V4WS need to use semaphores when READ from table in case cause simultaneous indexing?

[Ruslan Zasukhin]

On 11/25/04 11:32 PM, "Steven" <srt at bigpond.net.au> wrote:

Hi Steven,

You think in too complex way.

You use db.SqlSelect() and db.SqlExecute(), right?
You get cursor in the firs case.
Valentina self will lock records using options you provide.
Each thread/page have own cursor.
Each cursor can read or write records independently, because each cursor
lock own records.

So actually I do not see reasons why you need to use in V4WS semaphores.

Do you have any problems IF you not use them?


>> Use semaphore also for safe.
>> 
>> But taking into account that OS 9 is cooperative.
>> Exists chance that you can avoid this step.
>> You can self test if it works.
> 
> Ruslan,
> 
> are you saying that the only time I can allow simultaneous access to a
> table is if there will be no change in the index of the table as a result
> of allowing access?! Then if any action (add record, update, even READ!)
> can cause the index to be modified I must only allow one user at a time
> access to the table??? Before I thought I just had to take care to do
> "record locking" (approximated in OS 9 by using semaphores labelled for the
> record in question) - now you seem to be saying I need to do "table
> locking" because the index might get messed up if there are simultaneous
> requests to update it?
> 
> Is this just a problem for the OS 9 version (subject to testing) or is this
> true for all platforms? It seems a limitation to me since you can't have
> simulataneous access to a table except when you are not doing anything that
> can change the index?
> 
> Specifically, will this be a problem for OS X when eventually we have
> WebSiphon 3/V4WS for OS X? If so then I need to fix code now regardless of
> whether it is safe in OS 9 or not.

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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