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  1. Disallow collecting transition tuples from child foreign tables.

  1. Problem with transition tables on partitioned tables with foreign-table partitions

    Etsuro Fujita <etsuro.fujita@gmail.com> — 2025-07-01T02:55:29Z

    Hi,

While working on something else, I noticed that while we disallow
transition tables on foreign tables, we allow transition tables on
partitioned tables with foreign-table partitions, which produces
incorrect results.  Here is an example using postgres_fdw:

create table parent (a text, b int) partition by list (a);
create table loct (a text, b int);
create foreign table child (a text, b int)
  server loopback options (table_name 'loct');
alter table parent attach partition child for values in ('AAA');

create function dump_insert() returns trigger language plpgsql as
$$
  begin
    raise notice 'trigger = %, new table = %',
                 TG_NAME,
                 (select string_agg(new_table::text, ', ' order by a)
from new_table);
    return null;
  end;
$$;
create trigger parent_insert_trig
  after insert on parent referencing new table as new_table
  for each statement execute procedure dump_insert();

create function intercept_insert() returns trigger language plpgsql as
$$
  begin
    new.b = new.b + 1000;
    return new;
  end;
$$;
create trigger intercept_insert_loct
  before insert on loct
  for each row execute procedure intercept_insert();

insert into parent values ('AAA', 42);
NOTICE:  trigger = parent_insert_trig, new table = (AAA,42)
INSERT 0 1

The trigger shows the original tuple created by the core, not the
actual tuple inserted into the foreign-table partition, as
postgres_fdw does not collect the actual tuple, of course!

UPDATE/DELETE also produce incorrect results:

create function dump_update() returns trigger language plpgsql as
$$
  begin
    raise notice 'trigger = %, old table = %, new table = %',
                 TG_NAME,
                 (select string_agg(old_table::text, ', ' order by a)
from old_table),
                 (select string_agg(new_table::text, ', ' order by a)
from new_table);
    return null;
  end;
$$;
create trigger parent_update_trig
  after update on parent referencing old table as old_table new table
as new_table
  for each statement execute procedure dump_update();

update parent set b = b + 1;
NOTICE:  trigger = parent_update_trig, old table = <NULL>, new table = <NULL>
UPDATE 1

create function dump_delete() returns trigger language plpgsql as
$$
  begin
    raise notice 'trigger = %, old table = %',
                 TG_NAME,
                 (select string_agg(old_table::text, ', ' order by a)
from old_table);
    return null;
  end;
$$;
create trigger parent_delete_trig
  after delete on parent referencing old table as old_table
  for each statement execute procedure dump_delete();

delete from parent;
NOTICE:  trigger = parent_delete_trig, old table = <NULL>
DELETE 1

In both cases the triggers fail to show transition tuples.  The cause
of this is that postgres_fdw mistakenly performs direct modify for
UPDATE/DELETE on the partition, which skips
ExecARUpdateTriggers()/ExecARDeleteTriggers() entirely.

To fix, I think we could disallow creating transition-table triggers
on such partitioned tables, but I think that that is too restrictive
because some users might have been using such triggers, avoiding this
problem by e.g., modifying only plain-table partitions.  So I would
like to propose to fix this by the following: 1) disable using direct
modify to modify foreign-table partitions if there are any
transition-table triggers on the partitioned table, and then 2) throw
an error in ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
if they collects transition tuple(s) from a foreign-table partition.

Attached is a WIP patch for that.

