[jira] [Commented] (POOL-396) Exceptions in validation can cause an object's lifecycle to be stuck in EVICTION state
[
https://issues.apache.org/jira/browse/POOL-396?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17366675#comment-17366675
]
Jeremy Kong commented on POOL-396:
--
No worries! That's good to hear. Yep, rethrowing seems reasonable - I've added
that.
> Exceptions in validation can cause an object's lifecycle to be stuck in
> EVICTION state
> --
>
> Key: POOL-396
> URL: https://issues.apache.org/jira/browse/POOL-396
> Project: Commons Pool
> Issue Type: Bug
>Affects Versions: 2.4.2, 2.9.0
>Reporter: Jeremy Kong
>Priority: Major
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> Currently, if validation of an object throws an exception when testing an
> idle object during eviction, an exception will be thrown from the evict()
> method. This causes the object to be left in the EVICTION state, but still be
> present in the idleObjects queue.
> Future runs of the eviction thread will run into an infinite loop, because
> they pick up the afflicted object from the queue, fail to set its state to
> EVICTION, don't count it as a test, and repeat ad infinitum. This infinite
> loop means that no further evictions will take place; it also causes
> increases in garbage collection owing to allocation of the EvictionIterator
> on each loop iteration.
> This test added to TestGenericObjectPool (plus a small change allowing
> exceptions to be thrown from the validateObject method of SimpleFactory)
> reproduces the issue.
> {code:java}
> @Test
> @Timeout(value = 6, unit = TimeUnit.MILLISECONDS)
> public void testExceptionInValidationDuringEviction() throws Exception {
> genericObjectPool.setMaxIdle(1);
> genericObjectPool.setMaxTotal(2);
> genericObjectPool.setNumTestsPerEvictionRun(1);
> genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(0));
> genericObjectPool.setTestWhileIdle(true);
> String active = genericObjectPool.borrowObject();
> genericObjectPool.returnObject(active);
> simpleFactory.setThrowExceptionOnValidate(true);
> try {
> genericObjectPool.evict();
> } catch (Exception e) {
> // OK that a given run fails. But the object should still be evicted.
> }
> genericObjectPool.evict(); // currently fails: causes an infinite loop!
> assertEquals(0, genericObjectPool.getNumActive());
> assertEquals(0, genericObjectPool.getNumIdle());
> }
> {code}
> It seems that protection against exceptions thrown by validation code exist
> elsewhere (e.g. in borrowObject()); similarly, protections against exceptions
> thrown by user eviction policy code exist in evict(). So it looks like the
> testWhileIdle() portion of evict() needs to similarly be protected.
> Thanks!
> Jeremy
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[jira] [Commented] (POOL-396) Exceptions in validation can cause an object's lifecycle to be stuck in EVICTION state
[
https://issues.apache.org/jira/browse/POOL-396?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17364427#comment-17364427
]
Jeremy Kong commented on POOL-396:
--
I see, that makes sense. Yep, I've updated the PR to do that, and added the
analogous patch for GenericKeyedObjectPool (plus tests).
Would NoSuchElementException be the right exception to throw in this case? I've
copied it from the existing validation failure handling code, though while that
makes sense for e.g. borrowObject() I don't know if it does for evict().
> Exceptions in validation can cause an object's lifecycle to be stuck in
> EVICTION state
> --
>
> Key: POOL-396
> URL: https://issues.apache.org/jira/browse/POOL-396
> Project: Commons Pool
> Issue Type: Bug
>Affects Versions: 2.4.2, 2.9.0
>Reporter: Jeremy Kong
>Priority: Major
> Time Spent: 20m
> Remaining Estimate: 0h
>
> Currently, if validation of an object throws an exception when testing an
> idle object during eviction, an exception will be thrown from the evict()
> method. This causes the object to be left in the EVICTION state, but still be
> present in the idleObjects queue.
> Future runs of the eviction thread will run into an infinite loop, because
> they pick up the afflicted object from the queue, fail to set its state to
> EVICTION, don't count it as a test, and repeat ad infinitum. This infinite
> loop means that no further evictions will take place; it also causes
> increases in garbage collection owing to allocation of the EvictionIterator
> on each loop iteration.
> This test added to TestGenericObjectPool (plus a small change allowing
> exceptions to be thrown from the validateObject method of SimpleFactory)
> reproduces the issue.
> {code:java}
> @Test
> @Timeout(value = 6, unit = TimeUnit.MILLISECONDS)
> public void testExceptionInValidationDuringEviction() throws Exception {
> genericObjectPool.setMaxIdle(1);
> genericObjectPool.setMaxTotal(2);
> genericObjectPool.setNumTestsPerEvictionRun(1);
> genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(0));
> genericObjectPool.setTestWhileIdle(true);
> String active = genericObjectPool.borrowObject();
> genericObjectPool.returnObject(active);
> simpleFactory.setThrowExceptionOnValidate(true);
> try {
> genericObjectPool.evict();
> } catch (Exception e) {
> // OK that a given run fails. But the object should still be evicted.
> }
> genericObjectPool.evict(); // currently fails: causes an infinite loop!
