Win a copy of Think Java: How to Think Like a Computer Scientist this week in the Java in General forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

JBoss CMP read ahead cache problem

 
mri wu
Greenhorn
Posts: 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have a application which was deployed on OC4J application server and now need to be migrated to JBoss. After I change all the CMP ejb beans and successfully depoyed to JBoss 3.2.3 I found that the speed is extremly slow. By using profiling tool I found it was a JBoss CMP beans cause the peformance issue. Every time a JSp call CMP bean's get method will cause a database SQL call (n+1 issue). the simple snippet is like:

Object objRef = initialContext.lookup("ejb/LocalSessionActivitiesEJB");
SessionActivitiesHome home = (SessionActivitiesHome) objRef;
Collection collection = home.findAll();
for (Iterator iterator = collection.iterator(); iterator.hasNext() {
SessionActivities sa= (SessionActivities) iterator.next();
String id = sa.getName();
}
The detailed log related to cache act(enable TRACE):
==================================
JSP call to CMP:
Executing SQL: SELECT t0_s.ID FROM SESSION_ACTIVITIES t0_s
Add finder results: entity=SessionActivities results=[[.101.], [.102.], [.647.]] readahead=[JDBCReadAheadMetaData : strategy=on-load, pageSize=240, eagerLoadGroup=*]
RESET PERSISTENCE CONTEXT: id=[.101.]
load data: entity=SessionActivities pk=[.101.]
No preload data found: entity=SessionActivities pk=[.101.]
Default eager-load for entity: readahead=null
Executing SQL: SELECT MANDATORY_IND, COMPLETED_IND, ACT_COMMENTS, PLANNED_START_DATE, PLANNED_END_DATE, ACTUAL_START_DATE, ACTUAL_END_DATE, SESSACT_SEQ, SESSACT_TYPE, ROLE_ROLE, SESSACTTYP_ID, SESS_ID, AGEN_UID, TASK_1_ID, SESSUSR_USERID, SWIN_ID, EXTWIN_ID FROM SESSION_ACTIVITIES WHERE (ID=?)
Set parameter: index=1, jdbcType=INTEGER, value=101
RESET PERSISTENCE CONTEXT: id=[.102.]
load data: entity=SessionActivities pk=[.102.]
No preload data found: entity=SessionActivities pk=[.102.]
Default eager-load for entity: readahead=null
Executing SQL: SELECT MANDATORY_IND, COMPLETED_IND, ACT_COMMENTS, PLANNED_START_DATE, PLANNED_END_DATE, ACTUAL_START_DATE, ACTUAL_END_DATE, SESSACT_SEQ, SESSACT_TYPE, ROLE_ROLE, SESSACTTYP_ID, SESS_ID, AGEN_UID, TASK_1_ID, SESSUSR_USERID, SWIN_ID, EXTWIN_ID FROM SESSION_ACTIVITIES WHERE (ID=?)
Set parameter: index=1, jdbcType=INTEGER, value=102
Store command NOT executed. Entity is not dirty: pk=[.102.]
...
======================
Session bean call to CMP
Executing SQL: SELECT t0_s.ID FROM SESSION_ACTIVITIES t0_s
Add finder results: entity=SessionActivities results=[[.101.], [.102.], [.647.]] readahead=[JDBCReadAheadMetaData : strategy=on-load, pageSize=240, eagerLoadGroup=*]
RESET PERSISTENCE CONTEXT: id=[.101.]
load data: entity=SessionActivities pk=[.101.]
No preload data found: entity=SessionActivities pk=[.101.]
Eager-load for entity: readahead=[JDBCReadAheadMetaData : strategy=on-load, pageSize=240, eagerLoadGroup=*]
Executing SQL: SELECT ID, MANDATORY_IND, COMPLETED_IND, ACT_COMMENTS, PLANNED_START_DATE, PLANNED_END_DATE, ACTUAL_START_DATE, ACTUAL_END_DATE, SESSACT_SEQ, SESSACT_TYPE, ROLE_ROLE, SESSACTTYP_ID, SESS_ID, AGEN_UID, TASK_1_ID, SESSUSR_USERID, SWIN_ID, EXTWIN_ID FROM SESSION_ACTIVITIES WHERE (ID=?) OR (ID=?) OR (ID=?)
Set parameter: index=1, jdbcType=INTEGER, value=101
Set parameter: index=2, jdbcType=INTEGER, value=102
...(other Set parameter )
Add preload data: entity=SessionActivities pk=[.101.] field=mandatory_ind
Add preload data: entity=SessionActivities pk=[.101.] field=completed_ind
...(other Add preload )
RESET PERSISTENCE CONTEXT: id=[.102.]
load data: entity=SessionActivities pk=[.101.]
Preloading data: entity=SessionActivities pk=[.101.] cmpField=agen_uid
Preloading data: entity=SessionActivities pk=[.101.] cmpField=sess_id
... (other Preloading)
...
==================================
OC4J doean't have this issue before and will cache the database data even call a CMP from JSP but it seems JBoss will ONLY cache (using on-find or on-load strateg) database data when you call a CMP withing the same EJB container which mean you have to call a CMP from a session bean. I noticed here that JSP page can get Local EJB home and interface and EJB contaoner should smart enough to enable cache. Who can confirm that this is a not bug and I need some extra configuratrion? I hope I don't have to rewrite the old code to change all calls from JSP/ CMP to JSP/Session bean /CMP and this will be a nightmare to me(huge change). All I want is the running version and reasonable peformance. Is any way I can avoid to change the whole jsp file and enjoy the JBoss CMp cache benefit? Thanks in advance.
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic