4 Replies Latest reply on Oct 16, 2015 7:29 AM by shawkins

    GC overhead limit exceeded,Java heap space

    jietao

      Hi,

       

      I test my VDB to a MySQL database using the Eclipse SQL Scrapbook in terms of the Teiid designer. As I run select * from sometable, I got such result:

      GC overhead limit exceeded (or java heap space)

      Elapsed Time:  0 hr, 0 min, 0 sec, 0 ms.

       

      I do not have any message in the error log. In the gc.log.0.current file of the Teiid server stays:

      2015-10-15T14:30:39.589+0200: 18540,062: [GC (Allocation Failure) [PSYoungGen: 334560K->352K(396288K)] 821276K->487068K(1286656K), 0,0055430 secs] [Times: user=0,02 sys=0,01, real=0,00 secs]

       

      Solution?

        • 1. Re: GC overhead limit exceeded,Java heap space
          shawkins

          > Solution?


          Unfortunately there is not enough to make any determination of what is happening.  At least a query plan is needed.  Ideally you could provide some analysis of a heap dump to show what is mostly occupying the heap.

          • 2. Re: GC overhead limit exceeded,Java heap space
            jaysensharma

            The "GC overhead limit exceeded " indicates that, more than 98% of the total time is spent doing garbage collection and less than 2% of the heap is recovered.


            The "GC overhead limit exceeded " in general represent the following cause:

                1. When the heap is too small, there is a memory leak.  (Try increasing the -Xmx value while starting your process)

                 2. The old generation size of the heap might be very small compared to the new generation.

                3. If increasing the Heap size (-Xmx)  OR tuning the Old Generation size does not help then it might be a memory leak in the application code/container code.

            • 3. Re: GC overhead limit exceeded,Java heap space
              jietao

              Thx. The reason is that our database table is too big and I cannot select *. Thank you all.

              • 4. Re: GC overhead limit exceeded,Java heap space
                shawkins

                Is there other processing going on here?  A simple forward only result will be batched to the client so that it would have a negligible memory overhead.