PostgreSQL 如何实现批量更新、删除、插入

标签

PostgreSQL , 批量 , batch , insert , update , delete , copy

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背景

如何一次插入多条记录？

如何一次更新多条记录？

如何一次批量删除多条记录？

批量操作可以减少数据库与应用程序的交互次数，提高数据处理的吞吐量。

批量插入

批量插入1

使用insert into ... select的方法

postgres=# insert into tbl1 (id, info ,crt_time) select generate_series(1,10000),'test',now(); INSERT 0 10000 postgres=# select count(*) from tbl1; count ------- 10001 (1 row)

批量插入2

使用values(),(),...();的方法

postgres=# insert into tbl1 (id,info,crt_time) values (1,'test',now()), (2,'test2',now()), (3,'test3',now()); INSERT 0 3

批量插入3

BEGIN; ...多条insert...; END;

严格来说，这应该不属于批量，但是可以减少事务提交时的同步等待。同样有性能提升的效果。

postgres=# begin; BEGIN postgres=# insert into tbl1 (id,info,crt_time) values (1,'test',now()); INSERT 0 1 postgres=# insert into tbl1 (id,info,crt_time) values (2,'test2',now()); INSERT 0 1 postgres=# insert into tbl1 (id,info,crt_time) values (3,'test3',now()); INSERT 0 1 postgres=# end; COMMIT

批量插入4

copy

copy协议与insert协议不一样，更加精简，插入效率高。

test03=# \d test Table "public.test" Column | Type | Modifiers ----------+-----------------------------+----------- id | integer | not null info | text | crt_time | timestamp without time zone | Indexes: "test_pkey" PRIMARY KEY, btree (id) test03=# copy test from stdin; Enter data to be copied followed by a newline. End with a backslash and a period on a line by itself. >> 8 'test' '2017-01-01' >> 9 'test9' '2017-02-02' >> \. COPY 2

不同的语言驱动，对应的COPY接口不一样。

参考

https://jdbc.postgresql.org/documentation/publicapi/index.html

https://www.postgresql.org/docs/9.6/static/libpq-copy.html

批量更新

批量更新

test03=# update test set info=tmp.info from (values (1,'new1'),(2,'new2'),(6,'new6')) as tmp (id,info) where test.id=tmp.id; UPDATE 3 test03=# select * from test; id | info | crt_time ----+--------------+---------------------------- 3 | hello | 2017-04-24 15:31:49.14291 4 | digoal0123 | 2017-04-24 15:42:50.912887 5 | hello digoal | 2017-04-24 15:57:29.622045 1 | new1 | 2017-04-24 15:58:55.610072 2 | new2 | 2017-04-24 15:28:20.37392 6 | new6 | 2017-04-24 15:59:12.265915 (6 rows)

批量删除

批量删除

test03=# delete from test using (values (3),(4),(5)) as tmp(id) where test.id=tmp.id; DELETE 3 test03=# select * from test; id | info | crt_time ----+---------+---------------------------- 1 | new1 | 2017-04-24 15:58:55.610072 2 | new2 | 2017-04-24 15:28:20.37392 6 | new6 | 2017-04-24 15:59:12.265915

如果要清除全表，建议使用truncate

test03=# set lock_timeout = '1s'; SET test03=# truncate test; TRUNCATE TABLE test03=# select * from test; id | info | crt_time ----+------+---------- (0 rows) 相关资源：Postgresql数据库批量导入其他pg库的表