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I just read about physical design and database adjustment and could not understand the concept of overhead, and consequently could not understand what the author of the book wanted to explain.
I understand previously by overhead as being a overload or superscript.
Author of the book.
The removal and creation of new indices is a overhead which may be justified in relation to improvements in performance.
I understand and made me seem coherent that the creation of indexes in the tables, helps in the speed of the queries made in it, but I do not understand how the opposite (the removal of indexes) helps in performance, as the author states.
Remarks
In this reply the author states that it does not matter much the context in which the word is used, in my context proceeds this reply?
If the community understands that my question can be answered by the above-mentioned answer, then I will remove it.
Book: Database systems, 2011. Elmasri R, Nevathe B, Cap 20, pg 495.
Overhead has nothing to do (directly) with superscript. But superscript can cause a overhead
– Jefferson Quesado
Indexes help in searches but can worsen operations of Insert, update or delete because it has associated constrains (checks roughly) this generates a further processing (overhead).
– rray
Constraints generate more processing and more processing can be translated or interpreted as overhead? is that @rray? in this case the removal of any index that is causing this increased processing, can suffer direct influence of these restrictions, if that is what I think I understood.
– Jonathas B. C.
Any processing beyond trivial is overhead. In case, check if a column is non-null generates a processing beyond insertion
– Jefferson Quesado
I usually translate as "overweight" or "extra weight". "Overload" already exists and means something else in the context of programming.
– Pablo Almeida