On 04/06/11 09:36, Hendrik Woltersdorf wrote:
>
> Hi,
>
> I query ndbinfo.diskpagebuffer for hitratio as shown in
>
> http://dev.mysql.com/doc/mysql-cluster-excerpt/5.1/en/mysql-cluster-ndbinfo-diskpagebuffer.html
>
> In different clusters I get a different number of rows per node-id
> depending on the number of "block_instance"s per node-id.
>
> This column (block_instance) is not really documented for table
> diskpagebuffer. What does it mean here and is this information of any value
> for me?
>
> regards
>
> Hendrik Woltersdorf
> XCOM AG
> Email: Hendrik.Woltersdorf@stripped
In the multi-threaded data-node,
there are multiple instance of the disk-page-buffer-cache.
the "block_instance" show from which instance the numbers reported are.
> is this information of any value for me
i'd say no...
however, the suggested select to get hit-ratio, on link you provided
should be changed, to perform a group by node_id
e.g
SELECT node_id, 100 * SUM(page_requests_direct_return) / SUM(page_requests_direct_return +
page_requests_wait_io) AS hit_ratio
FROM ndbinfo.diskpagebuffer
GROUP BY node_id
/Jonas
>
>
> *** XCOM AG Legal Disclaimer ***
>
> Diese E-Mail einschliesslich ihrer Anhaenge ist vertraulich und ist allein
> für den Gebrauch durch den vorgesehenen Empfaenger bestimmt. Dritten ist
> das Lesen, Verteilen oder Weiterleiten dieser E-Mail untersagt. Wir bitten,
> eine fehlgeleitete E-Mail unverzueglich vollstaendig zu loeschen und uns
> eine Nachricht zukommen zu lassen.
>
> This email may contain material that is confidential and for the sole use
> of the intended recipient. Any review, distribution by others or forwarding
> without express permission is strictly prohibited. If you are not the
> intended recipient, please contact the sender and delete all copies.
>
> Hauptsitz: Bahnstrasse 37, D-47877 Willich, USt-IdNr.: DE 812 885 664
> Kommunikation: Telefon +49 2154 9209-70, Telefax +49 2154 9209-900,
> www.xcom.de
> Handelsregister: Amtsgericht Krefeld, HRB 10340
> Vorstand: Matthias Albrecht, Dirk Franzmeyer, Dr. Rainer Fuchs, Marco
> Marty, Dirk Werner
> Vorsitzender des Aufsichtsrates: Stefan H. Tarach
