Re: [HACKERS] Index bloat problem in 7.4

2006-09-22 Thread Alvaro Herrera
Dave Cramer wrote:
> 
> On 22-Sep-06, at 3:58 AM, Markus Schaber wrote:
> 
> >Hi, Alvaro,
> >
> >Alvaro Herrera wrote:
> >
> I am aware that more recent versions > 8.x have fixed this  
> problem, I
> checked the 7.4 release notes but can't see if any of the fixes  
> made it
> into 7.4.
> >>>Usually, only critical data loss and security fixes are put into the
> >>>minor updates (e. G. 7.4.0 to 7.4.13). So, if it's not in the  
> >>>release
> >>>notes, it is unlikely that it dit make it into the 7.4 releases.
> >>Except it was solved in 7.4:
> >>
> >>Allow B-tree index compaction and empty page reuse (Tom)
> >
> >Yes, you're right, the change is listed on
> >http://www.postgresql.org/docs/7.4/interactive/release-7-4.html
> >
> >So, as it _is_ in the release notes, this does not render my statement
> >wrong, but pointless :-)
> 
> My understanding is that further work was done to address this in  
> later versions as well.
> 
> My client is experiencing index bloat in 7.4.x.

My guess is that they will still experience it even with 8.2, because
the situations on which the problem keeps happening have not, to my
knowledge, been addressed in later versions.

The main problem remaining is that partially filled paged are not
merged, so if you delete multiple old tuples (say, indexed by a
timestamp or a monotonously increasing key) and replace it with a single
"summary" tuple keyed with a value in the same range, the index page
where that tuple is stored will likely not contain a lot of other index
entries.

-- 
Alvaro Herrerahttp://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

---(end of broadcast)---
TIP 5: don't forget to increase your free space map settings


Re: [HACKERS] Index bloat problem in 7.4

2006-09-22 Thread Dave Cramer


On 22-Sep-06, at 3:58 AM, Markus Schaber wrote:


Hi, Alvaro,

Alvaro Herrera wrote:

I am aware that more recent versions > 8.x have fixed this  
problem, I
checked the 7.4 release notes but can't see if any of the fixes  
made it

into 7.4.

Usually, only critical data loss and security fixes are put into the
minor updates (e. G. 7.4.0 to 7.4.13). So, if it's not in the  
release

notes, it is unlikely that it dit make it into the 7.4 releases.

Except it was solved in 7.4:

Allow B-tree index compaction and empty page reuse (Tom)


Yes, you're right, the change is listed on
http://www.postgresql.org/docs/7.4/interactive/release-7-4.html

So, as it _is_ in the release notes, this does not render my statement
wrong, but pointless :-)


My understanding is that further work was done to address this in  
later versions as well.


My client is experiencing index bloat in 7.4.x.

Dave


Thanks for your correction,
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS

Fight against software patents in Europe! www.ffii.org
www.nosoftwarepatents.org




---(end of broadcast)---
TIP 1: if posting/reading through Usenet, please send an appropriate
  subscribe-nomail command to [EMAIL PROTECTED] so that your
  message can get through to the mailing list cleanly


Re: [HACKERS] Index bloat problem in 7.4

2006-09-22 Thread Markus Schaber
Hi, Alvaro,

Alvaro Herrera wrote:

>>> I am aware that more recent versions > 8.x have fixed this problem, I
>>> checked the 7.4 release notes but can't see if any of the fixes made it
>>> into 7.4.
>> Usually, only critical data loss and security fixes are put into the
>> minor updates (e. G. 7.4.0 to 7.4.13). So, if it's not in the release
>> notes, it is unlikely that it dit make it into the 7.4 releases.
> Except it was solved in 7.4:
> 
> Allow B-tree index compaction and empty page reuse (Tom)

Yes, you're right, the change is listed on
http://www.postgresql.org/docs/7.4/interactive/release-7-4.html

So, as it _is_ in the release notes, this does not render my statement
wrong, but pointless :-)

Thanks for your correction,
Markus
-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS

Fight against software patents in Europe! www.ffii.org
www.nosoftwarepatents.org



signature.asc
Description: OpenPGP digital signature


Re: [HACKERS] Index bloat problem in 7.4

2006-09-21 Thread Alvaro Herrera
Markus Schaber wrote:
> Hi, Dave,
> 
> Dave Cramer wrote:
> > I am aware that more recent versions > 8.x have fixed this problem, I
> > checked the 7.4 release notes but can't see if any of the fixes made it
> > into 7.4.
> 
> Usually, only critical data loss and security fixes are put into the
> minor updates (e. G. 7.4.0 to 7.4.13). So, if it's not in the release
> notes, it is unlikely that it dit make it into the 7.4 releases.

Except it was solved in 7.4:

Allow B-tree index compaction and empty page reuse (Tom)

-- 
Alvaro Herrerahttp://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

---(end of broadcast)---
TIP 2: Don't 'kill -9' the postmaster


Re: [HACKERS] Index bloat problem in 7.4

2006-09-21 Thread Markus Schaber
Hi, Dave,

Dave Cramer wrote:
> I am aware that more recent versions > 8.x have fixed this problem, I
> checked the 7.4 release notes but can't see if any of the fixes made it
> into 7.4.

Usually, only critical data loss and security fixes are put into the
minor updates (e. G. 7.4.0 to 7.4.13). So, if it's not in the release
notes, it is unlikely that it dit make it into the 7.4 releases.

You may try backporting it yourself, or use a cronjob or such issuing
regular REINDEX commands during the night (or whenever you have idle hours).

HTH;
Markus

-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS

Fight against software patents in Europe! www.ffii.org
www.nosoftwarepatents.org



signature.asc
Description: OpenPGP digital signature