INSERT /*+ direct */

Hi ,



INSERT /*+ direct */ into Table Writes the data directly to disk (ROS) bypassing memory (WOS).


Please tell me the advantage & disadvantage of this.


If in my system the RAM is less then can I insert always using /*+direct*/.


Please give me some more details.


  • Options

    The advantage is on how Vertica treats your data since there is limitation in your ROS containers as per table, and that is 1024 !!!

     With the help of WOS the margeout process will run with less stress that if you do data loads with direct option (direct to ROS).

     ROS limitation is quite a bitch :) when trying to do close to real time analitics. 

    Also the data stored in WOS is not sorted , indexed or any type of commpression on it.

     You can insert only with direct if you want but this depends on the frequency you do it. All must be orchesrated by tunning your database parameters for mergouts so you won't fall into TO MANY ROS containers error.



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