Horton

Re: Support logical replication of DDLs

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: li jie <ggysxcq@gmail.com>
Cc: Ajin Cherian <itsajin@gmail.com>, rajesh singarapu <rajesh.rs0541@gmail.com>, Zheng Li <zhengli10@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Japin Li <japinli@hotmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-11-29T14:35:13Z
Lists: pgsql-hackers

Commits

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  1. Add a run_as_owner option to subscriptions.

  2. Refactor pgoutput_change().

  3. Print the correct aliases for DML target tables in ruleutils.

  4. Fix object identity string for transforms

  5. Add grantable MAINTAIN privilege and pg_maintain role.

  6. Get rid of recursion-marker values in enum AlterTableType

  7. Release cache tuple when no longer needed

  8. Empty search_path in logical replication apply worker and walsender.

  9. Refactor format_type APIs to be more modular

  10. Use wrappers of PG_DETOAST_DATUM_PACKED() more.

On Tue, 29 Nov 2022 at 17:51, li jie <ggysxcq@gmail.com> wrote:
>
> I will continue to give feedback for this patch.

Thanks a lot, that will be very helpful for us.

> 1.  LIKE STORAGE
> ```
> CREATE TABLE ctlt (a text, c text);
> ALTER TABLE ctlt ALTER COLUMN c SET STORAGE EXTERNAL;
> CREATE TABLE ctlt_storage (LIKE ctlt INCLUDING STORAGE);
> ```
>
> postgres=# \d+ ctlt_storage
>
>                                      Table "public.ctlt_storage"
>
>  Column | Type | Collation | Nullable | Default | Storage  |
> Compression | Stats target | Description
>
> --------+------+-----------+----------+---------+----------+-------------+--------------+-------------
>
>  a      | text |           |          |         | extended |
>   |              |
>
>  c      | text |           |          |         | extended |
>   |              |
>
>
> It can be seen that the storage attribute in column C of table
> ctlt_storage is not replicated.
>
> After the CREATE TABLE LIKE statement is converted,
> the LIKE STORAGE attribute is lost because it is difficult to display
> it in the CREATE TABLE syntax.
> Maybe we need to add a statement to it, like 'ALTER TABLE ctlt_storage
> ALTER COLUMN c SET STORAGE EXTERNAL;'.
>
> 2. Reference subcommand be dropped.
> ```
> create table another (f1 int, f2 text, f3 text);
>
> alter table another
>   alter f1 type text using f2 || ' and ' || f3 || ' more',
>   alter f2 type bigint using f1 * 10,
>   drop column f3;
> ```
>
> The following error occurs downstream:
> ERROR:  column "?dropped?column?" does not exist at character 206
> STATEMENT:  ALTER TABLE public.another DROP COLUMN f3 , ALTER COLUMN
> f1 SET DATA TYPE pg_catalog.text COLLATE pg_catalog."default" USING
> (((f2 OPERATOR(pg_catalog.||) ' and '::pg_catalog.text)
> OPERATOR(pg_catalog.||) "?dropped?column?") OPERATOR(pg_catalog.||) '
> more'::pg_catalog.text), ALTER COLUMN f2 SET DATA TYPE pg_catalog.int8
> USING (f1 OPERATOR(pg_catalog.*) 10)
>
> Obviously, column f3 has been deleted and its name no longer exists.
> Maybe we need to keep it and save it in advance like a drop object.
>  However,  ATLER TABLE is complex, and this problem also occurs in
> other similar scenarios.

I will analyze these issues and post a patch to handle it.

Regards,
Vignesh