[DUG] List working?

Thu Mar 16 16:18:00 NZDT 2006

Which is exactly the effect of having multiple threads which are not
thread safe.

> QUOTE FROM
>
> http://support.microsoft.com/?scid=kb;en-us;303528
>
> Additional best practices for network environments
>
> Microsoft Jet is a file-sharing database system. A file-sharing database
> system means that the processing of the file occurs at the client. When a
> file-sharing database, such as Microsoft Jet, is used in a multi-user
> environment, multiple client processes use file read, file write, and file
> locking operations on the same shared file across a network. If a process
> cannot be completed, the file may be left in an incomplete state or in a
> corrupted state. A process may not be completed for either of the
> following
> reasons:
>
>
> .
>
> When a client is stopped unexpectedly
>
>
> .
>
> When a network connection to a server is dropped
>
> Microsoft Jet is not intended for use with high-stress server
> applications,
> high-concurrency server applications, or 24 hours a day, seven days a week
> server applications. This includes server applications, such as Web
> applications, commerce applications, transactional applications, and
> messaging server applications. For these types of applications, the best
> solution is to switch to a true client/server-based database system, such
> as
> Microsoft Data Engine (MSDE) or Microsoft SQL Server. When you use
> Microsoft
> Jet in high-stress applications such as Microsoft Internet Information
> Server (IIS), you may experience any one of the following problems:
>
>
> .
>
> Database corruption
>
>
> .
>
> Stability issues, such as IIS crashing or locking up
>
>
> .
>
> Sudden failure or persistent failure of the driver to connect to a valid
> database that requires re-starting the IIS service
>
> The following sections contain recommendations to follow when you share a
> Microsoft Jet or a Microsoft Access database file on a network file
> server.
>
>
>
> -----Original Message-----
> From: delphi-bounces at ns3.123.co.nz [mailto:delphi-bounces at ns3.123.co.nz]
> On
> Behalf Of Matthew Comb
> Sent: Thursday, 16 March 2006 4:09 p.m.
> To: NZ Borland Developers Group - Delphi List
> Subject: RE: [DUG] List working?
>
>
>
> I've always felt like Access was like a multithreaded server without
>
> critical sections.
>
>
>
> With one user you will have absolutely no problems. With few users its
>
> highly unlikely that the threads will clash.
>
>
>
> With more users, it turns to a pile of crap, which can be addressed by
>
> having keepalives (rebuild mechanisms on startups and around the posting
>
> routines etc).
>
>
>
> But seriously. I can't accept that people would actually push access as a
>
> serious contender for multi user environments.
>
>
>
> I mean sure I could wash my clothes in the bath, but it doesn't make it a
>
> dual purpose washing machine,
>
>
>
> and if i was going to  ride up a mountain, I could surely do it on a bike,
>
> but it would be a hell of a lot easier in a 4 wheel drive. Especially one
>
> strong enough to protect me from crazy random people on bikes descending
>
> down the mountain...
>
>
>
>
>
>
>
>> Well if we are talking a small multiuser system then it does have some
>
>> advantages. In my view those advantages are more than outweighed by the
>
>> potential for data corruption anytime a client freezes or disconnects
>> from
>
>> the network, not to mention lack of Stored Procs etc (at least in the
>
>> version I used). That's why we use MSDE/SQL Server instead now.
>
>>
>
>> However that doesn't mean everyone would come to the same conclusion I
>
>> did.
>
>> For some people Access's advantages might be godsends. For example, I
>> have
>
>> my doubts that our Christchurch customer is using the same server box
>> that
>
>> they were using 8 years ago (they might be but it seems unlikely). That
>
>> means they have probably moved the database on their own without
>> support.
>
>> With Access moving the database just means moving the mdb file and
>
>> creating
>
>> a new network share. I doubt they would have been able to move an MSDE
>
>> database without our help. Similarly backing up MSDE requires either
>
>> special
>
>> backup software or running a script to backup the data/log files to disk
>
>> and
>
>> then to your backup destination. Backing up Access is a simple matter of
>
>> copying a file.
>
>>
>
>> Access is also blindingly fast at accessing data which isn't changing.
>
>> Once
>
>> data has been cached locally it becomes near impossible for a proper
