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Thread: vacuum full

vacuum full

From
Vijaykumar Jain
Date:
Just keeping it in a separate email, incase this is thrashed down.
vacuum full has a lot of problem stories, not just because the db gets locked, but also because it is mostly (mis)used when there are space issues.

of course, there are strong warnings in docs and wiki about using a vacuum full,
but i was just thinking 
vacuumdb and vacuumlo  can make use of options like --dry-run, like pg_repack allows,
but also just abort incase there is no disk space available.

i mean, i have seen confident replies from earlier mailing threads, where assume 2x disk required per object that is full vacuumed at least.

can this be converted into an estimate of sorts on objects that would be vacuumed and free disk that would be required before any operation starts.

maybe this is wishful thinking, but just asking.

--
Thanks,
Vijay
Mumbai, India

Re: vacuum full

From
Vijaykumar Jain
Date:
On Mon, 30 Aug 2021 at 23:12, Vijaykumar Jain <vijaykumarjain.github@gmail.com> wrote:
Just keeping it in a separate email, incase this is thrashed down.
vacuum full has a lot of problem stories, not just because the db gets locked, but also because it is mostly (mis)used when there are space issues.

 
ok ignore. 
I think querying the disk for available space may be shell access from the client, a security issue.
Also, a 10GB table with all dead tuples is 100% bloat, and would not really need additional space for table rebuilds.
I think we can just put out some queries like bloat estimation  of relations, to get an idea of wasted space and used space
and estimate based on that on how much would be taken up from the disk before being cleaned up.



 
--
Thanks,
Vijay
Mumbai, India

RE: vacuum full

From
Ian Dauncey
Date:

Morning.

 

Thanks for all the replies.

 

What I did to remove these files was to backup of the DB, drop the DB and then I restored the DB.

 

Regards

Ian

 

 

From: Vijaykumar Jain <vijaykumarjain.github@gmail.com>
Sent: Monday, 30 August 2021 20:06
To: pgsql-general <pgsql-general@lists.postgresql.org>
Subject: Re: vacuum full

 

External email - treat with caution

On Mon, 30 Aug 2021 at 23:12, Vijaykumar Jain <vijaykumarjain.github@gmail.com> wrote:

Just keeping it in a separate email, incase this is thrashed down.

vacuum full has a lot of problem stories, not just because the db gets locked, but also because it is mostly (mis)used when there are space issues.

 

 

ok ignore. 

I think querying the disk for available space may be shell access from the client, a security issue.

Also, a 10GB table with all dead tuples is 100% bloat, and would not really need additional space for table rebuilds.

I think we can just put out some queries like bloat estimation  of relations, to get an idea of wasted space and used space

and estimate based on that on how much would be taken up from the disk before being cleaned up.

 

 

 

 

--

Thanks,

Vijay

Mumbai, India



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