Green-IT und Datenbanken - ODBMS

6 Energieoptimierungen
114
Relative Kosten = 107132418
Abfrageplan
Call module B, which populates temp-file A.
Call module F, which populates temp-file C.
Read temp-file C, looping on count(PS_SUPPKEY), %SQLUPPER(P_BRAND),
%SQLUPPER(P_TYPE), P_SIZE, and a counter.
For each row:
Output the row.
module B
Read index map SQLUser.PART.PSIZEIDX, looping on P_SIZE (with a given set of values) and
ID.
For each row:
Read master map SQLUser.PART.PARTPRIMARYIDX, using the given idkey value.
Read master map SQLUser.PARTSUPP.PARTSUPPPRIMARYIDX, using the given PS_PARTKEY,
and looping on PS_SUPPKEY.
For each row:
Check distinct values for %SQLUPPER(P_BRAND), P_SIZE, and %SQLUPPER(P_TYPE)
using temp-file A,
subscripted by a hashing of these values.
For each distinct row:
Add a row to temp-file A, subscripted by the hashing,
with node data of P_SIZE, %SQLUPPER(P_TYPE), %SQLUPPER(P_BRAND), and
PS_SUPPKEY.
Check distinct values for %SQLUPPER(P_BRAND), P_SIZE, %SQLUPPER(P_TYPE), and
PS_SUPPKEY using a temp-file.
For each distinct row:
Update the accumulated count(PS_SUPPKEY) in temp-file A,
subscripted by the hashing.
module F
Read temp-file A, looping on the hashing subscript.
For each row:
Add a row to temp-file C, subscripted by count(PS_SUPPKEY), %SQLUPPER(P_BRAND),
%SQLUPPER(P_TYPE), P_SIZE, and a counter,
with node data of [expression] and [expression].
subquery
Read master map SQLUser.SUPPLIER.SUPPLIERPRIMARYIDX, using the given idkey value
Abbildung 6.15: Abfrageplan TPC-H Abfrage 16 mit zusätzlichem Index.