maintenance_work_mem impact? - Mailing list pgsql-performance

From Adithya Kumaranchath
Subject maintenance_work_mem impact?
Date
Msg-id AM9P193MB179351C6F5F83B34C71E04C3DB2C2@AM9P193MB1793.EURP193.PROD.OUTLOOK.COM
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Responses Re: maintenance_work_mem impact?
List pgsql-performance
Hi all,

I have a table approx. 20GB.

I have a create unique index statement.

CREATE UNIQUE INDEX testindex_v1 ON testtable1 (test_index); 

My observations:
maintenance_work_mem = 2G
max_parallel_workers = '16'

The create index completes in 20 minutes.

When I change this:
maintenance_work_mem = 16G
max_parallel_workers = '16'

It completes in 9 minutes. So I can see that I can gain performance by changing this number.

So it is faster but the question I have is it safe to set it to such a high number? I am aware that only one of these operations can be executed at a time by a database session, and an installation normally doesn't have many of them running concurrently, so it's safe to set this value significantly larger. I have 128GB memory.

  1. Any advice or thoughts?
  2. Is there any other parameter that can accelerate index creation? 

Thanks,
Ad

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