Hello,

maybe deactivating trackback can help:
https://confluence.atlassian.com/doc/trackback-and-external-referrers-147487.html

Regards

I guess our only hope is to use twitter to complain about these bugs. I guess that's the reason why the twitter plugin was disabled at some point, probably a request from marketing.

Its happening with version 5.8.10

2015-09-14 13:52:04,067 WARN [scheduler_Worker-7] [com.atlassian.trackback.DefaultTrackbackFinder] findPingUrls Unable to connect to 'http://xxxxxxx.com': java.net.ConnectException: Connection refused: connect
java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:286)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:80)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:122)
at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:707)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:387)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at com.atlassian.trackback.TrackbackUtils.getUrlContent(TrackbackUtils.java:149)
at com.atlassian.trackback.DefaultTrackbackFinder.findPingUrls(DefaultTrackbackFinder.java:52)
at com.atlassian.confluence.util.task.TrackbackQueueItem.execute(TrackbackQueueItem.java:42)
at com.atlassian.core.task.AbstractTaskQueue.flush(AbstractTaskQueue.java:38)
at com.atlassian.quartz.jobs.TaskQueueFlushJob.doExecute(TaskQueueFlushJob.java:34)
at com.atlassian.quartz.jobs.AbstractJob.lambda$executeInternal$38(AbstractJob.java:129)
at com.atlassian.quartz.jobs.AbstractJob$$Lambda$96/1886192795.doInHibernate(Unknown Source)
at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:370)
at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:337)
at com.atlassian.quartz.jobs.AbstractJob.executeInternal(AbstractJob.java:125)
at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
at com.atlassian.scheduler.quartz1.Quartz1JobFactory$ClassLoaderProtectingWrappedJob.execute(Quartz1JobFactory.java:62)
at org.quartz.core.JobRunShell.run(JobRunShell.java:223)
at com.atlassian.confluence.schedule.quartz.ConfluenceQuartzThreadPool.lambda$runInThread$46(ConfluenceQuartzThreadPool.java:19)
at com.atlassian.confluence.schedule.quartz.ConfluenceQuartzThreadPool$$Lambda$93/1337602256.run(Unknown Source)

Same here with 5.7.3, application links do not work at all.

same with 5.7.1. Log file is full of these errors.

Running Confluence 5.4.2, this is still an issue:

2014-11-07 10:53:09,093 WARN [scheduler_Worker-1] [com.atlassian.trackback.DefaultTrackbackFinder] findPingUrls Error getting content of URL 'http://10.10.234.10/example.html': java.net.NoRouteToHostException: No route to host
java.net.NoRouteToHostException: No route to host
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
        at java.net.Socket.connect(Socket.java:579)
        at java.net.Socket.connect(Socket.java:528)
        at java.net.Socket.<init>(Socket.java:425)
        at java.net.Socket.<init>(Socket.java:280)
        at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:80)
        at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:122)
        at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:707)
        at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:387)
        at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
        at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
        at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
        at com.atlassian.trackback.TrackbackUtils.getUrlContent(TrackbackUtils.java:149)
        at com.atlassian.trackback.DefaultTrackbackFinder.findPingUrls(DefaultTrackbackFinder.java:52)
        at com.atlassian.confluence.util.task.TrackbackQueueItem.execute(TrackbackQueueItem.java:40)
        at com.atlassian.core.task.AbstractTaskQueue.flush(AbstractTaskQueue.java:38)
        at com.atlassian.quartz.jobs.TaskQueueFlushJob.doExecute(TaskQueueFlushJob.java:32)
        at com.atlassian.quartz.jobs.AbstractJob.executeInternal(AbstractJob.java:88)
        at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
        at org.quartz.core.JobRunShell.run(JobRunShell.java:199)
        at com.atlassian.confluence.schedule.quartz.ConfluenceQuartzThreadPool$1.run(ConfluenceQuartzThreadPool.java:20)
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:549)

This appears to be an issue still? We have a lot of links in our test documentation that are only valid if you are in the related test network. Apparently Confluence will still try and follow these links for some reason? I see a huge amount of these errors in our logs and Confluence is very unresponsive at times (this seems to be related). We are now at version 5.3.1.

2014-10-23 15:40:00,053 WARN [scheduler_Worker-5] [com.atlassian.trackback.DefaultTrackbackFinder] findPingUrls Error getting content of URL 'https://testserver/owa/': javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.ssl.Alerts.getSSLException(Unknown Source)
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source)
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source)
at sun.security.ssl.Handshaker.processLoop(Unknown Source)
at sun.security.ssl.Handshaker.process_record(Unknown Source)
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at sun.security.ssl.SSLSocketImpl.writeRecord(Unknown Source)
at sun.security.ssl.AppOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.flush(Unknown Source)

also interested in a solution of this issue

We are also experiencing this behavior with 2.10.1 and have tried to find the reason for our Confluence freezes for a while in

https://support.atlassian.com/browse/CSP-41112

Now we just found this issue and it looks exactly like what we see in our logfiles, and like this is the reason.

That error shouldn't leave an open connection, DB or otherwise.