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memory error while executing query

  • 1.  memory error while executing query

    Posted 27 days ago
    Edited by Nagulan Santhi 26 days ago
    Hi 

    its giving error as 
    level=error msg="Unable to process the queryTMapDException({ErrorMsg:Exception: Not enough host memory to execute the query})"
    time="2019-11-14T14:03:02+05:30" level=error msg="error running client:TMapDException({ErrorMsg:Exception: Not enough host memory to execute the query})"

    do we need to increase some memory size in mapd or due to some watchdog issue
    #Core
    #Immerse


  • 2.  RE: memory error while executing query

    Posted 27 days ago
    Hi @Omnisci user

    the second query is being stopped because for each group (customer), the executor needs to allocate a bitmap to compute the count distinct, so assuming you have a lot of customers, the memory required is going to be quite large.
    amnyway the count distinct on rowid is needed when you are going to compute aggregations joining different tables, that has a different cardinality, so the second query is going to return the worng data.
    On a different topic, have you tried to enable the parameter null-div-by-zero? I think that performance wise is better than using the CASE statement.