April 2, 2002 at 8:26 pm
Hi,
What does the estimated row size mean in the execution plan? The row count is displayed above showing the number of rows returned.
Thanks,
Stan
April 4, 2002 at 8:22 pm
Basically this represents the rows returned thru that operator based on thru datatypes and I believe a header of some kind. Anyway these are the notes I have made in testing.
select cast(pkid as smallint) from tbl_ccid_drop
/*
char 4 = 11, 10 = 17 ----Move whole numbers, base of 9 for 1, 2=9 then add
1 for each number after 2
nchar 1 = 9, 2 = 11, 3 = 13 ---Same as char except nchars take double byte
space.
varchar 4 = 13, 10 = 16 ---Base 11, 1=11, 2=12, 3=12, divide number by 2
and drop remainder
nvarchar 2 = 13, 3 = 14, 4 = 15 --Base 11, really same as varchar except
number take double space.
int = 11
smallint = 9 (7 overhead for datatype)
tinyint = 9 (8 overhead for datatype)
decimal (4,2)=12, (10,2) = 16, (24,2) = 20, (24,23) = 20 -- same for
numeric
float (4,2)=15, (10,2) = 15, (24,2) = 15, (24,23) = 15 (7 is the overhead)
datetime = 15 (7 overhead by self)
smalldatetime = 11
sysname = 139 (7 overhead for datatype)
timestamp = 15, with 2 output same this doubles - 7 (so that makes 15 - 7
= 8 without counting overhead)
*/
This may not make sense and I am working on an article to discuss this since I have done so much.
"Don't roll your eyes at me. I will tape them in place." (Teacher on Boston Public)
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