RE: Parallel Inserts in CREATE TABLE AS

From: Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>
> I think we can discuss this in a separate thread and see what other
> hackers think.

OK, unless we won't get stuck in the current direction. (Our goal is to not degrade in performance, but to outperform serial execution, isn't it?)

> If the idea is to give the user control of whether or not to use the
> separate RING BUFFER for bulk inserts/writes, then how about giving it
> as a rel option? Currently BAS_BULKWRITE (GetBulkInsertState), is
> being used by CTAS, Refresh Mat View, Table Rewrites (ATRewriteTable)
> and COPY. Furthermore, we could make the rel option an integer and
> allow users to provide the size of the ring buffer they want to choose
> for a particular bulk insert operation (of course with a max limit
> which is not exceeding the shared buffers or some reasonable amount
> not exceeding the RAM of the system).

I think it's not a table property but an execution property. So, it'd be appropriate to control it with the SET command, just like the DBA sets work_mem and maintenance_work_mem for specific maintenance operations.

I'll stop on this here...

Regards
Takayuki Tsunakawa