Bug fixing

Bug fixing

Lesson 1:
In the program, Some threads are designed to run forever until program is shutdown, but unfortunately, they didn't capture all-possibly-thrown exceptions,
and this would cause thread exit unexpectedly.

Lesson 2: When program runs slowly or weirdly, check system status, and all possibility, and guess reasonably.


Some tests defects look very weird, the program can not send out multicast messages intermittently. At first, I guess it may be code problem, or because we have upgraded machine
to new operating system, new JDK, so maybe new OS or new JDK is the culprit. when I do test, I found that when I hit the problem, the command 'java -version' would hang for ever. But at that moment, I ignore this obvious information.
At last my colleague figure out the root cause of the problem, that is because one process in the machine consumes too many system resource,
which cause all other processes to starve and frozen, and run extremely slow.
UID PID PPID C STIME TTY TIME CMD
root 307694 1 50 15:14:20 - 33:08 /process_cmd
C

(-f, l, and -l flags) CPU utilization of process or thread, incremented each time the system clock ticks and the process or thread is found to be running. The value is decayed by the scheduler by dividing it by 2 once per second.
For the sched_other policy, CPU utilization is used in determining process scheduling priority. Large values indicate a CPU intensive process and result in lower process priority whereas small values indicate an I/O intensive process and result in a more favorable priority.

How stupidly I didn't use ps and top command to check system run status, and ignore when I discover 'java -version' hang, and didn't catch the connection.


Post a Comment

Labels

Java (159) Lucene-Solr (112) Interview (61) All (58) J2SE (53) Algorithm (45) Soft Skills (38) Eclipse (33) Code Example (31) Linux (25) JavaScript (23) Spring (22) Windows (22) Web Development (20) Tools (19) Nutch2 (18) Bugs (17) Debug (16) Defects (14) Text Mining (14) J2EE (13) Network (13) Troubleshooting (13) PowerShell (11) Chrome (9) Design (9) How to (9) Learning code (9) Performance (9) Problem Solving (9) UIMA (9) html (9) Http Client (8) Maven (8) Security (8) bat (8) blogger (8) Big Data (7) Continuous Integration (7) Google (7) Guava (7) JSON (7) Shell (7) ANT (6) Coding Skills (6) Database (6) Lesson Learned (6) Programmer Skills (6) Scala (6) Tips (6) css (6) Algorithm Series (5) Cache (5) Dynamic Languages (5) IDE (5) System Design (5) adsense (5) xml (5) AIX (4) Code Quality (4) GAE (4) Git (4) Good Programming Practices (4) Jackson (4) Memory Usage (4) Miscs (4) OpenNLP (4) Project Managment (4) Spark (4) Testing (4) ads (4) regular-expression (4) Android (3) Apache Spark (3) Become a Better You (3) Concurrency (3) Eclipse RCP (3) English (3) Happy Hacking (3) IBM (3) J2SE Knowledge Series (3) JAX-RS (3) Jetty (3) Restful Web Service (3) Script (3) regex (3) seo (3) .Net (2) Android Studio (2) Apache (2) Apache Procrun (2) Architecture (2) Batch (2) Bit Operation (2) Build (2) Building Scalable Web Sites (2) C# (2) C/C++ (2) CSV (2) Career (2) Cassandra (2) Distributed (2) Fiddler (2) Firefox (2) Google Drive (2) Gson (2) How to Interview (2) Html Parser (2) Http (2) Image Tools (2) JQuery (2) Jersey (2) LDAP (2) Life (2) Logging (2) Python (2) Software Issues (2) Storage (2) Text Search (2) xml parser (2) AOP (1) Application Design (1) AspectJ (1) Chrome DevTools (1) Cloud (1) Codility (1) Data Mining (1) Data Structure (1) ExceptionUtils (1) Exif (1) Feature Request (1) FindBugs (1) Greasemonkey (1) HTML5 (1) Httpd (1) I18N (1) IBM Java Thread Dump Analyzer (1) JDK Source Code (1) JDK8 (1) JMX (1) Lazy Developer (1) Mac (1) Machine Learning (1) Mobile (1) My Plan for 2010 (1) Netbeans (1) Notes (1) Operating System (1) Perl (1) Problems (1) Product Architecture (1) Programming Life (1) Quality (1) Redhat (1) Redis (1) Review (1) RxJava (1) Solutions logs (1) Team Management (1) Thread Dump Analyzer (1) Visualization (1) boilerpipe (1) htm (1) ongoing (1) procrun (1) rss (1)

Popular Posts