Strabon: A Java repository from AI-team-UoA

Installing Strabon on Linux ( Ubuntu 20.04 )

Prerequisites

Install maven 3.6.3:

 wget https://archive.apache.org/dist/maven/maven-3/3.6.3/binaries/apache-maven-3.6.3-bin.tar.gz \
 && tar -xvf apache-maven-3.6.3-bin.tar.gz \
 && mv apache-maven-3.6.3 /opt/
 
 M2_HOME='/opt/apache-maven-3.6.3'
 PATH="$M2_HOME/bin:$PATH"
 export PATH

Install Java 8:

 sudo apt-get install openjdk-8-jdk openjdk-8-jre

Installing PostgreSQL and PostGIS

Install PostgreSQL 12 & PostGIS 3.0 :

 sudo apt install postgresql-12 postgresql-12-postgis-3

Provide a password for default user (postgres)

 sudo -u postgres psql -c "ALTER USER postgres WITH PASSWORD 'postgres';"

Creating a spatially enabled database for PostgreSQL

Log in as superuser
```
 sudo su - postgres
```
Create the spatial database that will be used as a template:
```
 createdb -E UTF8 -T template0 template_postgis
```

Create a PostGIS extention:

 psql -d template_postgis -c "CREATE EXTENSION postgis"

Allow users to alter spatial tables

    psql -d template_postgis -c "GRANT ALL ON geometry_columns TO PUBLIC;"
    psql -d template_postgis -c "GRANT ALL ON geography_columns TO PUBLIC;"
    psql -d template_postgis -c "GRANT ALL ON spatial_ref_sys TO PUBLIC;"

Perform garbage collection

    psql -d template_postgis -c "VACUUM FULL;"
    psql -d template_postgis -c "VACUUM FREEZE;"

Allows non-superusers the ability to create from this template

    psql -d postgres -c "UPDATE pg_database SET datistemplate='true' WHERE datname='template_postgis';"
    psql -d postgres -c "UPDATE pg_database SET datallowconn='false' WHERE datname='template_postgis';"

Create a spatially-enabled database named endpoint

    createdb endpoint -T template_postgis

Compiling Strabon

Clone the source code of Strabon from this repository.
Change to the directory that Strabon source code resides in:
```
 cd Strabon
```
Build Strabon:
```
mvn clean pacakge
```

Tuning PostgreSQL

The default settings of Postgres are rather conservative. As a result, parameter tuning is neccessary for speeding up Postgres, therefore Strabon. If you are using Strabon to compare its performance against your implementation of stSPARQL/GeoSPARQL, you are strongly encouraged to contact us using the Strabon Users mailing list for assistance on tuning Postgres. You can follow the instructions below for tuning a Postgres server running on an Ubuntu machine that is dedicated to PostgreSQL and Strabon. ( The following settings work on Unix-based systems. Windows do not allow some of the options listed bellow)

Append the following text at the end of postgresql.conf, Uncomment the appropriate lines :

 ### RAM
 ## 4 GB of RAM
 #shared_buffers       =  3GB
 #effective_cache_size =  3GB
 #maintenance_work_mem =  1GB
 #work_mem             =  2GB
 ## 8 GB of RAM
 #shared_buffers       =  5GB
 #effective_cache_size =  6GB
 #maintenance_work_mem =  2GB
 #work_mem             =  5GB
 ## 16 GB of RAM
 #shared_buffers       = 10GB
 #effective_cache_size = 14GB
 #maintenance_work_mem =  4GB
 #work_mem             = 10GB
 ## 24 GB of RAM
 #shared_buffers       = 16GB
 #effective_cache_size = 22GB
 #maintenance_work_mem =  6GB
 #work_mem             = 15GB
 ## 48 GB of RAM
 #shared_buffers       = 32GB
 #effective_cache_size = 46GB
 #maintenance_work_mem =  8GB
 #work_mem             = 30GB
 ## 64 GB of RAM
 # contact us to find out!
 ### HD
 ## RAID with ordinary 7.200 disks
 #random_page_cost = 3.5 #3.0-3.5
 ## High-End NAS/SAN
 #random_page_cost = 2 #1.5-2.5
 ## Amazon EBS/Heroku
 #random_page_cost = 1.3 #1.1-2.0
 ## SSD array
 #random_page_cost = 2.0 #1.5-2.5
 ### Planner options
 # Increase the following values in order to avoid using the GEQO planner.
 # Small values (<8) reduce planning time but may produce inferior query plans
 #
 geqo_threshold = 15 # keep this value larger that the following two parameters
 from_collapse_limit = 14
 join_collapse_limit = 14
 ### Misc
 default_statistics_target    = 10000
 constraint_exclusion         = on
 checkpoint_completion_target = 0.9
 wal_buffers                  = 32MB
 ### Connections
 max_connections              = 10

