[ApacheDS] [JDBM] Index .db files grow from attribute replace

[Martin Alderson]

Hi all,

Firstly, apologies if this mail arrives in HTML format.  My company is in the 
middle of switching e-mail systems and may be converting all outgoing mail to 
HTML at the moment.

I have found that when just replacing an indexed attributes value the JDBM 
table seems to grow.  From doing this 300000 times I find that I have a 66 meg 
uid.db file which is growing at the rate of around 2.2 meg per 10000 
modifications and showing no signs of slowing down.

This is with a stock ApacheDS 1.5.4.  The following code should allow you to 
reproduce the problem:

////////////////////////////////////////////////////////////
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.directory.BasicAttribute;
import javax.naming.directory.DirContext;
import javax.naming.directory.ModificationItem;
import javax.naming.ldap.InitialLdapContext;
import javax.naming.ldap.LdapContext;

public class StressTestIndex {

    public static void main (String[] args) throws Exception {
        Hashtable env = new Hashtable();
        env.put(Context.SECURITY_PRINCIPAL, "uid=admin,ou=system");
        env.put(Context.SECURITY_CREDENTIALS, "secret");
        env.put(Context.SECURITY_AUTHENTICATION, "simple");
        env.put(Context.INITIAL_CONTEXT_FACTORY, 
"com.sun.jndi.ldap.LdapCtxFactory");
        env.put(Context.PROVIDER_URL, "ldap://localhost:10389/";);

        LdapContext ldapContext = (LdapContext) new InitialLdapContext(env, 
null);
        
        for (int i = 0; i < 100000; i++) {
            ldapContext.modifyAttributes("uid=admin,ou=system", new 
ModificationItem[] { new ModificationItem(DirContext.REPLACE_ATTRIBUTE, new 
BasicAttribute("uid", "admin")) });
        }
    }

}
////////////////////////////////////////////////////////////

Emmanuel pointed me to the nifty LaunchDiagnosticUI extended request which I 
send as:
  ldapContext.extendedOperation(new LaunchDiagnosticUiRequest(0));

Looking at the JDBM table with this tool it looks like the index only has the 
one entry in it as it should - so I think the rest of the space in the db file 
must be wasted space.  Does anyone know if the JDBM table can be compacted?  If 
it can should ApacheDS be doing that periodically?

Thanks,

Martin

<<attachment: winmail.dat>>