NAME

       mongoc_basic_troubleshooting - Basic Troubleshooting

TROUBLESHOOTING CHECKLIST

       The following is a short list of things to check when you have a problem.

       • Did you call mongoc_init() in main()? If not, you will likely see a segfault.

       • Have you leaked any clients or cursors as can be found with mongoc-stat <PID>?

       • Have packets been delivered to the server? See egress bytes from mongoc-stat <PID>.

       • Does  valgrind  show  any  leaks?  Ensure  you  call mongoc_cleanup() at the end of your
         process to cleanup lingering allocations from the MongoDB C driver.

       • If compiling your own copy  of  MongoDB  C  Driver,  consider  using  the  cmake  option
         -DENABLE_TRACING=ON  to  enable  function  tracing  and  hex dumps of network packets to
         STDERR and STDOUT.

PERFORMANCE COUNTERS

       The MongoDB C driver comes  with  an  optional  unique  feature  to  help  developers  and
       sysadmins  troubleshoot  problems  in  production.  Performance counters are available for
       each process using the driver.  If available, the counters can be accessed outside of  the
       application process via a shared memory segment.  This means that you can graph statistics
       about your application process easily from tools like Munin or Nagios.  Your author  often
       uses watch --interval=0.5 -d mongoc-stat $PID to monitor an application.

       Performance  counters  are  only  available  on  Linux platforms and macOS arm64 platforms
       supporting shared memory segments.  On supported platforms they are  enabled  by  default.
       Applications   can   be  built  without  the  counters  by  specifying  the  cmake  option
       -DENABLE_SHM_COUNTERS=OFF. Additionally, if performance  counters  are  already  compiled,
       they can be disabled at runtime by specifying the environment variable MONGOC_DISABLE_SHM.

       Performance counters keep track of the following:

       • Active and Disposed Cursors

       • Active and Disposed Clients, Client Pools, and Socket Streams.

       • Number of operations sent and received, by type.

       • Bytes transferred and received.

       • Authentication successes and failures.

       • Number of wire protocol errors.

       To  access  counters for a given process, simply provide the process id to the mongoc-stat
       program installed with the MongoDB C Driver.

          $ mongoc-stat 22203
             Operations : Egress Total        : The number of sent operations.                    : 13247
             Operations : Ingress Total       : The number of received operations.                : 13246
             Operations : Egress Queries      : The number of sent Query operations.              : 13247
             Operations : Ingress Queries     : The number of received Query operations.          : 0
             Operations : Egress GetMore      : The number of sent GetMore operations.            : 0
             Operations : Ingress GetMore     : The number of received GetMore operations.        : 0
             Operations : Egress Insert       : The number of sent Insert operations.             : 0
             Operations : Ingress Insert      : The number of received Insert operations.         : 0
             Operations : Egress Delete       : The number of sent Delete operations.             : 0
             Operations : Ingress Delete      : The number of received Delete operations.         : 0
             Operations : Egress Update       : The number of sent Update operations.             : 0
             Operations : Ingress Update      : The number of received Update operations.         : 0
             Operations : Egress KillCursors  : The number of sent KillCursors operations.        : 0
             Operations : Ingress KillCursors : The number of received KillCursors operations.    : 0
             Operations : Egress Msg          : The number of sent Msg operations.                : 0
             Operations : Ingress Msg         : The number of received Msg operations.            : 0
             Operations : Egress Reply        : The number of sent Reply operations.              : 0
             Operations : Ingress Reply       : The number of received Reply operations.          : 13246
                Cursors : Active              : The number of active cursors.                     : 1
                Cursors : Disposed            : The number of disposed cursors.                   : 13246
                Clients : Active              : The number of active clients.                     : 1
                Clients : Disposed            : The number of disposed clients.                   : 0
                Streams : Active              : The number of active streams.                     : 1
                Streams : Disposed            : The number of disposed streams.                   : 0
                Streams : Egress Bytes        : The number of bytes sent.                         : 794931
                Streams : Ingress Bytes       : The number of bytes received.                     : 589694
                Streams : N Socket Timeouts   : The number of socket timeouts.                    : 0
           Client Pools : Active              : The number of active client pools.                : 1
           Client Pools : Disposed            : The number of disposed client pools.              : 0
               Protocol : Ingress Errors      : The number of protocol errors on ingress.         : 0
                   Auth : Failures            : The number of failed authentication requests.     : 0
                   Auth : Success             : The number of successful authentication requests. : 0

SUBMITTING A BUG REPORT

       Think you've found a bug? Want to see a new feature in the MongoDB C driver? Please open a
       case in our issue management tool, JIRA:

       • Create an account and login.

       • Navigate to the CDRIVER project.

       • Click Create Issue - Please provide as much information as possible about the issue type
         and how to reproduce it.

       Bug reports in JIRA for all driver projects (i.e. CDRIVER,  CSHARP,  JAVA)  and  the  Core
       Server (i.e. SERVER) project are public.

AUTHOR

       MongoDB, Inc

COPYRIGHT

       2017-present, MongoDB, Inc