http://www.firstderivatives.com/downloads/q\_for\_Gods\_Dec\_2012.pdf
I am reading page 10 of this. I have a lot of partitions and segments. Should I use s#sym or p#sym? Which of the following is/are true?
select from quote where sym in (AAAAAB… 1% symbols)
A. With the sorted attribute, kdb runs binary search and random seek for each partition to find the data for each of the symbols in the query
B. The parted attribute lookup table maps each unique symbol value to its first appearance within each partition.
C. The parted attribute lookup table is persisted WITHIN the sym column within each partition.
D. The parted attribute lookup table is persisted IN A SEPARATE FILE next to the sym column within each partition.
E. The parted attribute lookup table is rebuilt every time the database is loaded.
F. The parted attribute lookup table is rebuilt every time each partition is queried.
G. To rebuilt the parted attribute lookup table, full sequential scan is required on the sym column on each partition.
a_11
2
On Monday, March 23, 2015 at 3:25:21 AM UTC-4, Yan Yan wrote:
http://www.firstderivatives.com/downloads/q_for_Gods_Dec_2012.pdf
I am reading page 10 of this. I have a lot of partitions and segments. Should I use s#sym or p#sym?
You should use `p#
Which of the following is/are true?
A, B, C, and G.
select from quote where sym in (AAAAAB… 1% symbols)
A. With the sorted attribute, kdb runs binary search and random seek for each partition to find the data for each of the symbols in the query
B. The parted attribute lookup table maps each unique symbol value to its first appearance within each partition.
C. The parted attribute lookup table is persisted WITHIN the sym column within each partition.
D. The parted attribute lookup table is persisted IN A SEPARATE FILE next to the sym column within each partition.
E. The parted attribute lookup table is rebuilt every time the database is loaded.
F. The parted attribute lookup table is rebuilt every time each partition is queried.
G. To rebuilt the parted attribute lookup table, full sequential scan is required on the sym column on each partition.
http://www.timestored.com/kdb-guides/table-attributes#parted-attribute
> As demonstrated `p# is not preserved even during appends that would meet the requirements
Which of the following is/are true?
H. The lookup table is stored in the head of the `p#sym column file
I. The `p#sym is not preserved on appends due to the fact it is stored in the head of the file
J. The lookup table is sequentially read when each partition is queried
K. The lookup table is sequentially read when each partition is mmap’d