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Attributes memory overhead
Out of curiosity, can anyone explain the attributes overhead as explained in the Abridged Q Language Manual? Does anyone know what the 4*u+1 is? for parted and grouped? (I know the 4byte should be probably 8 bytes after 3.0)
example overhead
`s#2 2 3 sorted 0
`u#2 4 5 unique 16*u
`p#2 2 1 parted (4*u;16*u;4*u+1)
`g#2 1 2 grouped (4*u;16*u;4*u+1;4*n)The byte overheads use n(number of elements) and u(number of uniques). These are used by lookups, e.g.
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1 Reply
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You might find this document useful: https://dataintellect.com/blog/adventure-in-retrieving-memory-size-of-kdb-object/ It covers the memory need of attributes.
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