntu)

Ubuntu 20.04

Instructions based on the Postgresql wiki

echo # Setup the postgres repository
sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'

echo # Install the postgres repository certificates
sudo apt install curl ca-certificates gnupg
curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -

echo # Install postgres
sudo apt update
sudo apt install postgresql-10 postgresql-contrib-10

Setting up the PostgreSQL Server

Changes to PostgreSQL Configuration Files

After installing the PostgreSQL server, a system user named "postgres" should have automatically been created.

In your Linux shell, change/switch to this user:

sudo su - postgres

Changes to pg_hba.conf File

Next, edit the PostgreSQL pg_hba.conf configuration file using a tool like vi or vim. The location differs between Linux flavors, e.g.:

• Debian/Ubuntu: /etc/postgresql/10/main/pg_hba.conf

So, in Ubuntu 20.04, for example, open it up with your preferred text editor:

vim /etc/postgresql/10/main/pg_hba.conf

Towards the end of the file, add (or modify) the following lines of text to the section starting with a line something like "# IPv4 local connections:":

# IPv4 local connections:
host    all             all         samehost                md5

Next, make sure entries under "IPv6 local connections" are disabled by adding the '#' character to beginning of this line:

# IPv6 local connections:
#host    all             all             ::1/128                md5

Save the changes and quit your editor.

Changes to postgresql.conf File

Finally, set the "max_prepared_transactions" property in the main PostgreSQL config file named postgresql.conf. The file's location differs between Linux flavors, e.g.:

• Debian/Ubuntu: /etc/postgresql/10/main/postgresql.conf

So, in Ubuntu 20.04, for example, open it up with your favorite text editor

vim /etc/postgresql/10/main/postgresql.conf

then make the following changes to that file:

max_prepared_transactions = 64

The max_prepared_transactions property might be commented out with the '#' character. If you see the '#' character at the beginning of this line, remove it.

Restarting PostgreSQL 10 database server: main The PostgreSQL server failed to start. Please check the log output ... FATAL: could not create shared memory segment: Invalid argument 
...
failed!

Save your changes and quit.

Log out of the 'postgres' account (use the shell 'exit' command to return to your normal linux account) and restart your PostgreSQL service:

exit
sudo systemctl restart postgresql

Set up datatype 'casts'

Now we need to create some datatype casts that CollectionSpace uses. While logged in as the postgres user, enter the psql shell:

sudo su - postgres
psql -U postgres -d template1

then enter the following commands into the psql shell:

CREATE FUNCTION pg_catalog.text(integer) RETURNS text STRICT IMMUTABLE LANGUAGE SQL AS 'SELECT textin(int4out($1));';
CREATE CAST (integer AS text) WITH FUNCTION pg_catalog.text(integer) AS IMPLICIT;
COMMENT ON FUNCTION pg_catalog.text(integer) IS 'convert integer to text';
CREATE FUNCTION pg_catalog.text(bigint) RETURNS text STRICT IMMUTABLE LANGUAGE SQL AS 'SELECT textin(int8out($1));';
CREATE CAST (bigint AS text) WITH FUNCTION pg_catalog.text(bigint) AS IMPLICIT;
COMMENT ON FUNCTION pg_catalog.text(bigint) IS 'convert bigint to text';

Remain in the psql shell and continue to the next section.

Create the 'csadmin' User

At psql's command prompt (ending in #), switch to the postgres database from the template1 database by entering the following (starting with a backslash character as shown):

\c postgres

In response, you should see a message similar to this:  You are now connected to database "postgres" as user "postgres".

 Enter the following command to create a csadmin user/role with appropriate privileges.  (Be sure to substitute a password of your choosing for replacemewithyourpassword below:

CREATE ROLE csadmin LOGIN PASSWORD 'replacemewithyourpassword' SUPERUSER INHERIT NOCREATEDB NOCREATEROLE NOREPLICATION;

In response, you should see a message similar to this: CREATE ROLE 

Quit the psql program by typing \q (or press ctrl+d).

Logout of the 'postgres' Linux account (use 'exit' command returns you to your normal linux account) and then restart the PostgreSQL server:

exit
sudo systemctl restart postgresql

Verify that you are able to connect to the PostgreSQL server using the csadmin account username and password you just added:

psql -U csadmin -h localhost -d postgres

If successful, you should be in the psql shell and see something like this:

psql (10.18 (Ubuntu 10.18-1.pgdg20.04+1))
SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, bits: 256, compression: off)
Type "help" for help.

postgres=# 

If you think you've encountered an error, send an email to the CollectionSpace "Talk" list at talk@collectionspace.org.  Include any error messages you've seen and give a detailed description of what steps you've already performed.

Next, exit the psql shell by typing \q (or press ctrl+d).

You're finished with the PostgreSQL setup. 

Database Tuning

Tuning takes place in postgresql.conf - the location differ among OS' flavours. Some examples are:

• Debian/Ubuntu: /etc/postgresql/10/main/postgresql.conf

For example, for Debian/Ubuntu:

vim /etc/postgresql/10/main/postgresql.conf

shared_buffers = 512MB

sysctl kernel.shmmax=650000000

You need to register the final value of shmmax:

Open /etc/sysctl.conf

vim /etc/sysctl.conf

kernel.shmmax = 650000000

Do this by running (and printing stats in megabytes):

free -m

This will give you an output like so:

free -m
             total       used       free     shared    buffers     cached
Mem:          4096       3302        793          0       253        1226
-/+ buffers/cache:       1822       2273
Swap:          511        216        295

find your effective cache_size by adding the number under buffers and cached. In the above example:
253+1226=1479

To this number you add the shared_buffers value .. so we get a total of:
1479+512=1991 ~ 2GB

again edit postgres conf

vim /etc/postgresql/10/main/postgresql.conf

and set effective cache size to the value you found in the previous steps.

effective_cache_size = 2GB

Also set the following values:

work_mem = 16MB                         # min 64kB
maintenance_work_mem = 32MB             # min 1MB
random_page_cost = 2.0

restart for changes to take effect

Debian/Ubuntu:

sudo systemctl restart postgresql

vim /etc/postgresql/10/main/pg_hba.conf

host      nuxeo      reader     samehost      md5

host 	nuxeo 	reader 	169.229.0.0/16 	md5

listen_addresses = '*' # what IP address(es) to listen on;