Informix

CDC through connection managers

  • 1.  CDC through connection managers

    Posted 25 days ago

    Hi!

    We have recently tested a product called QDI (or Qlik Replicate) from Qlik for consuming log data from an Informix instance through CDC. When making a direct connection to on specific server this works without issues (apart from some limitations in Informix CDC). However, since our instance is part of an HDR cluster, and we normally connect to it using a group of connection managers, we wanted to utilize the connection managers (or, at least one connection manager during the first test) for redirecting the CDC session to the current primary server.

    While the connection seems to work, the first CDC api command, cdc_opensess(), fails with error code -83721:
    00007348: 2021-05-19T10:41:52:602897 [SOURCE_CAPTURE ]I: Connected (informix_endpoint_esql.c:1349)
    00007348: 2021-05-19T10:41:52:602897 [SOURCE_CAPTURE ]T: open cdc api session: recs per read: 256, bytes per read: 131072, poll interval: 5 (informix_endpoint_capture.c:299)
    00007348: 2021-05-19T10:41:52:603896 [SOURCE_CAPTURE ]I: CDC_OPENSESS for server grp_hist_oltp Timeout 0 Max read recs 256 (informix_endpoint_esql.c:1458)
    00007348: 2021-05-19T10:41:52:604895 [SOURCE_CAPTURE ]T: cdc_opensess retval = -83721 (informix_endpoint_esql.c:1487)Error in 'cdc_opensess': API retval = -83721, CDC error = 'UNKNOWN' (informix_endpoint_esql.c:1491)


    It took a while before I found the meaning of this error, apparently this is 

    CDC_E_ARG1 The first parameter passed to the function is not valid.

    According to the API documentation the first parameter is the server name:

    >>-cdc_opensess--(--"--server_name--"--,--session_ID--,--timeout--,-->
    
    >--max_recs--,--major_version--,--minor_version--)-------------><


    Now is the question, is this a problem/limitation with Informix CDC, or is it with Qlik Replicate? Have anyone utilized CDC in combination with a connection manager?



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    Øyvind Gjerstad
    Developer/Architect
    PostNord AS
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