Re: parallel data loading for pgbench -i

Hi Koshi,

On 02/10/2026 11:46, Koshi Shibagaki (Fujitsu) wrote:
> I did some additional testing of v4 and found three issues when parallel
> initialization is combined with range partitioning:

Thanks!

> One possible approach would be to use a scheme similar to v3: create the parent
> and child partitions in the t step, then have each worker TRUNCATE its assigned
> partition and run COPY ... WITH (FREEZE) on it in the same transaction during the g step.
Indeed, I went ahead and updated the patch following this approach. See
attached v5.
> 1. --tablespace is not applied to the standalone child partitions,
> so they are created in the database's default tablespace.
> 2. Running -I G after -I t fails because the t step does not create the child partitions.
> 3. Re-running -I g fails because createStandalonePartitions() attempts to
> create child tables that already exist.
>
> I reproduced issues 2 and 3 with the following commands, respectively:
>
>
> ```
> pgbench -i -I t -j 2 --partitions=4 --partition-method=range postgres
> pgbench -i -I G -j 2 --partitions=4 --partition-method=range postgres
> ```
>
> ```
> pgbench -i -I t -j 2 --partitions=4 --partition-method=range postgres
> pgbench -i -I g -j 2 --partitions=4 --partition-method=range postgres
> pgbench -i -I g -j 2 --partitions=4 --partition-method=range postgres

I've tried the above commands with v5 and confirm they are now working.

--
Thanks,
Mircea Cadariu