2 connections can be opened simultaneously during some DataCache work inside
single query.getResultList()
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Key: OPENJPA-2019
URL: https://issues.apache.org/jira/browse/OPENJPA-2019
Project: OpenJPA
Issue Type: Bug
Components: datacache, kernel, query
Affects Versions: 2.0.0
Environment: WinXP SP3, JDK 1.6.0_21, Postgres
Reporter: Oleg Lyalikov
Test configuration:
@Entity
public class Document { ... }
@Entity
public class Person {
...
@JoinTable(name="person_document", joinColumns =
{@JoinColumn(name="person_id", referencedColumnName="ID")}, inverseJoinColumns
= {@JoinColumn(name="documents_id", referencedColumnName="ID")})
@OneToMany(fetch = FetchType.EAGER)
private List<Document> documents;
...
}
Test case:
0. Set DataCache to: true(CacheSize=40, SoftReferenceSize=0), and limit
connection pool size by 1 connection
1. Create 20 objects of Person entity (+ 3 documents per each Person): 80
objects total (only half of objects can be located in data cache)
2. Clear entity manager and run query "SELECT p FROM Person p WHERE p.id IN
(?1, ?2, ... , ?20)"
Openjpa tries to open second connection at some time and fails.
Attached test project and stack trace of getting second connection.
The problem is significant for me because I have lots of threads executing
queries like in 2. point and I have hard limits on connection pool size. I
cannot have connection_pool_size > possible_threads_count. So at some time I
get connection pool exhausted and application stops working.
It seems that the problem is related to DataCache work and L1 cache work (I
didn't reproduce the problem with big sized or small sized DataCache - to
reproduce it's better to assign DataCache size = 1/2 of total query objects
count. Also I didn't reproduce it with Ehcache and openjpa-2.2.0 with Lru=true).
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