Append the following lines at the end of /etc/sysctl.conf, Uncomment the appropriate lines:

## 4 GB of RAM
#kernel.shmmax = 3758096384
#kernel.shmall = 3758096384
#kernel.shmmni = 4096
## 8 GB of RAM
#kernel.shmmax = 5905580032
#kernel.shmall = 5905580032
#kernel.shmmni = 4096
## 16 GB of RAM
#kernel.shmmax = 11274289152
#kernel.shmall = 11274289152
#kernel.shmmni = 4096
## 24 GB of RAM
#kernel.shmmax = 17716740096
#kernel.shmall = 17716740096
#kernel.shmmni = 4096
## 48 GB of RAM
#kernel.shmmax = 35433480192
#kernel.shmall = 35433480192
#kernel.shmmni = 4224
## 64 GB of RAM
# contact us to find out!

Apply all changes by executing :

 sudo sysctl -p
 sudo /etc/init.d/postgresql restart

Prepare for the next run by issuing the command, where db is the name of the Postgres database that Strabon will use:
```
 sudo -u postgres psql -c 'VACUUM ANALYZE;' db
```

Installing Strabon on Windows

First download PostgreSQL database from here. (Version 12.13)
Then install the .exe file
When you will be asked for a password for the user postgres, enter postgres
For anything else, keep the defaults
Then, in the Stack builder select "PostgreSQL 12.13 on port 5432"
Then check the Spatial Extension PostGIS 3.0 for PostgreSQL 12.13
Then, in the PostGIS installation, check the option "Create spatial database"
Then enter the password for the user postgres (it must be postgres from the step 3)
Then for the Database Name enter "template_postgis"
Then press Yes, Close and Finish
Now you have PostgreSQL and PostGIS installed
Now open pgadmin IV (it was installed with postgreSQL)
Create a new database with the name "endpoint" and in the definition select as template the "template_postgis"

Installing a Strabon Endpoint

Tomcat

Install Tomcat compatible with Java 8 (eg. 9.0.68).
Add a new user in the tomcat-users.xml file. This file is usually located in the folder $TOMCAT_HOME/conf. Note that this user should be a member of the manager group. For example, add the following line inside a tomcat-users element to the file tomcat-users.conf and restart tomcat:
```
 <user username="endpoint" password="endpoint" roles="manager-gui"/>
```

Initial install

Create a directory where you want to place the sources of the Strabon on your machine, and cd into that directory, e.g.:
```
 mkdir Strabon
 cd Strabon
```
Clone the source code from this repository.
The source code of the endpoint is located at the folder Strabon of the source code tree that you just cloned, so cd into that directory, e.g.:
```
cd Strabon
```
Edit the endpoint/WebContent/WEB-INF/connection.properties file and define the PostgreSQL host, the database name and the credentials that will be used by for storing stRDF metadata.
Compile the endpoint by calling:
```
 mvn clean package
```

The result of this action is the creation of a .war file inside the target directory.

Deploy the endpoint by placing the .war file that was created inside the webapps folder of your Tomcat installation, e.g.:
```
 sudo cp endpoint/target/strabon-endpoint-*.war /opt/tomcat/webapps/strabonendpoint.war
```
Start your Tomcat server, e.g.:

sudo systemctl start tomcat
Open a browser and go to localhost:/manager/html where is the port number you specified during Tomcat’s installation (the default port is 8080).

AI-team-UoA/Strabon