Re: [POC] Fast COPY FROM command for the table with foreign partitions

On 6/22/20 5:11 PM, Ashutosh Bapat wrote:

> <a.lepikhov@postgrespro.ru <mailto:a.lepikhov@postgrespro.ru>> wrote:
> It looks like we call BeginForeignInsert and EndForeignInsert even 
> though actual copy is performed using BeginForeignCopy, ExecForeignCopy 
> and EndForeignCopy. BeginForeignInsert constructs the INSERT query which 
> looks unnecessary. Also some of the other PgFdwModifyState members are 
> initialized unnecessarily. It also gives an impression that we are using 
> INSERT underneath the copy. Instead a better way would be to 
> call BeginForeignCopy instead of BeginForeignInsert and EndForeignCopy 
> instead of EndForeignInsert, if we are going to use COPY protocol to 
> copy data to the foreign server. Corresponding postgres_fdw 
> implementations need to change in order to do that.
> 
I did not answer for a long time, because of waiting for the results of 
the discussion on Tomas approach to bulk INSERT/UPDATE/DELETE. It seems 
more general.
I can move the query construction into the first execution of INSERT or 
COPY operation. But another changes seems more invasive because 
BeginForeignInsert/EndForeignInsert are used in the execPartition.c 
module. We will need to pass copy/insert state of operation into 
ExecFindPartition() and ExecCleanupTupleRouting().

-- 
regards,
Andrey Lepikhov
Postgres Professional