You can tell how many clients are connected to a table in a 3.30 application
in local network , without using DBSRVR ?
The maximum number to be tested is less than 20 clients.

Thanks

Carlos

Carlos

>You can tell how many clients are connected to a table in a 3.30 application
>in local network , without using DBSRVR ?

Only if you manage it yourself. There's nothing in fileserver mode that can give you the information.

Roy Lambert [Team Elevate]

"Carlos" <carlos@noemail.com> wrote in message
news:6FDE2C71-3319-43F6-8E8F-6F0B4E334B2B@news.elevatesoft.com...
> You can tell how many clients are connected to a table in a 3.30
> application in local network , without using DBSRVR ?
> The maximum number to be tested is less than 20 clients.


You have to code it yourslf, but it is pretty easy. Using semaphores, you
add a semaphore every time a user is connected, and delete the sempahore
when they log out. Sempahores are cleaned up automatically if the app
crashes, so there will be no garbage left over.

To count number of users, you attempt to place semaphores form 1 to 20,
every time you fail it is because there is an active user.

If you want to do it, post again and I'll give you a couple of code
examples.

>
> Thanks
>
> Carlos
>
>

"Robert" <ngsemail2005withoutthis@yahoo.com.ar> ha scritto nel messaggio
news:CFD719B9-6236-4AA4-AB54-9F080E4DDC62@news.elevatesoft.com...
>
> "Carlos" <carlos@noemail.com> wrote in message
> news:6FDE2C71-3319-43F6-8E8F-6F0B4E334B2B@news.elevatesoft.com...
>> You can tell how many clients are connected to a table in a 3.30
>> application in local network , without using DBSRVR ?
>> The maximum number to be tested is less than 20 clients.
>
>
> You have to code it yourslf, but it is pretty easy. Using semaphores, you
> add a semaphore every time a user is connected, and delete the sempahore
> when they log out. Sempahores are cleaned up automatically if the app
> crashes, so there will be no garbage left over.
>
> To count number of users, you attempt to place semaphores form 1 to 20,
> every time you fail it is because there is an active user.
>
> If you want to do it, post again and I'll give you a couple of code
> examples.
>
>>
>> Thanks
>>
>> Carlos
>>
>>
>
>

I write this snippet of code to active and count the semaphore
The test for the latest clinet is a bit slow.


procedure TForm1.SemaphoreClick(Sender: TObject);
Var
 i: integer;
begin
 DBISAMSession1.LockWaitTime:=1;
 DBISAMSession1.LockRetryCount:=1;

 for i:=1 to 20 do begin
     if UTENTI.LOCKSEMAPHORE(I) then break;
 end;

 DBISAMSession1.LockRetryCount:=15;
 DBISAMSession1.LockWaitTime:=100;

 Memo1.Lines.Add(intToStr(i));
end;

"Carlos" <carlos@noemail.com> wrote in message
news:E0655F81-65BB-4C7F-9DAA-4551A8E8C607@news.elevatesoft.com...
>
>>
>
> I write this snippet of code to active and count the semaphore
> The test for the latest clinet is a bit slow.
>

I'm not sure what "a bit slow" is, but I just run your code (similar,
anyway) putting 20 sempahores on a table, and it is instantaneous. Are you
sure you are modifying the right session for the wait time and retry count?
I set 20 semaphores, and then looped trying to set them again (basically
going thru the wait time for each one) and both operations were
instantaneous.

Keep in mind that you will have to reset the semaphores you don't want, as
in the code below.

function CountActiveUsers : integer;
var i : integer;
begin
// modify session
 result := 0;
 for i := 1 to 20 do
  if Table.LockSempahore(i) then Table.UnlockSemaphore(i) else inc(Result);
 // reset session
end;

Robert

>
> procedure TForm1.SemaphoreClick(Sender: TObject);
> Var
>  i: integer;
> begin
>  DBISAMSession1.LockWaitTime:=1;
>  DBISAMSession1.LockRetryCount:=1;
>
>  for i:=1 to 20 do begin
>      if UTENTI.LOCKSEMAPHORE(I) then break;
>  end;
>
>  DBISAMSession1.LockRetryCount:=15;
>  DBISAMSession1.LockWaitTime:=100;
>
>  Memo1.Lines.Add(intToStr(i));
> end;
>
>
>

I wish Tim would add this or more specifically, an "official" way to tell
how many people were logged into DBISAM and a way to set a limit to the
connections.  It seems this question is asked relatively frequently and the
answer is always "It is easy.  Do this."

Plus with the paid support plans, it would be an easy way to add a feature.
(wink, wink)




On 2/20/09 9:27 AM, in article
CFD719B9-6236-4AA4-AB54-9F080E4DDC62@news.elevatesoft.com, "Robert"
<ngsemail2005withoutthis@yahoo.com.ar> wrote:

>
> "Carlos" <carlos@noemail.com> wrote in message
> news:6FDE2C71-3319-43F6-8E8F-6F0B4E334B2B@news.elevatesoft.com...
>> You can tell how many clients are connected to a table in a 3.30
>> application in local network , without using DBSRVR ?
>> The maximum number to be tested is less than 20 clients.
>
>
> You have to code it yourslf, but it is pretty easy. Using semaphores, you
> add a semaphore every time a user is connected, and delete the sempahore
> when they log out. Sempahores are cleaned up automatically if the app
> crashes, so there will be no garbage left over.
>
> To count number of users, you attempt to place semaphores form 1 to 20,
> every time you fail it is because there is an active user.
>
> If you want to do it, post again and I'll give you a couple of code
> examples.
>
>>
>> Thanks
>>
>> Carlos
>>
>>
>
>

David,

<< I wish Tim would add this or more specifically, an "official" way to tell
how many people were logged into DBISAM and a way to set a limit to the
connections.  It seems this question is asked relatively frequently and the
answer is always "It is easy.  Do this." >>

I did add this - in ElevateDB.

I'd have to look into whether this is possible in DBISAM or not.  There are
some specific things about ElevateDB that allow it to uniquely track
sessions so as to get an accurate count and not see duplicates.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim

><< I wish Tim would add this or more specifically, an "official" way to tell
>how many people were logged into DBISAM and a way to set a limit to the
>connections. It seems this question is asked relatively frequently and the
> answer is always "It is easy. Do this." >>
>
>I did add this - in ElevateDB.

I thought that was only c/s not f/s

Roy Lambert

Roy,

<< I thought that was only c/s not f/s >>

No, it's both.  The only thing missing (that will be available in 2.03) is
the bit about excluding certain sessions from the count.  We need for the
job execution session in the server, and developers need it for threaded
background access from their application.

--
Tim Young
Elevate Software
www.elevatesoft.com