persistent cache in SQL Server

[Trapulo]

Hello,
I'm developing an asp.net application that is connected to a remote system
using WCF (wshttp binding). So I want to use a local cache to manage data
that I receive from remote service.

I'm using caching block from MS application enterprise library 4.1,
configured to use a SQL Server cache. That's great: it works with very
little effort.
However I noticed that caching block mantains a copy of the cache in memory
(loading all cache when it starts). I want to matain data only in SQL
Server, because are very large data that I mantain in cache for a lot of
time (about 7 days). Is there any way I can use ONLY the SQL Server
repository instead of in.memory AND Sql Server?

thanks

[Gregory A. Beamer]

Re: persistent cache in SQL Server

The idea behind cache, as MS has it, is to save time getting information by
putting it in memory. SQL is there as a backup, but it is not designed to be
a primary mechanism, as SQL retrievals are slower than memory. If you want
to store long term temporary infomration in SQL and not really cache,
consider rolling your own mechanism rather than use the MS cache bits, as
you are not really caching here.

--
Gregory A. Beamer
MVP: MCP: +I, SE, SD, DBA

Blog:

http://feeds.feedburner.com/GregoryBeamer

*************** *************** **************
| Think Outside the Box! |
*************** *************** **************
"Trapulo" <trapulo2@noema il.noemailwrote in message
news:DFC6D3B3-0E83-45BA-B002-AD4DA5D0F101@mi crosoft.com...

Hello,
I'm developing an asp.net application that is connected to a remote system
using WCF (wshttp binding). So I want to use a local cache to manage data
that I receive from remote service.
>
I'm using caching block from MS application enterprise library 4.1,
configured to use a SQL Server cache. That's great: it works with very
little effort.
However I noticed that caching block mantains a copy of the cache in
memory (loading all cache when it starts). I want to matain data only in
SQL Server, because are very large data that I mantain in cache for a lot
of time (about 7 days). Is there any way I can use ONLY the SQL Server
repository instead of in.memory AND Sql Server?
>
thanks
>
>
>
>

[Trapulo]

Re: persistent cache in SQL Server

Yes: I need a cache that saves time getting data from remote WCF Server,
instead of saving data from getting data from SQL Server. So SQL is a lot
faster that a remote WCF call and I need a "real cache"...

Is there some ready library I can use someone can suggest? I not want to
write my own code to have a very common scenario...

thanks



"Gregory A. Beamer" <NoSpamMgbworld @comcast.netNoS pamMwrote in message
news:uP19wqyRJH A.5860@TK2MSFTN GP02.phx.gbl...

The idea behind cache, as MS has it, is to save time getting information
by putting it in memory. SQL is there as a backup, but it is not designed
to be a primary mechanism, as SQL retrievals are slower than memory. If
you want to store long term temporary infomration in SQL and not really
cache, consider rolling your own mechanism rather than use the MS cache
bits, as you are not really caching here.
>
--
Gregory A. Beamer
MVP: MCP: +I, SE, SD, DBA
>
Blog:

http://feeds.feedburner.com/GregoryBeamer

>
*************** *************** **************
| Think Outside the Box! |
*************** *************** **************
"Trapulo" <trapulo2@noema il.noemailwrote in message
news:DFC6D3B3-0E83-45BA-B002-AD4DA5D0F101@mi crosoft.com...

>Hello,
>I'm developing an asp.net application that is connected to a remote
>system using WCF (wshttp binding). So I want to use a local cache to
>manage data that I receive from remote service.
>>
>I'm using caching block from MS application enterprise library 4.1,
>configured to use a SQL Server cache. That's great: it works with very
>little effort.
>However I noticed that caching block mantains a copy of the cache in
>memory (loading all cache when it starts). I want to matain data only in
>SQL Server, because are very large data that I mantain in cache for a lot
>of time (about 7 days). Is there any way I can use ONLY the SQL Server
>repository instead of in.memory AND Sql Server?
>>
>thanks
>>
>>
>>
>>

>

[Allen Chen [MSFT]]

Re: persistent cache in SQL Server

Hi Trapulo,

From your description you want to store the data into SQL Server that is
retrieved from WCF, right? If so, as Gregory said, it's not a cache.

