dbms_diskgroup read very slow on exa
Date: Tue, 23 Mar 2021 13:22:27 +0200
Message-ID: <CA+riqSUxMjLj1_+YKZTnohDZ2uXEusAmE5r9OHHFayEhq7GAXA_at_mail.gmail.com>
Hello all,
I received complaints about Attunity doing the ingestion very slowly. The way is configured is to connect directly to ASM instance and get the archivelog files.This is an exa X7
My observations wre:
-> is using dbms_diskgroup.read to perform the reads from asm
-> mainly the wait time is ASM Fixes Package I/O (and some CPU)
-> Is using 16 sessions distributed over 2 nodes each reading with an
estimate speed (based on ASH numbers) of around 10MBPS
-> in case a smart scan starts (for example smart incremental backup) the
I/O speed of these sessions drops to around 1MBPS
-> session level stats shows a very low number for "cell flash cache read
hits" so looks like all reads are from spinning disks
To me it looks like the reading speed even in normal conditions(without heavy competition) is very low, can someone help me with some hints on what can be the culprit?
Thank you.
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Mar 23 2021 - 12:22:27 CET