> assertEquals(0, genericObjectPool.getNumActive());
> assertEquals(0, genericObjectPool.getNumIdle());
> }
> {code}
> It seems that protection against exceptions thrown by validation code exist
> elsewhere (e.g. in borrowObject()); similarly, protections against exceptions
> thrown by user eviction policy code exist in evict(). So it looks like the
> testWhileIdle() portion of evict() needs to similarly be protected.
> Thanks!
> Jeremy
--
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[jira] [Commented] (POOL-396) Exceptions in validation can cause an object's lifecycle to be stuck in EVICTION state
[
https://issues.apache.org/jira/browse/POOL-396?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17362952#comment-17362952
]
Jeremy Kong commented on POOL-396:
--
I have proposed a fix in
[https://github.com/apache/commons-pool/pull/85|https://github.com/apache/commons-pool/pull/85].
> Exceptions in validation can cause an object's lifecycle to be stuck in
> EVICTION state
> --
>
> Key: POOL-396
> URL: https://issues.apache.org/jira/browse/POOL-396
> Project: Commons Pool
> Issue Type: Bug
>Affects Versions: 2.4.2, 2.9.0
>Reporter: Jeremy Kong
>Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Currently, if validation of an object throws an exception when testing an
> idle object during eviction, an exception will be thrown from the evict()
> method. This causes the object to be left in the EVICTION state, but still be
> present in the idleObjects queue.
> Future runs of the eviction thread will run into an infinite loop, because
> they pick up the afflicted object from the queue, fail to set its state to
> EVICTION, don't count it as a test, and repeat ad infinitum. This infinite
> loop means that no further evictions will take place; it also causes
> increases in garbage collection owing to allocation of the EvictionIterator
> on each loop iteration.
> This test added to TestGenericObjectPool (plus a small change allowing
> exceptions to be thrown from the validateObject method of SimpleFactory)
> reproduces the issue.
> {code:java}
> @Test
> @Timeout(value = 6, unit = TimeUnit.MILLISECONDS)
> public void testExceptionInValidationDuringEviction() throws Exception {
> genericObjectPool.setMaxIdle(1);
> genericObjectPool.setMaxTotal(2);
> genericObjectPool.setNumTestsPerEvictionRun(1);
> genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(0));
> genericObjectPool.setTestWhileIdle(true);
> String active = genericObjectPool.borrowObject();
> genericObjectPool.returnObject(active);
> simpleFactory.setThrowExceptionOnValidate(true);
> try {
> genericObjectPool.evict();
> } catch (Exception e) {
> // OK that a given run fails. But the object should still be evicted.
> }
> genericObjectPool.evict(); // currently fails: causes an infinite loop!
> assertEquals(0, genericObjectPool.getNumActive());
> assertEquals(0, genericObjectPool.getNumIdle());
> }
> {code}
> It seems that protection against exceptions thrown by validation code exist
> elsewhere (e.g. in borrowObject()); similarly, protections against exceptions
> thrown by user eviction policy code exist in evict(). So it looks like the
> testWhileIdle() portion of evict() needs to similarly be protected.
> Thanks!
> Jeremy
--
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[jira] [Created] (POOL-396) Exceptions in validation can cause an object's lifecycle to be stuck in EVICTION state
Jeremy Kong created POOL-396:
Summary: Exceptions in validation can cause an object's lifecycle
to be stuck in EVICTION state
Key: POOL-396
URL: https://issues.apache.org/jira/browse/POOL-396
Project: Commons Pool
Issue Type: Bug
Affects Versions: 2.9.0, 2.4.2
Reporter: Jeremy Kong
Currently, if validation of an object throws an exception when testing an idle
object during eviction, an exception will be thrown from the evict() method.
This causes the object to be left in the EVICTION state, but still be present
in the idleObjects queue.
Future runs of the eviction thread will run into an infinite loop, because they
pick up the afflicted object from the queue, fail to set its state to EVICTION,
don't count it as a test, and repeat ad infinitum. This infinite loop means
that no further evictions will take place; it also causes increases in garbage
collection owing to allocation of the EvictionIterator on each loop iteration.
This test added to TestGenericObjectPool (plus a small change allowing
exceptions to be thrown from the validateObject method of SimpleFactory)
reproduces the issue.
{code:java}
@Test
@Timeout(value = 6, unit = TimeUnit.MILLISECONDS)
public void testExceptionInValidationDuringEviction() throws Exception {
genericObjectPool.setMaxIdle(1);
genericObjectPool.setMaxTotal(2);
genericObjectPool.setNumTestsPerEvictionRun(1);
genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(0));
genericObjectPool.setTestWhileIdle(true);
String active = genericObjectPool.borrowObject();
genericObjectPool.returnObject(active);
simpleFactory.setThrowExceptionOnValidate(true);
try {
genericObjectPool.evict();
} catch (Exception e) {
// OK that a given run fails. But the object should still be evicted.
}
genericObjectPool.evict(); // currently fails: causes an infinite loop!
assertEquals(0, genericObjectPool.getNumActive());
assertEquals(0, genericObjectPool.getNumIdle());
}
{code}
It seems that protection against exceptions thrown by validation code exist
elsewhere (e.g. in borrowObject()); similarly, protections against exceptions
thrown by user eviction policy code exist in evict(). So it looks like the
testWhileIdle() portion of evict() needs to similarly be protected.
Thanks!
Jeremy
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