RE: POC: postgres_fdw insert batching

Tomas-san,

From: Amit Langote <amitlangote09(at)gmail(dot)com>
> Good thing you reminded me that this is about inserts, and in that
> case no, ExecInitModifyTable() doesn't know all leaf partitions, it
> only sees the root table whose batch_size doesn't really matter. So
> it's really ExecInitRoutingInfo() that I would recommend to set
> ri_BatchSize; right after this block:
>
> /*
> * If the partition is a foreign table, let the FDW init itself for
> * routing tuples to the partition.
> */
> if (partRelInfo->ri_FdwRoutine != NULL &&
> partRelInfo->ri_FdwRoutine->BeginForeignInsert != NULL)
> partRelInfo->ri_FdwRoutine->BeginForeignInsert(mtstate, partRelInfo);
>
> Note that ExecInitRoutingInfo() is called only once for a partition
> when it is initialized after being inserted into for the first time.
>
> For a non-partitioned targets, I'd still say set ri_BatchSize in
> ExecInitModifyTable().

Attached is the patch that added call to GetModifyBatchSize() to the above two places. The regression test passes.

(FWIW, frankly, I prefer the previous version because the code is a bit smaller... Maybe we should refactor the code someday to reduce similar processings in both the partitioned case and non-partitioned case.)

Regards
Takayuki Tsunakawa