Yes, MaxDB keeps some row locks on  SELECTs (these 'row_share' locks you may see in 
LOCKSTATISTICS) 
if the isolation level requires it. 

Simply speaking, if you want a 'read committed' isolation, you must 
prevent another session from updating a row if you have accesssed it, cause you might 
want to
read it again (this is an over-simplification). 

However, how did you produce that selects for the trace files? My colleguages insist 
that TRANSID is a hex value and can never have a value  'LOB' ...


Alexander Schr�der
SAP DB, SAP Labs Berlin 

> -----Original Message-----
> From: Andre Reitz [mailto:[EMAIL PROTECTED]
> Sent: Monday, February 23, 2004 11:44 AM
> To: Schroeder, Alexander
> Subject: Re: DEADLOCKS Caused by SELECTS
> 
> 
> On Mon, 23 Feb 2004 11:29:47 +0100
> "Schroeder, Alexander" <[EMAIL PROTECTED]> wrote:
> 
> > Hello Andre,
> > > We have a serious problem with sapdb version 7.4.3.31 (on 
> SuSE-Linux)
> > > - We have clients with long running transactions, all with 
> > > isolationlevel 1.
> > > - Many of them do many SELECTS without commit.
> > > - These SELECTS sometimes keep Locks, which block other 
> > >   clients when they
> > >   trying to write on those tables.
> > 
> > It would be useful going a little into detail here, e.g. 
> describing what kind are your SELECTs,
> > what are the commands that are blocked and hang, and what 
> is the content of LOCKSTATISTICS at 
> > that time.
> > 
> 
> Lockstatistics: (3 different versions)
> See attachment.
> 
> 
> We have around 40 Tables which are linked to each other by 
> many foreign keys.
> The SELECTS use very often joins and outher joins.
> 
> 
> By the way:
>  Is it possible that sapdb keeps a row lock when a transaction is only
>  doing SELECTS in ISOLATIONLEVEL 1?
> 
> 
> 
> 
> 
> Greetings, Andre'
> 
> 
> 
> > > - I was told, that these behaviour was a bug of version 7.3, 
> > >   and that I should upgrade to 7.4.
> > 
> > Those problems made your issues probably only much more 
> worse, and showed up first. 
> > 
> > > - It seems that the problem still exists.
> > 
> > I think the problem has the same symptoms, but is not 
> necessarily the same ... so please
> > send a little more information.
> > 
> > Regards
> > Alexander Schr�der
> > SAP DB, SAP Labs Berlin
> > 
> 
> 
> -- 
> ______________________________________________________________
> ____________
> 
> Als Technologieunternehmen konzipieren und entwickeln wir 
> ma�geschneiderte Feedback- und
> Monitoring-Systeme - wie beispielsweise L�sungen f�r 
> Beschwerde- und Ideenmanagement.
> Mit dem Inquery� Survey Server bieten wir eine der 
> leistungsf�higsten Standardl�sungen f�r
> Online-Umfragen mit dem Schwerpunkt auf der Messung von 
> Kundenzufriedenheit an.
> ______________________________________________________________
> ____________
> 
> 
> Inworks GmbH
> Andre Reitz, Leiter Entwicklung
> H�rvelsinger Weg 39, 89081 Ulm, Germany
> Tel +49 (0) 731 / 93807-21
> Fax +49(0)731/93807-18
> Internet: http://www.inworks.de
> 
> 
> 

--
MaxDB Discussion Mailing List
For list archives: http://lists.mysql.com/maxdb
To unsubscribe:    http://lists.mysql.com/[EMAIL PROTECTED]

Reply via email to