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http://jira.jboss.com/jira/browse/EJBTHREE-649?page=comments#action_12340482 ]
J-C jc commented on EJBTHREE-649:
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It looks like we have the same problem (maybe a duplicate with
http://jira.jboss.com/jira/browse/EJBTHREE-326).
I tried to debug that. From what I understand problem was due to the flush algorithm.
(with FlushMode to Auto, a flush is performed before each query). When there is a lot of
objects resolved in a transaction, flush algorithm slow down. I've tried to instrument
classes but it just improves a little perf
(
http://opensource.atlassian.com/projects/hibernate/browse/HHH-1207).
A solution to improve performance is to be very careful with CascadeType.PERSIST (limit as
much as possible). With this mode, flush has more jobs to do.
Query Performance within transaction decreasing progressively when
using default FlushModeType.AUTO
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Key: EJBTHREE-649
URL:
http://jira.jboss.com/jira/browse/EJBTHREE-649
Project: EJB 3.0
Issue Type: Bug
Affects Versions: EJB 3.0 RC8 - FD
Environment: WinXP SP2, Oracle 9i Enterprise Rel. 9.2.0.1.0, JBoss 4.0.4GA,
EJB3.0 RC8-FD
Reporter: Andreas Zimmer
Query Performance within a Transaction is progressively decreasing when working with
EJB3.0 default FlushModeType.AUTO:
20 queries/reads within transaction - 10 msecs average per query/read
1000 (same as before) queries/reads within transaction - 130 msecs average per query/read
(factor 13+)
With FlushModeType.COMMIT query performance within the same scenario ist constant at
expected 10 msecs but FlushModeType.COMMIT imposes restrictions which our projects
can't cope with. We need updates within transaction being visible in subsequent
queries of the same transaction.
The case is explained in some detail in the JBoss Forum Thread as provided in JBoss Forum
Reference.
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