Oracle 12.2 underscores appear in SPFILE – be aware when you flashback

Oracle 12.2 underscores appear in SPFILE - be aware when you flashbackI did blog in the past weeks about Fallback Strategies with Flashback Database. But two of my reference customers came across an interesting issue when they tried to fallback: Oracle 12.2 underscores appear in the SPFILE – magically – and prevent the fallback using the existing SPFILE.

Oracle 12.2 underscores appear in SPFILE – be aware when you flashback

In one case it happened during a test, in the other case it happened during a live fallback after the Data Guard Broker has interfered with the upgrade causing real trouble.… [Read More]

SGA_MIN_SIZE in Oracle Database 12.2

I did summarize all new init.ora/spfile parameters in Oracle Database 12.2.0.1 a while ago:

New SPFILE parameters in Oracle Database 12.2.0.1

And one caught Roy’s and my attention: SGA_MIN_SIZE.

When we present this new parameter as part of the Multitenant slides in our workshops, some people ask themselves:
“What happens if I oversubscribe such a parameter?” For example, if SGA_TARGET=4G and I have 10 PDBs and define in each of them SGA_MIN_SIZE=500M.… [Read More]

Parameter Recommendations for Oracle Database 12c – Part II

Best Practice Hint
See also:

Parameter Recommendations for Oracle Database 12c – Part I

Time for a new round on Parameter Recommendations for Oracle Database 12.1.0.2. The focus of this blog post settles on very well known parameters with interesting behavior. This can be a behavior change or simply something we’d like to point out.

[Read More]

Parameter Recommendations for Oracle Database 12c – Part I

Best Practice Hint

See also:

Parameter Recommendations for Oracle Database 12c – Part II


A few weeks ago we’ve published some parameter recommendations including several underscores but based on an internal discussion (still ongoing) we decided to remove this entry and split up the tasks. The optimizer team will take over parts of it and I’ll post an update as soon as something is published.… [Read More]

What happened to the blog post about “12c parameters”?

Best Practice Hint

Two weeks ago I published a blog post about Parameter Recommendations for Oracle Database 12.1.0.2. And I took it down a day later. Why that?

I’ve got a lot of input from external sources for the “Parameter” blog post. And I’d like to thank everybody who contributed to it, especially Oracle ACE Ludovico Caldara.[Read More]

New (some undocumented) Parameters in Oracle 12.1.0.2

Every release offers some surprises – even to myself šŸ˜‰

Right now Roy and I are in the final steps to refresh our big slide deck to the new layout, but more important, to have Oracle 12.1.0.2 information included as well (were necessary). So I did my usual “compare parameters” query between releases – getting unusual surprises this time.

[Read More]

Why you shouldn’t set OPTIMIZER_FEATURES_ENABLE

Roy today answered an interesting question on one of our internal mailing lists. And this reminds me to pick up that piece of information as we see this quite often on customer sites, especially after upgrades or migrations. People setĀ OPTIMIZER_FEATURES_ENABLEĀ (OFE) to revert the optimizer’s behaviour to another pre-current release.… [Read More]