Postgresql
psql
run command from cli
psql -c "SELECT datname FROM pg_database;"
Connect to remote database:
export PGPASSWORD=password && psql --host=10.111.222.1 --port=5492 --username=user --no-password postgres
install psql
apt-get install freetds-bin
List databases
Alternative 1
SELECT datname FROM pg_database;
Alternative 2
gives more information too.
\l
Name | Owner | Encoding | Collate | Ctype | Access privileges
-------------+-------------+----------+-------------+-------------+-----------------------
indata_mdb | uc_etl_prod | UTF8 | sv_SE.UTF-8 | sv_SE.UTF-8 |
...
select database
\c testdb;
show tables
List all tables in all schemas
\dt *.*
list tables in current schema
\dt
Or from command line.
su - postgres -c "psql -c \"\\dt \" database"
schema/search_path
List current schema
SHOW search_path;
Change search path.
SET search_path TO myschema, public;
describe table
\d table;
Change view. One line per attribute
\x on
exit/quit
\q
update
UPDATE users SET admin = 1 WHERE user_id = 14002;
Create database
CREATE DATABASE dbname OWNER username;
Delete database
DROP DATABASE dbname;
delete database from cli
dropdb $dbname
Import a database
psql username -h hostname -d dbname < dump.sql
Create user
CREATE USER username WITH PASSWORD 'MYPASS';
Set super privileges
ALTER USER username WITH SUPERUSER;
List users
\du
Deleting user
DROP USER nomusr
Getting help
\? or \h
size of database
SELECT pg_size_pretty( pg_database_size('database') );
size of table
SELECT pg_size_pretty( pg_total_relation_size('tablename') );
clean archives older than 2 days
su postgres -c "/usr/pgsql-9.5/bin/pg_archivecleanup /var/lib/pgsql/9.5/archivedir/ $(basename $(find /var/lib/pgsql/9.5/archivedir/ -ctime +2 | tail -n 1))"
backup database
pg_dump -d ${dbname} > dbname_date.sql
restore database from backup
createdb -T template0 '${dbname}'
gunzip -c ${filename.gz} | psql ${dbname}
bookmarks
https://wiki.postgresql.org/wiki/Disk_Usage
clear space
\c database vacuum;
if that doesn't work do:
vacuum: freeze; or vacuum full;
autovacuum
Is autovacuum enabled.
SHOW autovacuum;
count table
SELECT COUNT(*) FROM TABLE_NAME;
If you don't need an exact count, the current statistic from the catalog table pg_class might be good enough and is much faster to retrieve for big tables.
SELECT reltuples AS approximate_row_count FROM pg_class WHERE relname = 'table_name';
nuber of connections
su - postgres -c "psql -t -c 'SELECT * FROM pg_stat_activity;'" | wc -l