Y
yashgt
Hi,
We have a control Logo.ascx, which queries the DB to obtain the logo
image from a blob in the DB and renders it on the page.
The logo does not change frequently and hence we have tried to create
a cache for it:
<%@ OutputCache Duration="600" VaryByParam="None"
SqlDependency="EMAMDB:EMAM_Clients" %>
The cache will thus be invalidated every 10 min and also depending on
the changes to the EMAM_Clients table which has only one entry.
The dependency is set as follows:
<caching>
<sqlCacheDependency enabled="true" pollTime="1000">
<databases>
<add name="EMAMDB" connectionStringName="EMAMConnectionString"/>
</databases>
</sqlCacheDependency>
</caching>
The polling thus happens every second.
So we expect that if we refresh the page repeatedly once, the DB
stored proc that retrieves the logo should not be called each time.
However this is not the observed case. Almost every alternate refresh
causes the DB to be queried. We have also traced the code to verify
this. We have seen the
dbo.AspNet_SqlCachePollingStoredProcedure being called every second,
which means the Changes do get tracked, and we know for sure that
nobody is changing the table.
Why then is the cache invalidated every now and then?
Thanks,
Yash
We have a control Logo.ascx, which queries the DB to obtain the logo
image from a blob in the DB and renders it on the page.
The logo does not change frequently and hence we have tried to create
a cache for it:
<%@ OutputCache Duration="600" VaryByParam="None"
SqlDependency="EMAMDB:EMAM_Clients" %>
The cache will thus be invalidated every 10 min and also depending on
the changes to the EMAM_Clients table which has only one entry.
The dependency is set as follows:
<caching>
<sqlCacheDependency enabled="true" pollTime="1000">
<databases>
<add name="EMAMDB" connectionStringName="EMAMConnectionString"/>
</databases>
</sqlCacheDependency>
</caching>
The polling thus happens every second.
So we expect that if we refresh the page repeatedly once, the DB
stored proc that retrieves the logo should not be called each time.
However this is not the observed case. Almost every alternate refresh
causes the DB to be queried. We have also traced the code to verify
this. We have seen the
dbo.AspNet_SqlCachePollingStoredProcedure being called every second,
which means the Changes do get tracked, and we know for sure that
nobody is changing the table.
Why then is the cache invalidated every now and then?
Thanks,
Yash