[hudson-dev] Hudson Test results being loaded from disk

[Henrik Lynggaard Hansen <henrik@xxxxxxx>]

Hi

As discussed on todays call, Hudson does hold at least part of the
Test Result for a build behind a WeakReference which will get garbage
collected. So if someone like us creates a plugin which accesses it
frequently, it will get reloaded all the time.

Reloading is of course slow and causes request threads to hang. Here
is a example of a reload which happens when getResult finds a garbage
collected WeakReference


   java.lang.Thread.State: RUNNABLE
	at java.io.FileInputStream.readBytes(Native Method)
	at java.io.FileInputStream.read(FileInputStream.java:199)
	at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
	at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
	at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
	- locked <0x00002aab3e6dc4a0> (a java.io.InputStreamReader)
	at java.io.InputStreamReader.read(InputStreamReader.java:167)
	at java.io.BufferedReader.read1(BufferedReader.java:185)
	at java.io.BufferedReader.read(BufferedReader.java:261)
	- locked <0x00002aab3e6dc4a0> (a java.io.InputStreamReader)
	at org.xmlpull.mxp1.MXParser.fillBuf(MXParser.java:2992)
	at org.xmlpull.mxp1.MXParser.more(MXParser.java:3046)
	at org.xmlpull.mxp1.MXParser.parseProlog(MXParser.java:1410)
	at org.xmlpull.mxp1.MXParser.nextImpl(MXParser.java:1395)
	at org.xmlpull.mxp1.MXParser.next(MXParser.java:1093)
	at com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:109)
	at com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:148)
	at com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:141)
	at com.thoughtworks.xstream.io.xml.AbstractPullReader.move(AbstractPullReader.java:118)
	at com.thoughtworks.xstream.io.xml.AbstractPullReader.moveDown(AbstractPullReader.java:103)
	at com.thoughtworks.xstream.io.xml.XppReader.<init>(XppReader.java:63)
	at com.thoughtworks.xstream.io.xml.AbstractXppDriver.createReader(AbstractXppDriver.java:58)
	at com.thoughtworks.xstream.XStream.fromXML(XStream.java:894)
	at hudson.XmlFile.read(XmlFile.java:128)
	at hudson.tasks.junit.TestResultAction.load(TestResultAction.java:147)
	at hudson.tasks.junit.TestResultAction.getResult(TestResultAction.java:104)
	- locked <0x00002aab2c9d6b20> (a hudson.tasks.junit.TestResultAction)
                 <<<<<<<<<<<< Other request threads will wait for this
lock
	at hudson.tasks.junit.TestResultAction.getFailedTests(TestResultAction.java:138)
	at org.xxxxxxx.hudson.TestResult.getTestResults(TestResult.java:54)
                      <<<<<<<<<<<< this is our class calling hudson


Best regards
Henrik