Hi Luis and Amit,
Thanks for the report, Luis! Thanks for the discussion, Amit!
(2018/12/18 12:24), Amit Langote wrote:
> On 2018/12/17 22:12, Luis Carril wrote:
>>> heap_sync should only be called for relations that actually have files to
>>> sync, which isn't true for foreign tables. So, a simple relkind check
>>> before calling heap_sync() in CopyFrom would suffice I think. Although,
>>> we might also need such a check higher up in CopyFrom where some
>>> optimizations that are specific to "heap" relations are enabled. For
>>> example, this piece of code:
>>
>> thanks for the input, so it seems that is enough with adding the check as you suggested:
>>
>> if (cstate->rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE&&
>> cstate->rel->rd_rel->relkind != RELKIND_FOREIGN_TABLE&&
>> (cstate->rel->rd_createSubid != InvalidSubTransactionId ||
>> cstate->rel->rd_newRelfilenodeSubid != InvalidSubTransactionId))
>> {
>> hi_options |= HEAP_INSERT_SKIP_FSM;
>> if (!XLogIsNeeded())
>> hi_options |= HEAP_INSERT_SKIP_WAL;
>> }
>
> I think that would do the trick.
I think so too.
FDWs would not look at heap_insert options, so another option would be
to 1) leave that options as-is for foreign tables and 2) if the target
is a foreign table, just skip heap_sync at the bottom of CopyFrom, or
just return without doing anything in heap_sync.
Best regards,
Etsuro Fujita