Re: Persistent changes in rolled-back transactions
| От | Rui DeSousa |
|---|---|
| Тема | Re: Persistent changes in rolled-back transactions |
| Дата | |
| Msg-id | 9B0F9F61-113F-419E-BC6B-12C9DE0D5BE9@crazybean.net обсуждение исходный текст |
| Ответ на | Re: Persistent changes in rolled-back transactions ("David G. Johnston" <david.g.johnston@gmail.com>) |
| Ответы |
Re: Persistent changes in rolled-back transactions
|
| Список | pgsql-admin |
On Nov 9, 2022, at 8:23 PM, David G. Johnston <david.g.johnston@gmail.com> wrote:Or just read the documentation for the current version (I seem to recall it used to be non-transactional, maybe...doesn't matter now).
In a lot of other databases DDL is not transactional and truncate is DDL — most likely confusing it with another RDBMS systems.
DDL is transactional in PostgreSQL thus you can even rollback table changes, etc. which is not possible in other RDBMS systems.
prod=# create table demo (a int);
CREATE TABLE
prod=#
prod=# \d+ demo;
Table "dev.demo"
Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
--------+---------+-----------+----------+---------+---------+-------------+--------------+-------------
a | integer | | | | plain | | |
Access method: heap
prod=# begin;
BEGIN
prod=*# alter table demo add column b int;
ALTER TABLE
prod=*# \d+ demo;
Table "dev.demo"
Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
--------+---------+-----------+----------+---------+---------+-------------+--------------+-------------
a | integer | | | | plain | | |
b | integer | | | | plain | | |
Access method: heap
prod=*# rollback;
ROLLBACK
prod=# \d+ demo;
Table "dev.demo"
Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
--------+---------+-----------+----------+---------+---------+-------------+--------------+-------------
a | integer | | | | plain | | |
Access method: heap
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