Class used by multiple threads to write to Table

3 Jul 2006 9:02 PM

cj

I want to make a class that will write data to a in memory table. This
class will be called by multiple threads. I'm hoping the table can stay
in memory between calls and all the call by the thread will have to do
is pass some data to be added to the table. Kinda like this class I
have to write to a log file.

Public Class MyStringLogger
     Private Shared m_loglock As New Object

     Public Shared Sub Write(ByVal fileName As String, ByVal strToWrite
As String)
         SyncLock (m_loglock)
             Try
                 Dim sw As New System.io.StreamWriter(fileName, True)
                 sw.WriteLine(strToWrite)
                 sw.Close()
             Catch
             End Try
         End SyncLock
     End Sub
End Class

Any idea how I'd do this?

4 Jul 2006 4:31 AM

Cor Ligthert [MVP]

cj,

Are you sure that you don't need the queue class which is very standard for
this?

http://msdn2.microsoft.com/en-us/library/ms287330.aspx

I hope this helps,

Cor

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"cj" <cj@nospam.nospam> schreef in bericht
news:OenEEPunGHA.4892@TK2MSFTNGP03.phx.gbl...
>I want to make a class that will write data to a in memory table. This
>class will be called by multiple threads. I'm hoping the table can stay in
>memory between calls and all the call by the thread will have to do is pass
>some data to be added to the table. Kinda like this class I have to write
>to a log file.
>
> Public Class MyStringLogger
>     Private Shared m_loglock As New Object
>
>     Public Shared Sub Write(ByVal fileName As String, ByVal strToWrite As
> String)
>         SyncLock (m_loglock)
>             Try
>                 Dim sw As New System.io.StreamWriter(fileName, True)
>                 sw.WriteLine(strToWrite)
>                 sw.Close()
>             Catch
>             End Try
>         End SyncLock
>     End Sub
> End Class
>
> Any idea how I'd do this?

4 Jul 2006 10:14 AM

Jeffrey Tan[MSFT]

Hi Cj,

It seems Cor Ligthert [MVP] provided an incorrect URL for queue class, I
think he is referring the URL below:
"Queue Class"
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/
frlrfsystemcollectionsqueueclasstopic.asp

There are several container classes in .Net may fit your need, such as
ArrayList, Hashtable, Queue etc..., they all exist under System.Collections
namespace. They all have different usages, you may refer to MSDN for their
difference and choose the suitable for using as memory container table.

Hope this helps!

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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4 Jul 2006 11:22 AM

Cor Ligthert [MVP]

Jeffrey,

Thank you, I did not copy it this was from a previous answer, mine was

http://msdn2.microsoft.com/en-us/library/system.collections.queue.aspx

A little bit shorter than your URL.

By the way, the queue class (FIFO) is extremely sufficient with multi
threading.

Cor

""Jeffrey Tan[MSFT]"" <je***@online.microsoft.com> schreef in bericht
Show quoteHide quote

news:IIsQlK1nGHA.4612@TK2MSFTNGXA01.phx.gbl...
> Hi Cj,
>
> It seems Cor Ligthert [MVP] provided an incorrect URL for queue class, I
> think he is referring the URL below:
> "Queue Class"
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/
> frlrfsystemcollectionsqueueclasstopic.asp
>
> There are several container classes in .Net may fit your need, such as
> ArrayList, Hashtable, Queue etc..., they all exist under
> System.Collections
> namespace. They all have different usages, you may refer to MSDN for their
> difference and choose the suitable for using as memory container table.
>
> Hope this helps!
>
> Best regards,
> Jeffrey Tan
> Microsoft Online Community Support
> ==================================================
> When responding to posts, please "Reply to Group" via your newsreader so
> that others may learn and benefit from your issue.
> ==================================================
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
>

5 Jul 2006 1:49 PM

cj

I'm don't think that's what I'm looking for. My program creates threads
to handle IP connections made to it. I've seen up to 66 concurrent
threads running to date. But usually it's around 3 or 4. For
accountability purposes each thread uses the MyStringLogger class I
posted in my first message to write it's results to a log file.
SyncLock is used to ensure only one thread is writing data at a time.

Now I'm trying to write into this program another type of log. Each
thread will be required to write two fields to an in memory db table.
Why--Each thread receives a request from a IP client then calculates and
sends a response to it. Part of the calculations involve other machines
and if the network is down the threads can't calculate the response so
they return an error code. In the future if the network is down I want
the program to search the new in memory db table for the last time that
question was asked by an ip client and return the same answer as it will
most likely still be correct.

Perhaps hourly a maintenance routine will be run to remove entries from
this in memory db table older than X hours or minutes or whatever is
determined to be appropriate.

Any suggestions?