Best regards,
Etsuro Fujita

  2. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Amit Langote <amitlangote09@gmail.com> — 2025-07-01T07:42:12Z

    Hi Fujita-san,

On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
>
> Hi,
>
> While working on something else, I noticed that while we disallow
> transition tables on foreign tables, we allow transition tables on
> partitioned tables with foreign-table partitions, which produces
> incorrect results.  Here is an example using postgres_fdw:
>
> create table parent (a text, b int) partition by list (a);
> create table loct (a text, b int);
> create foreign table child (a text, b int)
>   server loopback options (table_name 'loct');
> alter table parent attach partition child for values in ('AAA');
>
> create function dump_insert() returns trigger language plpgsql as
> $$
>   begin
>     raise notice 'trigger = %, new table = %',
>                  TG_NAME,
>                  (select string_agg(new_table::text, ', ' order by a)
> from new_table);
>     return null;
>   end;
> $$;
> create trigger parent_insert_trig
>   after insert on parent referencing new table as new_table
>   for each statement execute procedure dump_insert();
>
> create function intercept_insert() returns trigger language plpgsql as
> $$
>   begin
>     new.b = new.b + 1000;
>     return new;
>   end;
> $$;
> create trigger intercept_insert_loct
>   before insert on loct
>   for each row execute procedure intercept_insert();
>
> insert into parent values ('AAA', 42);
> NOTICE:  trigger = parent_insert_trig, new table = (AAA,42)
> INSERT 0 1
>
> The trigger shows the original tuple created by the core, not the
> actual tuple inserted into the foreign-table partition, as
> postgres_fdw does not collect the actual tuple, of course!

Maybe I'm missing something, but given that the intercept_insert()
function is applied during the "remote" operation, isn't it expected
that the parent table's trigger for a "local" operation shows the
original tuple?

> UPDATE/DELETE also produce incorrect results:
>
> create function dump_update() returns trigger language plpgsql as
> $$
>   begin
>     raise notice 'trigger = %, old table = %, new table = %',
>                  TG_NAME,
>                  (select string_agg(old_table::text, ', ' order by a)
> from old_table),
>                  (select string_agg(new_table::text, ', ' order by a)
> from new_table);
>     return null;
>   end;
> $$;
> create trigger parent_update_trig
>   after update on parent referencing old table as old_table new table
> as new_table
>   for each statement execute procedure dump_update();
>
> update parent set b = b + 1;
> NOTICE:  trigger = parent_update_trig, old table = <NULL>, new table = <NULL>
> UPDATE 1
>
> create function dump_delete() returns trigger language plpgsql as
> $$
>   begin
>     raise notice 'trigger = %, old table = %',
>                  TG_NAME,
>                  (select string_agg(old_table::text, ', ' order by a)
> from old_table);
>     return null;
>   end;
> $$;
> create trigger parent_delete_trig
>   after delete on parent referencing old table as old_table
>   for each statement execute procedure dump_delete();
>
> delete from parent;
> NOTICE:  trigger = parent_delete_trig, old table = <NULL>
> DELETE 1
>
> In both cases the triggers fail to show transition tuples.  The cause
> of this is that postgres_fdw mistakenly performs direct modify for
> UPDATE/DELETE on the partition, which skips
> ExecARUpdateTriggers()/ExecARDeleteTriggers() entirely.

Yes, that seems problematic.

> To fix, I think we could disallow creating transition-table triggers
> on such partitioned tables, but I think that that is too restrictive
> because some users might have been using such triggers, avoiding this
> problem by e.g., modifying only plain-table partitions.

+1

>  So I would
> like to propose to fix this by the following: 1) disable using direct
> modify to modify foreign-table partitions if there are any
> transition-table triggers on the partitioned table, and then 2) throw
> an error in ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
> if they collects transition tuple(s) from a foreign-table partition.

Is (2) intended to catch cases that occur during a foreign insert and
foreign/non-direct update/delete?

