一、查看数据库当前连接状态
1、.查看被锁定表：SELECT pg_class.relname AS table, pg_database.datname AS database,pid, mode, granted FROM pg_locks, pg_class, pg_database WHERE pg_locks.relation= pg_class.oid AND pg_locks.database = pg_database.oid;
2、查看客户端连接情况：SELECTclient_addr ,client_port,waiting,query_start,current_query FROMpg_stat_activity;
3、查看数据库大小：SELECTpg_size_pretty(pg_database_size('MTPS')) As fulldbsize;
4、查看表结构：select* from information_schema.columns；
5、显示默认表空间：showdefault_tablespace;
6、查看Postgresql的连接状况：select* from pg_stat_activity;
7、查看数据库表大小：selectrelname, pg_size_pretty(pg_relation_size('relname')) frompg_stat_user_tables where schemaname = 'public' order bypg_relation_size('relname') desc;
查看单个表的大小：selectpg_size_pretty(pg_relation_size('table_name'));
8、查看主从复制状态：SELECT * from pg_stat_replication ;
9、查看主从状态：SELECT* from pg_is_in_recovery();
10、暂停/恢复主从复制：pg_xlog_replay_pause()；
pg_xlog_replay_resume()；
二、psql
1、修改密码：alteruser postgres with password 'new password'
2、创建库并引用postgis模板：createdatabase cetcnav template postgis;
3、修改库的属主：alterdatabase cetcnav owner to terra;
4、添加索引：CREATEINDEX t_gps_20131111_idx_vehicle_id ON t1(list);
5、删除索引：dropINDEX t_gps_20131111_idx_vehicle_id;
6、插入数据：INSERTINTO t_vehicle_login (vehicle_id,password) select id,snumber from t_vehicle;
7、过滤重复：SELECTdistinct(vehicle_id),vnumber,snumber,warrant_code,warrant_result fromt_vehicle_warrant；根据某个字段去重
8、导出授权的用户：pg_dumpall -h localhost -U postgres -v --roles-only -f test.sql；
9、创建用户：CREATEUSER user1 WITH PASSWORD '123456';
三、查看数据库系统参数
1、设置执行超过指定秒数的sql语句输出到日志 ：log_min_duration_statement= 3
2、查看客户端编码：showclient_encoding;
3、退出postgres=#\q
退出 -bash-4.2$exit