ad postgress upgrade procedure

IT/SQL/PostgreSQL/Upgrade.md

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+# Upgrading PostgreSQL Database
+
+when major release of postgresql is done you need to do some manual action
+if not done you can meet issue during request
+
+## action
+
+**need to have postgresqk-old-upgrade installed on arch**
+
+- stop service
+```systemctl stop postgresql.service```
+- rename cluster directory
+```mv /var/lib/postgres/data /var/lib/postgres/olddata
+mkdir /var/lib/postgres/data /var/lib/postgres/tmp
+chown postgres:postgres /var/lib/postgres/data /var/lib/postgres/tmp
+```
+- log in postgres account
+```
+sudo -iu postgres
+cd /var/lib/postgres/tmp
+
+```
+- launch upgrade
+```
+pg_upgrade -b /opt/pgsql-PG_VERSION/bin -B /usr/bin -d /var/lib/postgres/olddata -D /var/lib/postgres/data
+```
+- check both pg_hba.conf in new  and old cluster
+- restart server `sc-start postgresql`