RE: Support logical replication of DDLs

On Thur, Jun 8, 2023 20:02 PM shveta malik <shveta.malik@gmail.com> wrote:
> Thank You Vignesh for handling (a), Ajin for handling (b), Shi-san and
> Hou-san for contributing in (c).
> 
> The new changes are in patch 0001, 0002, 0005 and 0008.

Thanks for updating the patch set.

Here are some comments:
===
For 0002 patch.
1. The typo atop the function EventTriggerTableInitWrite.
```
+/*
+ * Fire table_init_rewrite triggers.
+ */
+void
+EventTriggerTableInitWrite(Node *real_create, ObjectAddress address)
```
s/table_init_rewrite/table_init_write

~~~

2. The new process for "SCT_CreateTableAs" in the function pg_event_trigger_ddl_commands.
With the event trigger created in
test_ddl_deparse_regress/sql/test_ddl_deparse.sql, when creating the table that
already exists with `CreateTableAs` command, an error is raised like below:
```
postgres=# CREATE TABLE IF NOT EXISTS as_select1 AS SELECT * FROM pg_class WHERE relkind = 'r';
postgres=# CREATE TABLE IF NOT EXISTS as_select1 AS SELECT * FROM pg_class WHERE relkind = 'r';
NOTICE:  relation "as_select1" already exists, skipping
ERROR:  unrecognized object class: 0
CONTEXT:  PL/pgSQL function test_ddl_deparse() line 6 at FOR over SELECT rows
```
It seems that we could check cmd->d.ctas.real_create in the function
pg_event_trigger_ddl_commands and return NULL in this case.

===
For 0004 patch.
3. The command tags that are not supported for deparsing in the tests.
```
    FOR r IN SELECT * FROM pg_event_trigger_ddl_commands()
        -- Some TABLE commands generate sequence-related commands, also deparse them.
        WHERE command_tag in ('ALTER FOREIGN TABLE', 'ALTER TABLE',
                              'CREATE FOREIGN TABLE', 'CREATE TABLE',
                              'CREATE TABLE AS', 'DROP FOREIGN TABLE',
                              'DROP TABLE', 'ALTER SEQUENCE',
                              'CREATE SEQUENCE', 'DROP SEQUENCE')
```
Since foreign table is not supported yet in the current patch set, it seems that
we need to remove "FOREIGN TABLE" related command tag. If so, I think the
following three files need to be modified:
- test_ddl_deparse_regress/sql/test_ddl_deparse.sql
- test_ddl_deparse_regress/t/001_compare_dumped_results.pl
- test_ddl_deparse_regress/t/002_regress_tests.pl

~~~

4. The different test items between meson and Makefile.
It seems that we should keep the same SQL files and the same order of SQL files
in test_ddl_deparse_regress/meson.build and test_ddl_deparse_regress/Makefile.

===
For 0004 && 0008 patches.
5. The test cases in the test file test_ddl_deparse_regress/t/001_compare_dumped_results.pl.
```
# load test cases from the regression tests
-my @regress_tests = split /\s+/, $ENV{REGRESS};
+#my @regress_tests = split /\s+/, $ENV{REGRESS};
+my @regress_tests = ("create_type", "create_schema", "create_rule", "create_index");
```
I think @regress_tests should include all SQL files, instead of just four. BTW,
the old way (using `split /\s+/, $ENV{REGRESS}`) doesn't work in meson.

Regards,
Wang wei