-- 
Thanks, Amit Langote

  3. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Etsuro Fujita <etsuro.fujita@gmail.com> — 2025-07-02T10:05:23Z

    Hi Amit-san,

On Tue, Jul 1, 2025 at 4:42 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> > While working on something else, I noticed that while we disallow
> > transition tables on foreign tables, we allow transition tables on
> > partitioned tables with foreign-table partitions, which produces
> > incorrect results.  Here is an example using postgres_fdw:
> >
> > create table parent (a text, b int) partition by list (a);
> > create table loct (a text, b int);
> > create foreign table child (a text, b int)
> >   server loopback options (table_name 'loct');
> > alter table parent attach partition child for values in ('AAA');
> >
> > create function dump_insert() returns trigger language plpgsql as
> > $$
> >   begin
> >     raise notice 'trigger = %, new table = %',
> >                  TG_NAME,
> >                  (select string_agg(new_table::text, ', ' order by a)
> > from new_table);
> >     return null;
> >   end;
> > $$;
> > create trigger parent_insert_trig
> >   after insert on parent referencing new table as new_table
> >   for each statement execute procedure dump_insert();
> >
> > create function intercept_insert() returns trigger language plpgsql as
> > $$
> >   begin
> >     new.b = new.b + 1000;
> >     return new;
> >   end;
> > $$;
> > create trigger intercept_insert_loct
> >   before insert on loct
> >   for each row execute procedure intercept_insert();
> >
> > insert into parent values ('AAA', 42);
> > NOTICE:  trigger = parent_insert_trig, new table = (AAA,42)
> > INSERT 0 1
> >
> > The trigger shows the original tuple created by the core, not the
> > actual tuple inserted into the foreign-table partition, as
> > postgres_fdw does not collect the actual tuple, of course!
>
> Maybe I'm missing something, but given that the intercept_insert()
> function is applied during the "remote" operation, isn't it expected
> that the parent table's trigger for a "local" operation shows the
> original tuple?

That is the question of how we define the after image of a row
inserted into a foreign table, but consider the case where the
partition is a plain table:

create table parent (a text, b int) partition by list (a);
create table child partition of parent for values in ('AAA');
create trigger intercept_insert_child
  before insert on child
  for each row execute procedure intercept_insert();
insert into parent values ('AAA', 42);
NOTICE:  trigger = parent_insert_trig, new table = (AAA,1042)
INSERT 0 1

The trigger shows the final tuple, not the original tuple.  So from a
consistency perspective, I thought it would be good if the trigger
does so even in the case where the partition is a foreign table.

> >  So I would
> > like to propose to fix this by the following: 1) disable using direct
> > modify to modify foreign-table partitions if there are any
> > transition-table triggers on the partitioned table, and then 2) throw
> > an error in ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
> > if they collects transition tuple(s) from a foreign-table partition.
>
> Is (2) intended to catch cases that occur during a foreign insert and
> foreign/non-direct update/delete?

That is right; the patch forces the FDW to perform ExecForeign*
functions, and then throws an error in ExecAR* functions.  One good
thing about this is that we are able to avoid throwing the error when
local/remote row-level BEFORE triggers return NULL.

Thanks for the comments!

Best regards,
Etsuro Fujita

  4. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Amit Langote <amitlangote09@gmail.com> — 2025-07-02T13:05:09Z

