文章目录
- 1、导出数据库某张表
- 2、导入某张表到数据库
- 3、查看数据库占用磁盘页数情况
- 4、查看数据库大小
- 5、查看数据表大小
- 6、查看索引大小
- 7、对数据库中表索引按照大小排序
- 8、对数据库中表按照大小排序
- 9、回收空间（建议先回收指定表）
- 10、设置主键自增序列最大值（解决insert时主键冲突）
- 11、创建索引
- 12、postgresql开启慢查询日志
- 13、查看当前正在执行的sql任务
- 14、查询pg当前连接数
- 15、查询pg最大连接数
- 16、导出导入数据库
- [17、vacuum和vacuum full区别](#17、vacuum和vacuum full区别)
- 18、只导出某张表的insert语句
- 19查询阻塞进程SQL语句
1、导出数据库某张表
pg_dump -t [表名] -f [导出文件名.sql] [数据库]
只导出insert语句：pg_dump --table=[表名] --data-only --column-inserts [数据库] > [导出文件.sql]
2、导入某张表到数据库
psql -d [数据库] -f [导入文件名.sql]
3、查看数据库占用磁盘页数情况
select a.relpages, a.reltuples, a.relfilenode,a.reltype,b.typname from pg_class a, pg_type b where a.relname like '[数据表]' and a.reltype=b.oid;
--查看数据库表的磁盘文件路径
select pg_relation_filepath('t_company_risk');
4、查看数据库大小
select pg_size_pretty(pg_database_size('[数据库]'));
5、查看数据表大小
select pg_size_pretty(pg_table_size('t_company_risk'));
6、查看索引大小
select pg_size_pretty(pg_relation_size('t_company_risk_pkey'));
select * from pg_indexes where tablename='t_company_risk'; -- 查看表的索引
7、对数据库中表索引按照大小排序
select indexrelname, pg_size_pretty(pg_relation_size(indexrelid)) from pg_stat_user_indexes where schemaname='public' order by pg_relation_size(relid) desc;
8、对数据库中表按照大小排序
select relname, pg_size_pretty(pg_relation_size(relid)) from pg_stat_user_tables where schemaname='public' order by pg_relation_size(relid) desc;
9、回收空间（建议先回收指定表）
vacuum full t_company_risk; -- 回收指定表
10、设置主键自增序列最大值（解决insert时主键冲突）
select setval('t_report_component_id_seq',(select max(id) from t_report_component));
11、创建索引
CREATE INDEX ix_t_company_risk_company_id on t_company_risk(company_id);
CREATE UNIQUE INDEX t_company_risk_pkey ON t_company_risk USING btree (insert_key);--主键索引
12、postgresql开启慢查询日志
1）修改配置文件postgres.conf
vim /data10/pgdata/postgresql.conf
2)加载配置
select pg_reload_conf();
确定是否修改
3）查看log
tail -f /data10/pgdata/pg_log/ postgresql-*.log
13、查看当前正在执行的sql任务
select * from pg_stat_activity;
select pid,application_name,client_addr,query_start,waiting,state,query from pg_stat_activity;
14、查询pg当前连接数
select count(1) from pg_stat_activity;
15、查询pg最大连接数
show max_connections;
16、导出导入数据库
su - postgres
#导出数据库
pg_dump [数据库名]> [导出文件名.sql]
#创建数据库
psql
create database [新数据库名];
#导入数据库
\q
psql -d [新数据库名] -f [导出文件名.sql];
17、vacuum和vacuum full区别
1）vacuum full会lock table ，vacuum不会。
2）vacuum只是将deadtuple的行的空间转换为能够使用的状态，额外空间一般不会返回给os（除非文件末尾有大量的连续空闲空间）。vacuum full会将这些空间碎片后面的数据上移，将数据写入一个新的磁盘文件中。
18、只导出某张表的insert语句
su - postgres
pg_dump --table=t_cascade_lower_info --data-only --column-inserts situation > t_cascade_lower_info20200818.sql
19查询阻塞进程SQL语句
SELECT blocked_locks.pid AS blocked_pid,
blocked_activity.usename AS blocked_user,
blocking_locks.pid AS blocking_pid,
blocking_activity.usename AS blocking_user,
blocked_activity.query AS blocked_statement,
blocking_activity.query AS current_statement_in_blocking_process
FROM pg_catalog.pg_locks blocked_locks
JOIN pg_catalog.pg_stat_activity blocked_activity ON blocked_activity.pid = blocked_locks.pid
JOIN pg_catalog.pg_locks blocking_locks
ON blocking_locks.locktype = blocked_locks.locktype
AND blocking_locks.database IS NOT DISTINCT FROM blocked_locks.database
AND blocking_locks.relation IS NOT DISTINCT FROM blocked_locks.relation
AND blocking_locks.page IS NOT DISTINCT FROM blocked_locks.page
AND blocking_locks.tuple IS NOT DISTINCT FROM blocked_locks.tuple
AND blocking_locks.virtualxid IS NOT DISTINCT FROM blocked_locks.virtualxid
AND blocking_locks.transactionid IS NOT DISTINCT FROM blocked_locks.transactionid
AND blocking_locks.classid IS NOT DISTINCT FROM blocked_locks.classid
AND blocking_locks.objid IS NOT DISTINCT FROM blocked_locks.objid
AND blocking_locks.objsubid IS NOT DISTINCT FROM blocked_locks.objsubid
AND blocking_locks.pid != blocked_locks.pid
JOIN pg_catalog.pg_stat_activity blocking_activity ON blocking_activity.pid = blocking_locks.pid
WHERE NOT blocked_locks.granted;