RDBMS and Group Cache

Question

We have noticed that when the group cache is reloaded, the
RDBMSDelegate.getGroup(String) method is called for each user that is
either logging into the system or doing some sort of role authentification
against the group cache.
This method in turn calls RDBMSDelegate.getGroupInternal(String, ResultSet),
which then parses the result set of the members of the group. So, if 5
members of the Employee group are logged into the server, the getGroup()
method is called 5 times concurrently. These concurrent method calls seem to
correspond with severe performance degradation since the method parses a
resultset of 3000 records each time its called.
We are using the example RDMBS security code and running WL6.0 sp1 on Win2K.
Is there any modified rdbms code out there that would improve the
performance of the group cache reload, or lock calls to the getGroups so
that the first call is the only one that parses the recordset and concurent
calls would be directed to the cache?
Thanks,
Pete

Answer 1

The philosophy behind the plan is when the group is first required you
just get any empty group object (sort of a wrapper class for a
Hashtable), then you call the database to find out if a user is in the
group only when you have to (this will lead to a lot more database
calls, but only retrieve the required lines, and them only one at a
time, as opposed to making one call which retrieves absolutely all of
the information.)
so RDBMSRealm.getGroup looks like this
public Group getGroup(String name){
RDBMSDelegate delegate = getDelegate();
try{
if (delegate.checkForGroup(name)){
return new RDBMSGroup(name,this,new Hashtable());
}else{
return null;
}catch (SQLException e){
delegate.close();
delegate = null;
throw new RDBMSException("caught SQL exception", e);
}finally{
returnDelegate(delegate);
Where RDMBSDelegate.checkForGroup just calls the database to see if
there is a group of the name given
And RDBMSGroup.isMember() looks like this
public boolean isMember(Principal member){
if (this.getName().equals("everyone")){
//everyone is in the 'everyone' group
return true;
}else{
try{
User user = (User)member;
//check if the member is in the Hashtable of known members
if (members.containsValue(user)){//user is a known member
return true;
}else{//check the database
if (realm.isMember(this,user)){//database says user is in this
group
//add member to known users list(use member's getName() rather
than User's to avoid deprecated API)
this.members.put(member.getName(),user);
return true;
}else{
return false;
}catch(ClassCastException e){//not castable to class User
return false;
Which is enough for the general operation of security.
If you wish to be able to view all members in the group you will need
something that resembles the original functionality
Hope this helps. terry
Hi,
What do you mean by "populate the group lazily with the
isMember() method" ? isMember()
takes a Principal as its argument - where do you get that Principal??
A code example would be highly appreciated!!!
regards,
Simen R.
THorner <[email protected]> wrote:
The RDBMSRealm provided (certainly with WLS5.1, but I think also 6.*)
really isn't meant to be used for production - it is just an example.
The matter of getGroup() is the major performance hit, and I advise you
to treat it differently - an architecture taht works for us is to make
getGroup just return the RDBMSGroup object, without calling the
database, and to populate the group lazily with the isMember() method.
so isMember looks like
if (hasAlreadyBeenCheckedForAndIsAMember){
return true;
}else if (wasntAlreadyCheckedForbutIsInTheDatabase){
addToListOfCheckedForMembers;
return true;
}else{
return false;
terry
-----Original Message-----
From: Jason Collins [mailto:[email protected]]
Posted At: Fri 17 August 2001 20:33
Posted To: weblogic.developer.interest.security
Conversation: RDBMS and Group Cache
Subject: Re: RDBMS and Group Cache
Was any solution to this found? We would like to avoid
writing the changes
to RDMSRealm, but the current performance is pretty bad.
Thanks,
j
"Pete Arvanitis" <[email protected]> wrote in message
news:[email protected]...
We have noticed that when the group cache is reloaded, the
RDBMSDelegate.getGroup(String) method is called for each user that is
either logging into the system or doing some sort of role authentification
against the group cache.
This method in turn calls RDBMSDelegate.getGroupInternal(String,ResultSet),
which then parses the result set of the members of the group. So, if 5
members of the Employee group are logged into the server, the getGroup()
method is called 5 times concurrently. These concurrent method calls seem
to
correspond with severe performance degradation since the method parses a
resultset of 3000 records each time its called.
We are using the example RDMBS security code and running WL6.0 sp1 on
Win2K.
Is there any modified rdbms code out there that would improve the
performance of the group cache reload, or lock calls to the getGroups so
that the first call is the only one that parses the recordset andconcurent
calls would be directed to the cache?
Thanks,
Pete