Informix

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  • 1.  DIRECT_IO for Informix 14.10FC8

    Posted Wed June 22, 2022 10:43 AM
    I see that with Informix 14.10FC8 we have a somewhat different onconfig explanation for the DIRECT_IO that what was used for Informix 12.10.FC10AEE:

    New:
    # DIRECT_IO - Set of flags that may be combined to control "special" I/O
    # 0x0 = Neither direct I/O nor concurrent I/O is used
    # 0x1 = Direct I/O is used if available
    # 0x2 = Concurrent I/O is enabled (on AIX operating systems)
    # 0x4 = Special I/O is enabled for TEMP DBspaces
    ###################################################################

    Old:
    # DIRECT_IO - Specifies whether direct I/O is used for cooked
    # files used for dbspace chunks.
    # Acceptable values are:
    # 0 Disable
    # 1 Enable direct I/O
    # 2 Enable concurrent I/O
    ###################################################################

    If I had set DIRECT_IO to 1 before, should I leave it as 1? Or should I change it to "0x1" for 14.10FC8?

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    John Dargan
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    #Informix


  • 2.  RE: DIRECT_IO for Informix 14.10FC8

    IBM Champion
    Posted Wed June 22, 2022 10:51 AM
    John:

    All numeric ONCONFIG parameter values can always be supplied either in decimal or hex (preceded by 0x), so either way is fine. The description was changed to make it a bit clearer that the values are bits so you can enable DIRECT_IO that includes temp dbspaces on Linux by setting it to 5 or 0x5 and on AIX be setting it to 6 or 0x6. (Only the Deity knows what the engine does if you set 0x3 or 0x7.) 

    B^)

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    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
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