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OCM 12c preparation: Create CDB in command line
This post starts a series about things I wrote while preparing the OCM 12c upgrade exam. Everything in those posts are written before taking the exam – so don’t expect any clue about the exam here....
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OCM 12c preparation: Manage PDB
Let’s see the different ways to create a PDB, with different tools. Same disclaimer here as in the first post of the series: don’t expect to get those posts close to what you will have at the exam, but...
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SQL Plan Directive: disabling usage and column groups
Yesterday I came upon a comment on oracle-l while I was reading my slides for the UKOUG TECH15 SuperSunday. I’ve one slide and one demo about disabling SPD usage but that’s not enough to explain all...
View ArticleOCM 12c preparation: Transportable Tablespaces
I use transportable tablespaces a lot since 8i, here are just a few examples. Same disclaimer here as in the first post of the series: don’t expect to get those posts close to what you will have at the...
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OCM 12c preparation: Explain fast refresh
There are some rules to be able to fast refresh a materialized view (which means, refresh it so that it is not stale, and without running the whole query). Documentation is in the Datawarehouse Guide,...
View ArticleOCM 12c preparation: documentation
The OCM exam advice says: Be prepared to use the non-searchable documentation during the exam, to help you with correct syntax. I’ve checked that I can find quickly the documentation related with each...
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OCM 12c preparation: Data Guard with OEM
I never create a Data Guard configuration from Enterprise Manager. It’s not that I don’t like GUI, but it is a lot easier to document it when doing from command line: copy paste the commands (actually...
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OCM 12c preparation: RAT in multitenant
I have several customers that have cases where Real Application Testing can be interesting, but they don’t use it because it’s an expensive option. Which is why it’s probably the topic listed for OCM...
View ArticleOCM 12c preparation: restore Voting disks, OCR and ASM spfile
As in the previous posts, here are a few commands I used to check that I know how to restore the cluster mandatory files in 12c. It’s what I’m doing while preparing the OCM 12c exam, but without any...
View ArticlePhantom session environment in multitenant?
In multitenant a session can switch from one container to another. There are a few restrictions such as a transaction cannot span multiple containers. But how do sessions parameters behave? It seems...
View ArticlePDB snapshot copy for continuous integration testing
How do you manage your continuous integration tests on the database? You need to restart at the same state for probably a hundred of tests. Recreating the schema and test data takes too long. Oracle is...
View ArticlePDB Snapshot using dbms_dnfs.clonedb_renamefile
In the previous post I’ve explained how to use ‘snapshot copy’ PDB creation for thin provisioning and quick restore of initial state for continuous integration tests. If you don’t have the multitenant...
View ArticleFlashback table after multiple drop
FLASHBACK TABLE restores the latest version that is available in recycle bin. If you did multiple drop / create you may want to restore oldest versions. Of course it’s documented – everything is in the...
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log file sync / user commits
When presenting ‘Interpreting AWR Reports – Straight to the Goal’ at UKOUG TECH15 I had a very good question about the Statspack report I read which had log file sync much smaller than user commits. I...
View ArticleDataPump ‘Processing object type’ misleading messages
You’ve started a long DataPump and see it stuck on TABLE/STATISTICS/TABLE_STATISTICS, but you don’t expect that step to take a long time. Let’s see if we can rely on that message. I’ve a 500MB table...
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Execution Plan with ASH
Here is a query I use when I’m on a system that has Diagnostic Pack (ASH) but no tuning Pack (SQL Monitor). It displays the execution plan with dbms_xplan.display_cursor and adds the % of ASH samples...
View ArticleOFE – Optimizer Features Enable
Do you know the optimizer_features_enable parameter? What do you think about it? Good or bad to user it? If I tell you to set optimizer_features_enable parameter=11.2.0.4 when you upgrade to 12c, do...
View Articleawrrpt and spreport in multitenant
Yesterday I was giving my ‘Interpreting AWR Reports’ Prezi at Oracle Midlands. There is a point where I explain that I always check the ‘Captured SQL account for …% of Total DB Time (s)’ in order to...
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SQL Plan Directives strike again
12c SQL Plan Directives, a side effect, a bad application design, a bug… and the occasion to show how to quickly troubleshoot. An application has long response time since 12c migration. No blind...
View Article12c online datafile move and ongoing changes
Here is a long answer for a question on our forum about online move: what is internal mechanism to store/keep ongoing changes in that particular datafile while copying is in progress. The short answer...
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