    On Wed, Jul 2, 2025 at 7:05 PM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> On Tue, Jul 1, 2025 at 4:42 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> > > While working on something else, I noticed that while we disallow
> > > transition tables on foreign tables, we allow transition tables on
> > > partitioned tables with foreign-table partitions, which produces
> > > incorrect results.  Here is an example using postgres_fdw:
> > >
> > > create table parent (a text, b int) partition by list (a);
> > > create table loct (a text, b int);
> > > create foreign table child (a text, b int)
> > >   server loopback options (table_name 'loct');
> > > alter table parent attach partition child for values in ('AAA');
> > >
> > > create function dump_insert() returns trigger language plpgsql as
> > > $$
> > >   begin
> > >     raise notice 'trigger = %, new table = %',
> > >                  TG_NAME,
> > >                  (select string_agg(new_table::text, ', ' order by a)
> > > from new_table);
> > >     return null;
> > >   end;
> > > $$;
> > > create trigger parent_insert_trig
> > >   after insert on parent referencing new table as new_table
> > >   for each statement execute procedure dump_insert();
> > >
> > > create function intercept_insert() returns trigger language plpgsql as
> > > $$
> > >   begin
> > >     new.b = new.b + 1000;
> > >     return new;
> > >   end;
> > > $$;
> > > create trigger intercept_insert_loct
> > >   before insert on loct
> > >   for each row execute procedure intercept_insert();
> > >
> > > insert into parent values ('AAA', 42);
> > > NOTICE:  trigger = parent_insert_trig, new table = (AAA,42)
> > > INSERT 0 1
> > >
> > > The trigger shows the original tuple created by the core, not the
> > > actual tuple inserted into the foreign-table partition, as
> > > postgres_fdw does not collect the actual tuple, of course!
> >
> > Maybe I'm missing something, but given that the intercept_insert()
> > function is applied during the "remote" operation, isn't it expected
> > that the parent table's trigger for a "local" operation shows the
> > original tuple?
>
> That is the question of how we define the after image of a row
> inserted into a foreign table, but consider the case where the
> partition is a plain table:
>
> create table parent (a text, b int) partition by list (a);
> create table child partition of parent for values in ('AAA');
> create trigger intercept_insert_child
>   before insert on child
>   for each row execute procedure intercept_insert();
> insert into parent values ('AAA', 42);
> NOTICE:  trigger = parent_insert_trig, new table = (AAA,1042)
> INSERT 0 1
>
> The trigger shows the final tuple, not the original tuple.  So from a
> consistency perspective, I thought it would be good if the trigger
> does so even in the case where the partition is a foreign table.

Ok, but if you define the trigger on the foreign table partition
(child) as follows, you do get what I think is the expected result?

create trigger intercept_insert_foreign_child
  before insert on child
  for each row execute procedure intercept_insert();

insert into parent values ('AAA', 42);
NOTICE:  trigger = parent_insert_trig, new table = (AAA,1042)

-- 2042, because row modified by both triggers
table parent;
  a  |  b
-----+------
 AAA | 2042
(1 row)

Or perhaps you're saying that the row returned by this line in ExecInsert():

       /*
         * insert into foreign table: let the FDW do it
         */
        slot = resultRelInfo->ri_FdwRoutine->ExecForeignInsert(estate,
                                                               resultRelInfo,
                                                               slot,
                                                               planSlot);

is not the expected "after image", and thus should not be added to the
parent's transition table?

IIUC, to prevent that, we now hit the following error in:

void
ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
                     TupleTableSlot *slot, List *recheckIndexes,
                     TransitionCaptureState *transition_capture)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;

    if (relinfo->ri_FdwRoutine && transition_capture &&
        transition_capture->tcs_insert_new_table)
    {
        Assert(relinfo->ri_RootResultRelInfo);
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot collect transition tuples from child
foreign tables")));
    }

> > >  So I would
> > > like to propose to fix this by the following: 1) disable using direct
> > > modify to modify foreign-table partitions if there are any
> > > transition-table triggers on the partitioned table, and then 2) throw
> > > an error in ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
> > > if they collects transition tuple(s) from a foreign-table partition.
> >
> > Is (2) intended to catch cases that occur during a foreign insert and
> > foreign/non-direct update/delete?
>
> That is right; the patch forces the FDW to perform ExecForeign*
> functions, and then throws an error in ExecAR* functions.  One good
> thing about this is that we are able to avoid throwing the error when
> local/remote row-level BEFORE triggers return NULL.

Given my question above, I’m not sure I fully understand the intention
behind adding these checks.

