Is possible to get negative count of cache entry

[dex80526]

Hi, all:

I am wondering if possible a cache returns a negative number for number of cache entries.

For example, in the following code, is possible the count negative?

int count = cache.size();

Can I assume the size() never return negative value in any configurations?

Other questions: how does infinispan keep the count of the size of a cache?  is there any performance penality if I call cache.size() operation periodically?

[matlach]

Hi dex,

Have a look at the SizeCommand implementation :

org.infinispan.commands.read

public class SizeCommand extends AbstractLocalCommand implements VisitableCommand {


   @Override
   public Integer perform(InvocationContext ctx) throws Throwable {
      if (noTxModifications(ctx)) {
         return container.size();
      }

      int size = container.size();
      for (CacheEntry e: ctx.getLookedUpEntries().values()) {
         if (e.isCreated()) {
            size ++;
         } else  if (e.isRemoved()) {
            size --;
         }
      }

      return Math.max(size, 0);
   }
}

It's definitely impossible to obtain a negative value.

For the performance impact, by reading the code I'm having trouble figuring it out since the size command is replicated across the cluster since it's flagged by both LocalCommand and VisitableCommand (thus ReplicableCommand).

Guess a small breakpoint here in debug and you'll find really soon

[dex80526]

thanks for the response. I'll do a debug session as you suggested.

[galder.zamarreno]

Thx Mathieu for helping out!