Re: [HACKERS] Parallel Hash take II - Mailing list pgsql-hackers

From Andres Freund
Subject Re: [HACKERS] Parallel Hash take II
Date
Msg-id 20171208000003.xlcfhvkdrr3gzu2x@alap3.anarazel.de
Whole thread Raw
In response to Re: [HACKERS] Parallel Hash take II  (Thomas Munro <thomas.munro@enterprisedb.com>)
Responses Re: [HACKERS] Parallel Hash take II
List pgsql-hackers
On 2017-12-08 12:07:04 +1300, Thomas Munro wrote:
> I suppose if we wanted to make this type of problem go away, but still
> keep files for forensic purposes, we could introduce a "restart
> number", and stick it into the top level temporary directory's name.
> That way you'd never be able to collide with files created before a
> crash-restart, and we could add O_EXCL so it'd become an error to try
> to create the same filename again.

I'm deeply unconvinced by the "forensic" argument to not do temp file
cleanup after crash restarts. That causes problems like the one we're
debating upthread in the first place, so I'm wholly unconvinced we
should add to that further by adding another layer of complexity.

My personal opinion is that we should just do temp file cleanup after
crash restarts, and document restart_after_crash = false as the solution
for investigating crashes.  I don't want to hold up this patch with a
discussion of that however, so I'm ok with your fix.

Greetings,

Andres Freund


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