RE: Stairway To SQL Server Columnstore Indexes Level 2: Columnstore Storage

Old Hand

Points: 378

May 6, 2017 at 11:18 am

#1941429

Hi Hugo;

I am sorry to get into this late. SQL Server 2016 became smarter with regards to Segment reading. Have a look at this below. I know you have already observed this but SQL Server 2014 and 2012 do not specify Segments read and those skipped but only dwell on Logical reads for you to determine if there are skipped Segments:

(1 row(s) affected)
Table 'FactOnlineSales'. Scan count 8, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 8468, lob physical reads 1, lob read-ahead reads 0.
Table 'FactOnlineSales'. Segment reads 9, segment skipped 6.
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)
Table 'FactOnlineSales'. Scan count 8, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 4282, lob physical reads 0, lob read-ahead reads 0.
Table 'FactOnlineSales'. Segment reads 5, segment skipped 10.
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.