云数据库 GaussDB-SNAPSHOT:示例

时间：2025-02-12 15:05:43

云数据库 GaussDB

示例

--创建数据表t1。gaussdb=# CREATE TABLE t1 (id int, name varchar);--插入数据。gaussdb=# INSERT INTO t1 VALUES (1, 'zhangsan');gaussdb=# INSERT INTO t1 VALUES (2, 'lisi');gaussdb=# INSERT INTO t1 VALUES (3, 'wangwu');gaussdb=# INSERT INTO t1 VALUES (4, 'lisa');gaussdb=# INSERT INTO t1 VALUES (5, 'jack');--创建快照。gaussdb=# CREATE SNAPSHOT s1@1.0 comment is 'first version' AS SELECT * FROM t1;--迭代创建快照。gaussdb=# CREATE SNAPSHOT s1@2.0 FROM @1.0 comment is 'inherits from @1.0' USING (INSERT VALUES(6, 'john'), (7, 'tim'); DELETE WHERE id = 1);--查看快照内容。gaussdb=# SELECT * FROM DB4AISHOT(s1@1.0); id |   name   ----+----------  1 | zhangsan  2 | lisi  3 | wangwu  4 | lisa  5 | jack(5 rows)gaussdb=# SELECT * FROM DB4AISHOT(s1@2.0); id |  name  ----+--------  2 | lisi  3 | wangwu  4 | lisa  5 | jack  6 | john  7 | tim(6 rows)--快照采样。gaussdb=# SAMPLE SNAPSHOT s1@2.0 stratify by name as nick at ratio .5;--删除快照。gaussdb=# PURGE SNAPSHOT s1@2.0;gaussdb=# PURGE SNAPSHOT s1nick@2.0;gaussdb=# PURGE SNAPSHOT s1@1.0;--删除表格t1。gaussdb=# DROP TABLE t1;