Re: Inquiry About Determining Parallel Plans for REFRESH MATERIALIZED VIEW

On Thu, 16 Jan 2025 12:39:06 +0800
Zhang Mingli <zmlpostgres(at)gmail(dot)com> wrote:

> Hi, all
>
>
> I am currently exploring the execution of the REFRESH MATERIALIZED VIEW command  and have a specific question regarding the underlying query plan. As you know, the REFRESH command is a utility command, and using EXPLAIN REFRESH does not provide a plan structure for analysis.
>
> During development, we want to ascertain whether the SELECT part of the REFRESH command executes with a parallel plan. While I understand that we can run EXPLAIN on the SELECT statement directly, we are interested in knowing if there is a method to determine the execution plan under the REFRESH command context.
>
> Currently, we have configured the necessary settings for parallel queries and have been recording the execution time of the REFRESH command to compare parallel and non-parallel executions.
>
> However, I’m looking for a more definitive way to verify if the plan is indeed parallel during the execution of the REFRESH command.
>
> Any suggestions?

You will be able to log the plan during the REFRESH by using auto_explain and setting
log_analyze and log_nested_statements to on.

Regards,
Yugo Nagata

--
Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp>