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kdb

What's # after a field name in HDB

I see in one partition. There are many fields in that date. eg. sym, age, height, colour, money.

However, I see this in the partition (sym, age, age# , height ...etc) and age# has large volume of data.

What does # mean here?

Solution

  • https://code.kx.com/q4m3/14_Introduction_to_Kdb%2B/#1423-splayed-tables-with-nested-columns

    Observe that there are two files associated with the compound column – namely, c and c#. If you examine these files you will discover that the “sharp” file contains the binary data of the original list in flattened form and the non-sharp file is a serialized q list of integers representing the lengths of each sublist of the original list.