jython load 高的分析

登录到s4发现load很高，cpu完全是被jython占用，发现启jstack主要被三种线程占用：
1. memcached
2. perf/models.py:30,next_blog_id(),prev_blog_id()这个地方绝对有性能问题导致mysql被lock。
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at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189)
        - locked <0x0000000778151558> (a com.mysql.jdbc.util.ReadAheadInputStream)
        at django.db.models.query$py._result_iter$8(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/Lib/site-packages/django/db/models/query.py:99)
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3. 抛出的异常打印stack可能会非常耗时：
{code}
   java.lang.Thread.State: RUNNABLE
        at java.lang.Throwable.fillInStackTrace(Native Method)
        at java.lang.Throwable.fillInStackTrace(Throwable.java:782)
        - locked <0x000000074c3389a8> (a org.python.core.PyException)
{code}


{code}
        at django.db.models.query$py.call_function(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/Lib/site-packages/django/db/models/query.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:165)
        at org.python.core.PyGenerator.__iternext__(PyGenerator.java:149)
        at org.python.core.PyGenerator.__iternext__(PyGenerator.java:131)
        at perf.models$py.get_recs$1(/data1/duitang/dist/app/test/jython/duitang/../duitang/perf/models.py:30)
        at perf.models$py.call_function(/data1/duitang/dist/app/test/jython/duitang/../duitang/perf/models.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:165)
        at org.python.core.PyBaseCode.call(PyBaseCode.java:166)
        at org.python.core.PyFunction.__call__(PyFunction.java:368)
        at message.models$py.fetch_pre_blog$66(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/duitang/message/models.py:723)
        at message.models$py.call_function(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/duitang/message/models.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:165)
        at org.python.core.PyBaseCode.call(PyBaseCode.java:134)
        at org.python.core.PyFunction.__call__(PyFunction.java:347)
        at org.python.core.PyMethod.__call__(PyMethod.java:109)
        at message.models$py.get_prev_blog$65(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/duitang/message/models.py:709)
        at message.models$py.call_function(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/duitang/message/models.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:165)
        at org.python.core.PyBaseCode.call(PyBaseCode.java:134)
        at org.python.core.PyFunction.__call__(PyFunction.java:347)
        at org.python.core.PyMethod.__call__(PyMethod.java:109)
        at message.models$py.prev_blog_id$64(/duitang/dist/sys/tomcat/webapps/ROOT/WEB-INF/lib-python/duitang/message/models.py:701)

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