AWR

Lost AWR snapshots reappear again in Oracle 12.2 in Multitenant

Lost AWR snapshots reappear again in Oracle 12.2 in MultitenantWhat a strange topic. And I thought I never will blog about this. But as I have received the same question for the third time today, I think there’s a bit clarification needed. Lost AWR snapshots reappear in Oracle 12.2 in Multitenant pluggable databases.

Magically …

Lost AWR snapshots reappear again in Oracle 12.2 in Multitenant

In a non-CDB database you have your local AWR data stored in the SYSAUX tablespace. Whenever you create an AWR snapshot:

exec dbms_workload_repository.create_snapshot;

You can query and of course evaluate it afterwards:

select con_id, snap_id, snap_level, to_char(begin_interval_time, 'dd/mm/yy hh24:mi:ss') BEGIN
from CDB_HIST_SNAPSHOT order by 
[ Read more ]

Gather SQL Statements from AWR and Cursor Cache without need for Diag and Tuning Packs

When we talk about database upgrades and migrations the most important (and unfortunately time-/resource consuming) activity is testing.

But often testing resources are limited or, even worse, don’t exist. I’ve worked with customers where we migrated a core EBS system off AIX to Linux – but only got a 6 year old Tru64 box for testing purposes (where the recompilation took 20x as long as later on the production environment). Or the classic one: Database is too big thus we test only with 10% of the data.

I know that often your hands are tied. Everybody wants an 1:1 … [ Read more ]

How to select statements from AWR?

Simple question – and more a reminder to myself as I’d assume that many people have their examples somewhere already. But in upgrade and migration projects it’s sometime useful to simply select SQL statements directly from between two AWR snapshots into a SQL Tuning Set (STS). This will give you the possibility to later put a failing plan directly into a SQL Plan Baseline, part of the free Enterprise Edition’s SQL Plan Management feature.

Please find a scripted example for download here:

You’ll need to create a SQL Tuning Set and simply fill it with staments from an AWR … [ Read more ]