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Update segments.md (#8693) 

Make bullet numbers clearer with parantheses, fix last reference to 2 being interpreted as a bullet point.
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Jad Naous 2019-10-17 11:55:23 -07:00 committed by Fangjin Yang
parent 75527f09cd
commit d54d2e1627
1 changed files with 4 additions and 4 deletions
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docs/design/segments.md
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@ -67,13 +67,13 @@ three data structures:
Why these three data structures? The dictionary simply maps string
values to integer ids so that the values in 2 and 3 can be
represented compactly. The bitmaps in 3 -- also known as *inverted
values to integer ids so that the values in \(2\) and \(3\) can be
represented compactly. The bitmaps in \(3\) -- also known as *inverted
indexes* allow for quick filtering operations (specifically, bitmaps
are convenient for quickly applying AND and OR operators). Finally,
the list of values in 2 is needed for *group by* and *TopN*
the list of values in \(2\) is needed for *group by* and *TopN*
queries. In other words, queries that solely aggregate metrics based
on filters do not need to touch the list of dimension values stored in 2.
on filters do not need to touch the list of dimension values stored in \(2\).
To get a concrete sense of these data structures, consider the ‘page’
column from the example data above. The three data structures that