maxdb primary key range accesses, selectivity XXX

[Former Member]

Hello gurus,

I need an help regarding this signal I have on my maxdb of an ERP production.

The external analysis tool from DB50 shows with a RED ALERT

hoch Selects and fetches selectivity 0.01%: 46300 selects and fetches, 1179127082 rows read, 69556 rows qualified.

Do not understand what is the problem.

How could I solve it in the case?

Do I have to run a checkdb from DB13?

[thorsten_zielke · Accepted solution]

Hi,

selectivity is the relationship of how many data rows have to be read in order to get the result set. In your example, MaxDB needs to process 1.179.127.082 rows just to deliver 69.556 rows to the application.

I would suggest activating the Command Monitor or the Resource Monitor or look into the 'running_commands' from the Database Analyzer to try to get to the SQL statement for possible optimization. Please have a look at note 819324 for further information.

Thorsten