-- 
Thanks, Amit Langote

  5. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Etsuro Fujita <etsuro.fujita@gmail.com> — 2025-07-03T05:04:41Z

    On Wed, Jul 2, 2025 at 10:05 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Wed, Jul 2, 2025 at 7:05 PM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> > On Tue, Jul 1, 2025 at 4:42 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > > On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> > > > While working on something else, I noticed that while we disallow
> > > > transition tables on foreign tables, we allow transition tables on
> > > > partitioned tables with foreign-table partitions, which produces
> > > > incorrect results.  Here is an example using postgres_fdw:
> > > >
> > > > create table parent (a text, b int) partition by list (a);
> > > > create table loct (a text, b int);
> > > > create foreign table child (a text, b int)
> > > >   server loopback options (table_name 'loct');
> > > > alter table parent attach partition child for values in ('AAA');
> > > >
> > > > create function dump_insert() returns trigger language plpgsql as
> > > > $$
> > > >   begin
> > > >     raise notice 'trigger = %, new table = %',
> > > >                  TG_NAME,
> > > >                  (select string_agg(new_table::text, ', ' order by a)
> > > > from new_table);
> > > >     return null;
> > > >   end;
> > > > $$;
> > > > create trigger parent_insert_trig
> > > >   after insert on parent referencing new table as new_table
> > > >   for each statement execute procedure dump_insert();
> > > >
> > > > create function intercept_insert() returns trigger language plpgsql as
> > > > $$
> > > >   begin
> > > >     new.b = new.b + 1000;
> > > >     return new;
> > > >   end;
> > > > $$;
> > > > create trigger intercept_insert_loct
> > > >   before insert on loct
> > > >   for each row execute procedure intercept_insert();
> > > >
> > > > insert into parent values ('AAA', 42);
> > > > NOTICE:  trigger = parent_insert_trig, new table = (AAA,42)
> > > > INSERT 0 1
> > > >
> > > > The trigger shows the original tuple created by the core, not the
> > > > actual tuple inserted into the foreign-table partition, as
> > > > postgres_fdw does not collect the actual tuple, of course!
> > >
> > > Maybe I'm missing something, but given that the intercept_insert()
> > > function is applied during the "remote" operation, isn't it expected
> > > that the parent table's trigger for a "local" operation shows the
> > > original tuple?
> >
> > That is the question of how we define the after image of a row
> > inserted into a foreign table, but consider the case where the
> > partition is a plain table:
> >
> > create table parent (a text, b int) partition by list (a);
> > create table child partition of parent for values in ('AAA');
> > create trigger intercept_insert_child
> >   before insert on child
> >   for each row execute procedure intercept_insert();
> > insert into parent values ('AAA', 42);
> > NOTICE:  trigger = parent_insert_trig, new table = (AAA,1042)
> > INSERT 0 1
> >
> > The trigger shows the final tuple, not the original tuple.  So from a
> > consistency perspective, I thought it would be good if the trigger
> > does so even in the case where the partition is a foreign table.
>
> Ok, but if you define the trigger on the foreign table partition
> (child) as follows, you do get what I think is the expected result?
>
> create trigger intercept_insert_foreign_child
>   before insert on child
>   for each row execute procedure intercept_insert();
>
> insert into parent values ('AAA', 42);
> NOTICE:  trigger = parent_insert_trig, new table = (AAA,1042)
>
> -- 2042, because row modified by both triggers
> table parent;
>   a  |  b
> -----+------
>  AAA | 2042
> (1 row)
>
> Or perhaps you're saying that the row returned by this line in ExecInsert():
>
>        /*
>          * insert into foreign table: let the FDW do it
>          */
>         slot = resultRelInfo->ri_FdwRoutine->ExecForeignInsert(estate,
>                                                                resultRelInfo,
>                                                                slot,
>                                                                planSlot);
>
> is not the expected "after image", and thus should not be added to the
> parent's transition table?

Yes, that is what I mean by "postgres_fdw does not collect the actual
tuple, of course!" above.  My explanation was not good, though.

