Re: Possible race condition in pg_mkdir_p()? - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Possible race condition in pg_mkdir_p()?
Date
Msg-id 20190731041144.gkmfpvgqa2otl3kp@alap3.anarazel.de
Whole thread Raw
In response to Possible race condition in pg_mkdir_p()?  (Ning Yu <nyu@pivotal.io>)
Responses Re: Possible race condition in pg_mkdir_p()?  (Ning Yu <nyu@pivotal.io>)
Re: Possible race condition in pg_mkdir_p()?  (Michael Paquier <michael@paquier.xyz>)
List pgsql-hackers
Hi,

On 2019-07-18 16:17:22 +0800, Ning Yu wrote:
> This seems buggy as it first checks the existence of the dir and makes the
> dir if it does not exist yet, however when executing concurrently a
> possible race condition can be as below:
> 
> A: does a/ exists? no
> B: does a/ exists? no
> A: try to create a/, succeed
> B: try to create a/, failed as it already exists

Hm. I'm not really seing much of a point in making mkdir_p safe against
all of this. What's the scenario for pg where this matters? I assume
you're using it for somewhat different purposes, and that's why it is
problematic for you?

Greetings,

Andres Freund



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