Hi,
On Dec 15, 2007 1:14 PM, Tom Lane <
tgl@sss.pgh.pa.us> wrote:
NikhilS <
nikkhils@gmail.com> writes:
> Any errors which occur before doing the heap_insert should not require
> any recovery according to me.
A sufficient (though far from all-encompassing) rejoinder to that is
"triggers and CHECK constraints can do anything".
> The overhead of having a subtransaction per row is a very valid concern. But
> instead of using a per insert or a batch insert substraction, I am
> thinking that we can start off a subtraction and continue it till we
> encounter a failure.The moment an error is encountered, since we have the offending >(already in heap) tuple around, we can call a simple_heap_delete on the same and commit >(instead of aborting) this subtransaction
What of failures that occur only at (sub)transaction commit, such as
foreign key checks?
What if we identify and define a subset where we could do subtransactions based COPY? The following could be supported:
* A subset of triggers and CHECK constraints which do not move the tuple around. (Identifying this subset might be an issue though?)
* Primary/unique key indexes
As Hannu mentioned elsewhere in this thread, there should not be very many instances of complex triggers/CHECKs around? And may be in those instances (and also the foreign key checks case), the behaviour could default to use a per-subtransaction-per-row or even the existing single transaction model?
Regards,
Nikhils
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