Re: CREATE TABLE LIKE INCLUDING TRIGGERS

On Thu, May 7, 2026 at 9:38 AM Henson Choi <assam258(at)gmail(dot)com> wrote:
>
> MINOR ISSUES
> ------------
>
> 1. Test: cross-file dependency on trigger_func (create_table_like.sql)
>
> create_table_like.sql references trigger_func without creating it,
> relying on triggers.sql having run first. The dependency is noted
> in a comment, and parallel_schedule guarantees the correct order for
> a full "make check" run. However, "make check TESTS=create_table_like"
> will fail because trigger_func does not exist.
>
> PostgreSQL convention is that each test file creates and drops the
> objects it needs. Please add a local definition of trigger_func in
> create_table_like.sql (and drop it at the end of the new block).
>
OK.

> 2. Test: EXCLUDING TRIGGERS not exercised
>
> The grammar now accepts EXCLUDING TRIGGERS, but no test uses it.
> The default (no option) is equivalent, but a one-line smoke test
> would confirm the keyword is accepted and has the expected effect:
>
> CREATE TABLE t_excl (LIKE source_table EXCLUDING TRIGGERS);
>
OK.

> 3. Documentation: create_table.sgml wording inconsistent with
> create_foreign_table.sgml
>
> create_foreign_table.sgml already reads:
>
> "All non-internal triggers are copied to the new table."
>
> create_table.sgml reads:
>
> "All non-internal triggers on the original table will be created
> on the new table."
>
> Recommended wording for create_table.sgml:
>
> "All non-internal triggers are copied to the new table."
>
OK.

> 4. Code comment: capitalisation in generateClonedTriggerStmt()
> (trigger.c)
>
> /* Reconstruct trigger function String list */
>
> "String" should be lowercase "string".
>
Other places also have "String list", it refers to the T_String node type.

> 5. Code comment: overly verbose in expandTableLikeClause()
> (parse_utilcmd.c)
>
> /* We make use of CreateTrigStmt's trigcomment option */
>
> The code is self-explanatory. I would recommend removing it or
> replacing it with something like:
>
> /* pass comment through to CreateTrigger */
>

Other places in parse_utilcmd.c have:
/*
* We make use of IndexStmt's idxcomment option, so as not to
* need to know now what name the index will have.
*/

/*
* We make use of CreateStatsStmt's stxcomment option, so as
* not to need to know now what name the statistics will have.
*/

We can change it to:
/*
* We make use of CreateTrigStmt's trigcomment option, so as
* not to need to know now what name the triggers will have.
*/

>
> 7. Whole-row reference restriction: implementation gap or deliberate?
>
> Triggers whose WHEN clause contains a whole-row reference (OLD.*,
> NEW.*) are rejected. Is this a deliberate decision, or a known gap
> left for a follow-up? If the latter, a XXX comment at the rejection
> site would help future contributors:
>
> /*
> * XXX: whole-row Vars could in principle be handled by passing the
> * target table's composite type OID as to_rowtype, but
> * generateClonedTriggerStmt() currently has no access to it.
> */
>

Other places already reject it (search found_whole_row in parse_utilcmd.c).
It cannot be supported because the source table's whole-row type
differs from the target table's whole-row type.

The v10 in https://www.postgresql.org/message-id/CACJufxEcKTa5DaDJS%3DZ25xezCEyuLbSzORDSmT4%3DjyZymsAK8A%40mail.gmail.com
has addressed most of the issues mentioned above.

Only issue remaining is changing one of the comments to
/*
* We make use of CreateTrigStmt's trigcomment option, so as
* not to need to know now what name the triggers will have.
*/