Forum d'Aide de Forumcrea

N'hésitez pas à poser ici vos questions sur ForumCrea.

Vous n'êtes pas identifié.

#1 21-08-2017 13:52:34

Date d'inscription: 12-05-2017
Messages: 401

Calculating Maximum Consumption Rate (MCR)

1) Why MAXDOP=4 is specified while MCR tends to calculate consumption rate for 1 core?

Since the calculations is      ( [Logical reads] / [CPU time in seconds] ) * 8KB / 1024

and there is 1 second of [CPU time in seconds]  per second for each core, the result is in MB/Core/sec in any case.  But if you evaluated with a single-threaded query you might overestimate the MCR as the limiting factor in a multi-threaded query might be memory transfer bandwidth.  As Thomas said, this is somewhat arbitrary, and they could have picked 2 or 6 or 8.

>What if my processor uses 25% of its maximum power when running the test query?

Since MAXDOP is limited in calculating MCR it's not expected to use 100% of your available CPU resources.  And the query used to measure MCR is simple: in a real world workload queries may require significantly more CPU/MB than the benchmark query.  So if you have free CPU resources while performing simple scan-oriented queries, then you will have resources available to perform additional query processing while scanning at your maximum rate.

For more you can check

Data warehousing video

Hors ligne


Pied de page des forums

Créez Votre Propre Forum
Insérer vos Graphiques
Dictionnaires de Traduction
Hébergé par