>
>> server
>
>> based database to compete in pure read speed terms. Of course if the
>> data
>
>> being accessed is constantly changing then the situation reverses, etc.
>
>>
>
>> Just because most serious developers value the functionality of a server
>
>> based database more than the functionality Access provides doesn't mean
>
>> that
>
>> it is a completely useless product.
>
>>
>
>> All IMO of course. And should be taken with a grain of salt as I haven't
>
>> used Access for development since 1998...
>
>>
>
>> David.
>
>>
>
>>
>
>>
>
>> -----Original Message-----
>
>> From: delphi-bounces at ns3.123.co.nz [mailto:delphi-bounces at ns3.123.co.nz]
>
>> On
>
>> Behalf Of Neven MacEwan
>
>> Sent: Thursday, 16 March 2006 3:45 p.m.
>
>> To: NZ Borland Developers Group - Delphi List
>
>> Subject: Re: [DUG] List working?
>
>>
>
>> David
>
>>
>
>> In my opinion a software product that doesn't meet very high reliability
>
>>   levels in its designers intended use is a poor product, If you are
>
>> prepared to state that Access is a very reliable platform in multiuser
>
>> environments I'd be interested, otherwise you might as well suggest a
>
>> person with a stutter makes a very good news reader providing you listen
>
>> carefully
>
>>
>
>> Neven
>
>>
>
>> David Brennan wrote:
>
>>> We have a customer in Christchurch who has been running an old VB4
>
>>> version
>
>>> of our software with multiple client machines connecting to an Access
>
>>> 2.0
>
>>> (32 bit) database. They have been running the software for about 7 or 8
>
>>> years.
>
>>>
>
>>> We tend to forget they are there... because they have never once called
>
>> with
>
>>> a problem of any sort.
>
>>>
>
>>> Not saying you are going to be that lucky every time and part of the
>
>> reason
>
>>> we don't hear from them may be that the program has startup code for
>
>>> attempting auto-recovery from corrupted databases. But Access <can> be
>
>>> surprisingly fast and reliable.
>
>>>
>
>>> David.
>
>>>
>
>>>
>
>>> -----Original Message-----
>
>>> From: delphi-bounces at ns3.123.co.nz
>>> [mailto:delphi-bounces at ns3.123.co.nz]
>
>> On
>
>>> Behalf Of Neven MacEwan
>
>>> Sent: Thursday, 16 March 2006 3:16 p.m.
>
>>> To: NZ Borland Developers Group - Delphi List
>
>>> Subject: Re: [DUG] List working?
>
>>>
>
>>> Don't be dim James are you saying that Access is not intended for DB
>
>>> applications, The assertion that its ok  and was designed for "single
>
>>> user desktop style" apps and not anything more is crap if it wasn't
>
>>> intended for " multi user environment" then it shouldn'd effing well
>
>>> support it (badly or otherwise) should it?
>
>>>
>
>>> Neven
>
>>>
>
>>> James Sugrue wrote:
>
>>>> The problem isn't with Access, the problem is people using Access for
>
>>> things
>
>>>> it's not really intended for.
>
>>>> Access is fine - and I use it all the time - for single user desktop
>
>> style
>
>>>> applications. It's when it gets used in a multi user environment
>>>> things
>
>>> can
>
>>>> be a problem, especially when combined with bad design or programming.
>
>>>>
>
>>>>
>
>>>> -----Original Message-----
>
>>>> From: delphi-bounces at ns3.123.co.nz
>
>>>> [mailto:delphi-bounces at ns3.123.co.nz]
>
>>> On
>
>>>> Behalf Of Maurice Butler
>
>>>> Sent: Thursday, 16 March 2006 8:28 a.m.
>
>>>> To: 'NZ Borland Developers Group - Delphi List'
>
>>>> Subject: RE: [DUG] List working?
>
>>>>
>
>>>> Hi,
>
>>>> If you want to know how bad Mickysoft Access is ask any school that
>
>>>> runs
>
>>>> musac - this is a student manager program that spends more time being
>
>>> fixed
>
>>>> than used.
>
>>>> If you want sql, mdse is alright for small apps that need sql &
>
>>>> Mickysoft
>
>>>> compatablity.
>
>>>>
>
>>>> Maurice
>
>>>>
>
>>>>
>
>>>>
>
>>>> _______________________________________________
>
>>>> Delphi mailing list
>
>>>> Delphi at ns3.123.co.nz
>
>>>> http://ns3.123.co.nz/mailman/listinfo/delphi
>
>>>>
>
>>>>
>
>>>
>
>>
>
>> --
>
>> Neven MacEwan (B.E. E&E)
>
>> Ph. 09 620 1356 Mob. 027 4749 062
>
>>
>
>> New Address Details
>
>> ===================
>
>> MWK Computer Systems
>
>> 1 Taumata Rd
>
>> Sandringham
>
>> Auckland
>
>>
>
>> Ph 620 1356
>
>> Fx 620 1336
>
>>
>
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>
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>
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>
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>
>>
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>
>
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