> IIUC, to prevent that, we now hit the following error in:
>
> void
> ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
>                      TupleTableSlot *slot, List *recheckIndexes,
>                      TransitionCaptureState *transition_capture)
> {
>     TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
>
>     if (relinfo->ri_FdwRoutine && transition_capture &&
>         transition_capture->tcs_insert_new_table)
>     {
>         Assert(relinfo->ri_RootResultRelInfo);
>         ereport(ERROR,
>                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                  errmsg("cannot collect transition tuples from child
> foreign tables")));
>     }

Right, I added the check for that.

Thanks!

Best regards,
Etsuro Fujita

  6. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Etsuro Fujita <etsuro.fujita@gmail.com> — 2025-07-09T08:06:39Z

    On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> So I would
> like to propose to fix this by the following: 1) disable using direct
> modify to modify foreign-table partitions if there are any
> transition-table triggers on the partitioned table, and then 2) throw
> an error in ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
> if they collects transition tuple(s) from a foreign-table partition.
>
> Attached is a WIP patch for that.

Here is an updated version of the patch, in which I added 1) an Assert
to ExecAR* functions to ensure that the passed-in ResultRelInfo
pointer is not NULL, 2) added/tweaked comments a bit more, and 3)
added regression tests.

Best regards,
Etsuro Fujita

  7. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Amit Langote <amitlangote09@gmail.com> — 2025-07-10T13:20:09Z

    Fujita-san,

On Wed, Jul 9, 2025 at 5:07 PM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> > So I would
> > like to propose to fix this by the following: 1) disable using direct
> > modify to modify foreign-table partitions if there are any
> > transition-table triggers on the partitioned table, and then 2) throw
> > an error in ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
> > if they collects transition tuple(s) from a foreign-table partition.
> >
> > Attached is a WIP patch for that.
>
> Here is an updated version of the patch, in which I added 1) an Assert
> to ExecAR* functions to ensure that the passed-in ResultRelInfo
> pointer is not NULL, 2) added/tweaked comments a bit more, and 3)
> added regression tests.

Thanks for the new patch.  LGTM.

While reading it, I noticed that the functions performing table_open()
are repeatedly called in this condition, which runs for every
qualifying foreign child relations:

        if (fdwroutine != NULL &&
            fdwroutine->PlanDirectModify != NULL &&
            fdwroutine->BeginDirectModify != NULL &&
            fdwroutine->IterateDirectModify != NULL &&
            fdwroutine->EndDirectModify != NULL &&
            withCheckOptionLists == NIL &&
            !has_row_triggers(root, rti, operation) &&
            !has_stored_generated_columns(root, rti))

That seems a bit expensive. It might be worth using *_valid flags to
avoid redundant table_open() calls like you're doing for transition
table checking. Maybe something to consider in a separate patch.

-- 
Thanks, Amit Langote

  8. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Amit Langote <amitlangote09@gmail.com> — 2025-07-10T14:54:41Z

    On Thu, Jul 10, 2025 at 22:20 Amit Langote <amitlangote09@gmail.com> wrote:

> Fujita-san,
>
> On Wed, Jul 9, 2025 at 5:07 PM Etsuro Fujita <etsuro.fujita@gmail.com>
> wrote:
> > On Tue, Jul 1, 2025 at 11:55 AM Etsuro Fujita <etsuro.fujita@gmail.com>
> wrote:
> > > So I would
> > > like to propose to fix this by the following: 1) disable using direct
> > > modify to modify foreign-table partitions if there are any
> > > transition-table triggers on the partitioned table, and then 2) throw
> > > an error in
> ExecARInsertTriggers()/ExecARUpdateTriggers()/ExecARDeleteTriggers()
> > > if they collects transition tuple(s) from a foreign-table partition.
> > >
> > > Attached is a WIP patch for that.
> >
> > Here is an updated version of the patch, in which I added 1) an Assert
> > to ExecAR* functions to ensure that the passed-in ResultRelInfo
> > pointer is not NULL, 2) added/tweaked comments a bit more, and 3)
> > added regression tests.
>
> Thanks for the new patch.  LGTM.
>
> While reading it, I noticed that the functions performing table_open()
> are repeatedly called in this condition, which runs for every
> qualifying foreign child relations:
>
>         if (fdwroutine != NULL &&
>             fdwroutine->PlanDirectModify != NULL &&
>             fdwroutine->BeginDirectModify != NULL &&
>             fdwroutine->IterateDirectModify != NULL &&
>             fdwroutine->EndDirectModify != NULL &&
>             withCheckOptionLists == NIL &&
>             !has_row_triggers(root, rti, operation) &&
>             !has_stored_generated_columns(root, rti))
>
> That seems a bit expensive. It might be worth using *_valid flags to
> avoid redundant table_open() calls like you're doing for transition
> table checking. Maybe something to consider in a separate patch.


