Skip site navigation (1) Skip section navigation (2)

Re: VACUUM and open transactions

From: Joseph S <jks(at)selectacast(dot)net>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: VACUUM and open transactions
Date: 2007-01-31 02:15:52
Message-ID: 45BFFBD8.8060908@selectacast.net (view raw or flat)
Thread:
Lists: pgsql-general
The serializable transaction  *can't* see those rows, they were created 
and obsoleted after the start of the transaction.  The point of make the 
transaction serializable in the first place was to allow VACUUM to 
reclaim those rows.

Alvaro Herrera wrote:
> Joseph S wrote:
>> I realize this thread is old, but I just conducted an experiment with pg 
>> 8.0.10 and a transaction with a SERIALIZABLE isolation level does 
>> prevent VACUUM from reclaiming rows that were created and then obsoleted 
>>  in a subsequent transaction.
> 
> Right.  This is expected.  VACUUM cannot remove them because the
> serializable transaction might still want to see those rows.  (I am
> assuming the serializable transaction is still running when the vacuum
> starts.  If that's not the case, please explain better).
> 


In response to

Responses

pgsql-general by date

Next:From: Alvaro HerreraDate: 2007-01-31 02:27:03
Subject: Re: VACUUM and open transactions
Previous:From: Joshua D. DrakeDate: 2007-01-31 02:15:01
Subject: Re: Any Plans for cross database queries on the same server?

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group