Cor Ligthert [MVP] wrote:
Show quoteHide quote

> Jeffrey,
>
> Thank you, I did not copy it this was from a previous answer, mine was
>
> http://msdn2.microsoft.com/en-us/library/system.collections.queue.aspx
>
> A little bit shorter than your URL.
>
> By the way, the queue class (FIFO) is extremely sufficient with multi
> threading.
>
> Cor
>
> ""Jeffrey Tan[MSFT]"" <je***@online.microsoft.com> schreef in bericht
> news:IIsQlK1nGHA.4612@TK2MSFTNGXA01.phx.gbl...
>> Hi Cj,
>>
>> It seems Cor Ligthert [MVP] provided an incorrect URL for queue class, I
>> think he is referring the URL below:
>> "Queue Class"
>> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/
>> frlrfsystemcollectionsqueueclasstopic.asp
>>
>> There are several container classes in .Net may fit your need, such as
>> ArrayList, Hashtable, Queue etc..., they all exist under
>> System.Collections
>> namespace. They all have different usages, you may refer to MSDN for their
>> difference and choose the suitable for using as memory container table.
>>
>> Hope this helps!
>>
>> Best regards,
>> Jeffrey Tan
>> Microsoft Online Community Support
>> ==================================================
>> When responding to posts, please "Reply to Group" via your newsreader so
>> that others may learn and benefit from your issue.
>> ==================================================
>> This posting is provided "AS IS" with no warranties, and confers no
>> rights.
>>
>
>

5 Jul 2006 3:17 PM

Cor Ligthert [MVP]

cj,

Reading it, and trying to understand it, would I go to the sorted list (with
a good created key) or the hashtable with the same as already stated by
Jeffrey,

Cor

Show quoteHide quote

"cj" <cj@nospam.nospam> schreef in bericht
news:uQJyWnDoGHA.776@TK2MSFTNGP04.phx.gbl...
> I'm don't think that's what I'm looking for. My program creates threads
> to handle IP connections made to it. I've seen up to 66 concurrent
> threads running to date. But usually it's around 3 or 4. For
> accountability purposes each thread uses the MyStringLogger class I posted
> in my first message to write it's results to a log file. SyncLock is used
> to ensure only one thread is writing data at a time.
>
> Now I'm trying to write into this program another type of log. Each
> thread will be required to write two fields to an in memory db table.
> Why--Each thread receives a request from a IP client then calculates and
> sends a response to it. Part of the calculations involve other machines
> and if the network is down the threads can't calculate the response so
> they return an error code. In the future if the network is down I want
> the program to search the new in memory db table for the last time that
> question was asked by an ip client and return the same answer as it will
> most likely still be correct.
>
> Perhaps hourly a maintenance routine will be run to remove entries from
> this in memory db table older than X hours or minutes or whatever is
> determined to be appropriate.
>
> Any suggestions?
>
>
> Cor Ligthert [MVP] wrote:
>> Jeffrey,
>>
>> Thank you, I did not copy it this was from a previous answer, mine was
>>
>> http://msdn2.microsoft.com/en-us/library/system.collections.queue.aspx
>>
>> A little bit shorter than your URL.
>>
>> By the way, the queue class (FIFO) is extremely sufficient with multi
>> threading.
>>
>> Cor
>>
>> ""Jeffrey Tan[MSFT]"" <je***@online.microsoft.com> schreef in bericht
>> news:IIsQlK1nGHA.4612@TK2MSFTNGXA01.phx.gbl...
>>> Hi Cj,
>>>
>>> It seems Cor Ligthert [MVP] provided an incorrect URL for queue class, I
>>> think he is referring the URL below:
>>> "Queue Class"
>>> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/
>>> frlrfsystemcollectionsqueueclasstopic.asp
>>>
>>> There are several container classes in .Net may fit your need, such as
>>> ArrayList, Hashtable, Queue etc..., they all exist under
>>> System.Collections
>>> namespace. They all have different usages, you may refer to MSDN for
>>> their
>>> difference and choose the suitable for using as memory container table.
>>>
>>> Hope this helps!
>>>
>>> Best regards,
>>> Jeffrey Tan
>>> Microsoft Online Community Support
>>> ==================================================
>>> When responding to posts, please "Reply to Group" via your newsreader so
>>> that others may learn and benefit from your issue.
>>> ==================================================
>>> This posting is provided "AS IS" with no warranties, and confers no
>>> rights.
>>>
>>

6 Jul 2006 2:23 AM

Jeffrey Tan[MSFT]

Hi Cj,

Thanks for your feedback!

Based on my reading, your main concern is writing 2 fields to the memory
table instead of 1 field.

I think you have 2 choice to resolve this:
1. If one of your field is unique, you can use it as a key for lookup. Just
as Cor suggested, you may use SortedList or Hashtable for storage, since
they both use a key for lookup. So your first field is used as a key, and
the other field is stored in the SortedList/Hashtable associated with the
key(first field). This implementation is easy.
2. If your 2 fields are not unique, you can implement a customized class
which contains 2 properties to store these 2 fields, and you may store this
class instance in the System.Collections.* class. Choose what class in this
namespace you want.

Thanks.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
==================================================
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
==================================================
This posting is provided "AS IS" with no warranties, and confers no rights.