Ah, scratch that because I missed that transition table checking is done
for the “named” relation and these are checking it for child relations.

- Amit

>

  9. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Etsuro Fujita <etsuro.fujita@gmail.com> — 2025-07-14T11:00:15Z

    Amit-san,

On Thu, Jul 10, 2025 at 11:54 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Thu, Jul 10, 2025 at 22:20 Amit Langote <amitlangote09@gmail.com> wrote:
>> On Wed, Jul 9, 2025 at 5:07 PM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
>> > Here is an updated version of the patch, in which I added 1) an Assert
>> > to ExecAR* functions to ensure that the passed-in ResultRelInfo
>> > pointer is not NULL, 2) added/tweaked comments a bit more, and 3)
>> > added regression tests.
>>
>> Thanks for the new patch.  LGTM.

Cool!

>> While reading it, I noticed that the functions performing table_open()
>> are repeatedly called in this condition, which runs for every
>> qualifying foreign child relations:
>>
>>         if (fdwroutine != NULL &&
>>             fdwroutine->PlanDirectModify != NULL &&
>>             fdwroutine->BeginDirectModify != NULL &&
>>             fdwroutine->IterateDirectModify != NULL &&
>>             fdwroutine->EndDirectModify != NULL &&
>>             withCheckOptionLists == NIL &&
>>             !has_row_triggers(root, rti, operation) &&
>>             !has_stored_generated_columns(root, rti))
>>
>> That seems a bit expensive. It might be worth using *_valid flags to
>> avoid redundant table_open() calls like you're doing for transition
>> table checking. Maybe something to consider in a separate patch.

> Ah, scratch that because I missed that transition table checking is done for the “named” relation and these are checking it for child relations.

Ok, thanks for taking the time for this patch!

After re-reading the patch I noticed two minor things:

* The existing code in ExecAR* functions already dereferences the
passed-in ResultRelInfo pointer without checking that it is not NULL.
The Assert I added to those functions would be an overkill, so I
removed it.  Sorry for the back and forth.

* I added a trigger function trigger_nothing() in the regression
tests, but I noticed an existing trigger function above the tests.  To
make the tests a bit small, I replaced trigger_nothing() with the
existing trigger function and removed trigger_nothing().

Attached is a new version of the patch.

Best regards,
Etsuro Fujita

  10. Re: Problem with transition tables on partitioned tables with foreign-table partitions

    Etsuro Fujita <etsuro.fujita@gmail.com> — 2025-08-08T09:17:35Z

    On Mon, Jul 14, 2025 at 8:00 PM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> After re-reading the patch I noticed two minor things:
>
> * The existing code in ExecAR* functions already dereferences the
> passed-in ResultRelInfo pointer without checking that it is not NULL.
> The Assert I added to those functions would be an overkill, so I
> removed it.  Sorry for the back and forth.
>
> * I added a trigger function trigger_nothing() in the regression
> tests, but I noticed an existing trigger function above the tests.  To
> make the tests a bit small, I replaced trigger_nothing() with the
> existing trigger function and removed trigger_nothing().
>
> Attached is a new version of the patch.

I have pushed this and back-patched it to all supported versions.

Best regards,
Etsuro Fujita