[Yanel-dev] Unnecessary LOCKING at Resource instantiation

[Michael Wechner]

Hi Balz

If I understand correctly this happens at

src/core/java/org/wyona/yanel/core/util/ConfigurationUtil.java

or more particular in the DocumentBuilderFactory of xerces:

             Document doc = null;
             DocumentBuilderFactory dbf = 
javax.xml.parsers.DocumentBuilderFactory.newInstance();
             dbf.setNamespaceAware(true);
             javax.xml.parsers.DocumentBuilder parser = 
dbf.newDocumentBuilder();

I am not sure what this code is doing exactly. Maybe upgrading Xerces or 
replacing Xerces helps.

Let me know in case you will have found a way it improve this.

All the best

Michael

Am 29.04.20 um 09:38 schrieb basZero:
> Hi,
>
> today I noticed the following bottleneck in Yanel's implementation:
>
> for each request, the resource gets instantiated. and for each 
> request, the resource config XML gets parsed. During this parsing, 
> obviously something requires a Java System Property to be read, and 
> this access obviously gets synchronized, which is VERY bad for 
> concurrency.
>
> We have about 90 requests per second at peak time, and this is now our 
> next bottleneck (many others have been eliminated in the past).
>
> Here is the stack trace. Any idea, what exactly gets parsed here and why?
> I will optimize this code in my own Yanel branch and get rid of it 
> (e.g. permanent caching of resource config would help a lot).
>
> |"http-bio-443-exec-6766" #10541 daemon prio=5 os_prio=0 
> tid=0x00007f970d2bb800 nid=0x6ccf waiting for monitor entry 
> [0x00007f9590c4c000] java.lang.Thread.State: BLOCKED (on object 
> monitor) at java.util.Hashtable.get(Hashtable.java:362) - waiting to 
> lock <0x00000001806b31b0> (a java.util.Properties) at 
> java.util.Properties.getProperty(Properties.java:969) at 
> java.lang.System.getProperty(System.java:720) at 
> org.apache.xerces.parsers.SecuritySupport$4.run(Unknown Source) at 
> java.security.AccessController.doPrivileged(Native Method) at 
> org.apache.xerces.parsers.SecuritySupport.getSystemProperty(Unknown 
> Source) at 
> org.apache.xerces.parsers.ObjectFactory.createObject(Unknown Source) 
> at org.apache.xerces.parsers.ObjectFactory.createObject(Unknown 
> Source) at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source) 
> at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source) at 
> org.apache.xerces.jaxp.DocumentBuilderImpl.<init>(Unknown Source) at 
> org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.newDocumentBuilder(Unknown 
> Source) at 
> org.wyona.yanel.core.util.ConfigurationUtil.getCustomConfiguration(ConfigurationUtil.java:170) 
> at 
> org.wyona.yanel.core.ResourceConfiguration.load(ResourceConfiguration.java:194) 
> at 
> org.wyona.yanel.core.ResourceConfiguration.<init>(ResourceConfiguration.java:69) 
> at 
> org.wyona.yanel.core.ResourceTypeMatcherV1ImplV2.getResourceConfiguration(ResourceTypeMatcherV1ImplV2.java:66) 
> at 
> org.wyona.yanel.core.ResourceManager.getResource(ResourceManager.java:138) 
> at 
> org.wyona.yanel.servlet.YanelServlet.getResource(YanelServlet.java:1108) 
> at 
> org.wyona.yanel.servlet.YanelServlet.getContent(YanelServlet.java:608) 
> at org.wyona.yanel.servlet.YanelServlet.doGet(YanelServlet.java:530) 
> at org.wyona.yanel.servlet.YanelServlet.service(YanelServlet.java:414) 
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)|
>

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