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  1. Jenkins
  2. JENKINS-60625

Dashboard rendering blocked on UpdateSite.getJSONObject

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    • Jenkins 2.212

    Description

      Recently I have noticed Jenkins page rendering being blocked for a long time (sometimes nearly 30s) with stack traces such as

      "Handling GET /jenkins/ from ... : ... View/index.jelly AdministrativeMonitorsDecorator/footer.jelly" ...
         java.lang.Thread.State: RUNNABLE
      	at java.lang.String.<init>(String.java:207)
      	at java.lang.String.substring(String.java:1933)
      	at net.sf.json.util.JSONTokener.matches(JSONTokener.java:110)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:912)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:348)
      	at net.sf.json.JSONArray._fromJSONTokener(JSONArray.java:1131)
      	at net.sf.json.JSONArray.fromObject(JSONArray.java:125)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:351)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:955)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:348)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:955)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:348)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:955)
      	at net.sf.json.JSONObject._fromString(JSONObject.java:1145)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:162)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:132)
      	at hudson.model.UpdateSite.getJSONObject(UpdateSite.java:338)
      	at hudson.model.UpdateSite.getData(UpdateSite.java:323)
      	at hudson.model.UpdateCenter.getCoreSource(UpdateCenter.java:604)
      	at hudson.model.UpdateCenter$CoreUpdateMonitor.getData(UpdateCenter.java:1035)
      	at hudson.model.UpdateCenter$CoreUpdateMonitor.isActivated(UpdateCenter.java:1030)
      	at jenkins.model.Jenkins.lambda$getActiveAdministrativeMonitors$0(Jenkins.java:2183)
      	at jenkins.model.Jenkins$$Lambda$103/1298422401.test(Unknown Source)
      	at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174)
      	at java.util.Iterator.forEachRemaining(Iterator.java:116)
      	at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
      	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
      	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
      	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
      	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
      	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:566)
      	at jenkins.model.Jenkins.getActiveAdministrativeMonitors(Jenkins.java:2188)
      	at jenkins.management.AdministrativeMonitorsDecorator.getActiveAdministrativeMonitors(AdministrativeMonitorsDecorator.java:77)
      	at jenkins.management.AdministrativeMonitorsDecorator.getActiveAdministrativeMonitorsCount(AdministrativeMonitorsDecorator.java:72)
      	at jenkins.management.AdministrativeMonitorsDecorator.shouldDisplay(AdministrativeMonitorsDecorator.java:131)
      

      or

        java.lang.Thread.State: RUNNABLE
      	at java.util.regex.Pattern.compile(java.base@11.0.5/Pattern.java:1757)
      	at java.util.regex.Pattern.<init>(java.base@11.0.5/Pattern.java:1428)
      	at java.util.regex.Pattern.compile(java.base@11.0.5/Pattern.java:1068)
      	at net.sf.json.regexp.JdkRegexpMatcher.<init>(JdkRegexpMatcher.java:38)
      	at net.sf.json.regexp.JdkRegexpMatcher.<init>(JdkRegexpMatcher.java:31)
      	at net.sf.json.regexp.RegexpUtils.getMatcher(RegexpUtils.java:39)
      	at net.sf.json.util.JSONTokener.matches(JSONTokener.java:111)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:912)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:348)
      	at net.sf.json.JSONArray._fromJSONTokener(JSONArray.java:1131)
      	at net.sf.json.JSONArray.fromObject(JSONArray.java:125)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:351)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:955)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:348)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:955)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
      	at net.sf.json.util.JSONTokener.nextValue(JSONTokener.java:348)
      	at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:955)
      	at net.sf.json.JSONObject._fromString(JSONObject.java:1145)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:162)
      	at net.sf.json.JSONObject.fromObject(JSONObject.java:132)
      

      While loading the JSON text from disk takes just milliseconds, the parsing is extremely slow (hundreds of times slower than jq, for example). This seems to be due to poor code in json-lib, especially this which repeatedly compiles patterns where a simple .startsWith("null") would apparently have sufficed!

      The poor performance of JSONObject.fromObject might not have been so noticeable except that some administrative monitors blocked on the parsing, contrary to the Javadoc in AdministrativeMonitor.isActivated.

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            jglick Jesse Glick added a comment -

            Note that I am still inclined to look for ways to patch or bypass this library to minimize even background CPU, but that would be tracked as a separate issue and presumably not be an LTS candidate.

            jglick Jesse Glick added a comment - Note that I am still inclined to look for ways to patch or bypass this library to minimize even background CPU, but that would be tracked as a separate issue and presumably not be an LTS candidate.

            I would like to give this change some more soaking time so postponing to 2.204.3

             

            olivergondza Oliver Gondža added a comment - I would like to give this change some more soaking time so postponing to 2.204.3  

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              jglick Jesse Glick
              jglick Jesse Glick
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                Updated:
                Resolved: