System calibration

From: Mladen Gogala <>
Date: Fri, 17 May 2019 07:20:12 -0400
Message-ID: <>

Oracle 19c has parameters MAX_IOPS and MAX_MBPS which set the values that used to be set by using dbms_resource_manager.calibrate_io procedure. Does that mean that we can now use SLOB or bonnie++ to determine the IO system performance instead of running the notoriously unreliable calibrate_io? From the documentation, I got the impression that this is sort of a hard limit:

On the other hand, calibrate_io was previously used only for determining the automatic degree of parallelism and wasn't set as a hard limit. The new mechanism will make the processes wait should the IO rate exceeds the one defined by parameters. Will the optimizer use this or SYS.RESOURCE_IO_CALIBRATE$ to determine the automatic degree of parallelism, where that is enabled? We can have one value in the parameters and something completely different in SYS.RESOURCE_IO_CALIBRATE$.

Mladen Gogala
Database Consultant
Tel: (347) 321-1217

-- Received on Fri May 17 2019 - 13:20:12 CEST

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