PostgreSQL/Postgres

init data store

initdb -D /Users/dcai/.local/var/postgres12

start sever with data store

postgres -D ~/.local/var/postgres12/

create super user

createuser -s postgres

update user password

ALTER USER postgres WITH PASSWORD 'xxxxx';

Backup
pg_dump -h localhost -U postgres -F c -f "~/dbbackup/" dbname
Restore
pg_restore -h localhost -U postgres -d old_db "~/dbbackup/"
Drop index
echo "DROP INDEX mdl_quiz_xxx_idx" | sudo psql -U postgres moodle_19
Handle large db

backup 

pg_dump dbname | gzip > filename.gz

restore 

gunzip -c filename.gz | psql dbname
cat filename.gz | gunzip | psql dbname