First I need to confirm if you need a global data structure or a
user-independent data structure. If the data is user independent I suggest
you use the ASP.NET Session. As we know, session can be stored in SQL
Server:

http://support.microsoft.com/kb/317604

You can call WCF method and store the retrieved data into Session.
If it's global data you can design a table:

Key P.K.
Value
TimeStamp

Then store the retrieved data into database and use Sql Server Agent
Service to remove the expired records every 7 days.

Please let me know if you have any questions.

Regards,
Allen Chen
Microsoft Online Support

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[Trapulo]

Re: persistent cache in SQL Server

"Allen Chen [MSFT]" <v-alchen@online.m icrosoft.comwro te in message
news:qxsUqXSSJH A.4804@TK2MSFTN GHUB02.phx.gbl. ..

Hi Trapulo,
>
From your description you want to store the data into SQL Server that is
retrieved from WCF, right? If so, as Gregory said, it's not a cache.

Yes
However I think it's sure a cache

http://en.wikipedia.org/wiki/Cache:

"In computer science, a cache (pronounced /kæʃ/) is a collection of data
duplicating original values stored elsewhere or computed earlier, where the
original data is expensive to fetch (owing to longer access time) or to
compute, compared to the cost of reading the cache"

First I need to confirm if you need a global data structure or a
user-independent data structure

global data.

If the data is user independent I suggest
you use the ASP.NET Session. As we know, session can be stored in SQL
Server:
>

http://support.microsoft.com/kb/317604

>
>You can call WCF method and store the retrieved data into Session.

this can be interesting. However, as I said, data are global

If it's global data you can design a table:
>
Key P.K.
Value
TimeStamp
>
Then store the retrieved data into database and use Sql Server Agent
Service to remove the expired records every 7 days.
>
Please let me know if you have any questions.

Ok thanks.
I was hoping to find a full featured complete library (as logging block).
In fact, however, it can be good to have a copy either in memory and sql
server. But logging block retains in memory all data. If it can retain, for
example, last 100 objects in memory, and 10000 in sql, it will be great (100
is too little to my requirenments, an 10000 is to big to leave in memory).
Instead of this, it has just a single parameter that sets memory and sql
cache. Is there any easy way we can extend logging block to have this goal?

thanks

[Allen Chen [MSFT]]

Re: persistent cache in SQL Server

Hi Trapulo,

Quote from Trapulo =============== =============== =============== ====
In fact, however, it can be good to have a copy either in memory and sql
server. But logging block retains in memory all data. If it can retain, for
example, last 100 objects in memory, and 10000 in sql, it will be great
(100
is too little to my requirenments, an 10000 is to big to leave in memory).
Instead of this, it has just a single parameter that sets memory and sql
cache.
=============== =============== =============== ====

As far as I know currently the enterprise library does not provide that
flexibility. The SQL data storage for the caching block is mainly used to
backup cached data in case in-memory cache is lost due to application
crash. It's not proposed as a primary cache.

To achieve your requirement we can write our own cache mechanism. The
pseudocode may be:

using System.Web.Cach ing;

public class MyCacheManager
{
private static Cache _cache = new Cache();
public static void AddCache(object data,object key)
{

if (_cache.Count 100)
{
//insert data to database
}
else
{
//add data to _cache
//optional, add a copy to database in case in-memory cache
is lost.
}


}
public static object GetCache(object key)
{
//if the data retrieved from _cache is null, access database
//if still no record retrieved, return null.
}

}

We can design a table to store the data and use SQL Server agent to remove
records every 7 days.

You can also consider using distributed caching. Though it's not the means
as you thought above it's another option that can increase performance.

http://www.codeplex.com/SharedCache

If you have further questions please feel free to ask.

Regards,
Allen Chen
Microsoft Online Community Support