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Posted to user-cs@ibatis.apache.org by Sara O'Neal <sa...@cadre5.com> on 2007/02/15 01:50:42 UTC

Question about Caching in iBatis .NET

I am new to iBatis, and have been playing around with the caching
feature.  I'm not sure if I am doing something wrong, or if it is
working incorrectly.  I am trying to use the FIFO caching model in
iBatis .NET, DataMapper 1.5.1, using SQL Server 2005.  Here is my model:
 
<cacheModels>
    <cacheModel id="addressCacheF" implementation="FIFO">
        <flushInterval hours="24" />
        <flushOnExecute statement="InsertAddress" />
        <flushOnExecute statement="UpdateAddress" />
        <property name="CacheSize" value="5" />
    </cachModel>
</cacheModels>
 
I also have caching enabled:
 
<settings>
         <setting useStatementNamespaces="true" />
         <setting cacheModelsEnabled="true" />
         <setting validateSqlMap="true" />
</settings>
 
Please excuse any errors, because I retyped this.  So, from what I
understand, this is using a First in First Out algorithm for caching and
it caches a Maximum of 5 items.  However, when I apply this cache model
to the code that I wrote, it doesn't seem to work correctly.  I am using
SQL Server Profiler to trace any database events (I also enabled logging
for iBatis to track cache hits/misses).  The data I am retrieving is
from a table of clients, and I am retrieving the client by a client id.
The sequence I am using is:
 
1, 2, 3, 4, 5
 
For this sequence there are 5 cache misses and all 5 should now be in
the cache.  Next, I use the same sequence and get 5 cache hits.  Both
the log and the profiler back this up.
 
Then, I enter 6 and get a cache miss.  This means 2 things.  First, 6 is
going to be added to the cache.  Second, since the cache is full, it
uses FIFO to replace the first item in the cache, which was 1.  So, I
can now enter this sequence:
 
2, 3, 4, 5, 6
 
Sure enough, I get 5 cache hits.  Next, I want to go back to 1.  When I
enter that value, I should get a miss, and indeed do.  It should also
add the object to the cache, mean I should have:  3, 4, 5, 6, 1 in my
cache.  BUT, it doesn't, I still have 2, 3, 4, 5, 6 in my cache.  More
than that, though, when I try 7, it gets added to the cache, but none of
the other objects get replaced!  I can add 8, 9, 10, 11...getting misses
on each the first time.  However, I can then go back and try 2, 3, 4, 5,
6, 7, 8, 9, 10, 11 and get hits on every single one of them.  Finally, I
try 1 again and get a miss...I continue trying and continue getting a
miss.
 
So, is there something I missing about the caching, or is there
something I not understanding about the cache size, or what?
 
I have tried using the other cache implementations as well.  I'm not
sure what the MEMORY is supposed to do...so I can't really tell if it is
working correctly or not.  The LRU, however, doesn't seem to work
correctly either, but that is a completely different story.  Please
advise if I should report this as a bug, or if I do not understand the
way it SHOULD work.
 
thanks,
Sara O'Neal
Software Developer, Cadre5, LLC
sara.oneal@cadre5.com <ma...@cadre5.com>

RE: Question about Caching in iBatis .NET

Posted by Sara O'Neal <sa...@cadre5.com>.
So no one can help me with this problem or tell me if it is a bug?
 
thanks,
Sara

________________________________

From: Sara O'Neal 
Sent: Wednesday, February 14, 2007 7:51 PM
To: user-cs@ibatis.apache.org
Subject: Question about Caching in iBatis .NET


I am new to iBatis, and have been playing around with the caching
feature.  I'm not sure if I am doing something wrong, or if it is
working incorrectly.  I am trying to use the FIFO caching model in
iBatis .NET, DataMapper 1.5.1, using SQL Server 2005.  Here is my model:
 
<cacheModels>
    <cacheModel id="addressCacheF" implementation="FIFO">
        <flushInterval hours="24" />
        <flushOnExecute statement="InsertAddress" />
        <flushOnExecute statement="UpdateAddress" />
        <property name="CacheSize" value="5" />
    </cachModel>
</cacheModels>
 
I also have caching enabled:
 
<settings>
         <setting useStatementNamespaces="true" />
         <setting cacheModelsEnabled="true" />
         <setting validateSqlMap="true" />
</settings>
 
Please excuse any errors, because I retyped this.  So, from what I
understand, this is using a First in First Out algorithm for caching and
it caches a Maximum of 5 items.  However, when I apply this cache model
to the code that I wrote, it doesn't seem to work correctly.  I am using
SQL Server Profiler to trace any database events (I also enabled logging
for iBatis to track cache hits/misses).  The data I am retrieving is
from a table of clients, and I am retrieving the client by a client id.
The sequence I am using is:
 
1, 2, 3, 4, 5
 
For this sequence there are 5 cache misses and all 5 should now be in
the cache.  Next, I use the same sequence and get 5 cache hits.  Both
the log and the profiler back this up.
 
Then, I enter 6 and get a cache miss.  This means 2 things.  First, 6 is
going to be added to the cache.  Second, since the cache is full, it
uses FIFO to replace the first item in the cache, which was 1.  So, I
can now enter this sequence:
 
2, 3, 4, 5, 6
 
Sure enough, I get 5 cache hits.  Next, I want to go back to 1.  When I
enter that value, I should get a miss, and indeed do.  It should also
add the object to the cache, mean I should have:  3, 4, 5, 6, 1 in my
cache.  BUT, it doesn't, I still have 2, 3, 4, 5, 6 in my cache.  More
than that, though, when I try 7, it gets added to the cache, but none of
the other objects get replaced!  I can add 8, 9, 10, 11...getting misses
on each the first time.  However, I can then go back and try 2, 3, 4, 5,
6, 7, 8, 9, 10, 11 and get hits on every single one of them.  Finally, I
try 1 again and get a miss...I continue trying and continue getting a
miss.
 
So, is there something I missing about the caching, or is there
something I not understanding about the cache size, or what?
 
I have tried using the other cache implementations as well.  I'm not
sure what the MEMORY is supposed to do...so I can't really tell if it is
working correctly or not.  The LRU, however, doesn't seem to work
correctly either, but that is a completely different story.  Please
advise if I should report this as a bug, or if I do not understand the
way it SHOULD work.
 
thanks,
Sara O'Neal
Software Developer, Cadre5, LLC
sara.oneal@cadre5.com <ma...@cadre5.com>