ORA-1555 won’t get reported into alert.log anymore since 19.4.0

Many thanks to a German customer for showing me this tiny behavior change with Oracle Database RU 19.4.0. From this RU on the well known ORA-1555 won’t get reported into alert.log anymore since 19.4.0. But if you still like to see the “snapshot too old” error, then you can use a workaround.

Why has this been changed?

Actually this is something I don’t understand completely. It may be just a side effect. Unpublished fix bug 29424999 – DUMP MINIMAL DIAGNOSTICS BY DEFAULT IN CASE OF ORA-01555 IN ADW/ATP ENV has been

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AutoUpgrade and the Partial Offline Backup Strategy

In our Fallback talk we promote a backup strategy for large DWHs and database which are on purpose in NOARCHIVELOG mode. But last week I learned that there is something important to know about AutoUpgrade and the Partial Offline Backup Strategy. Otherwise you may hit a

AutoUpgrade and the Partial Offline Backup Strategy

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Partial Offline Backup Strategy?

I won’t explain in all details what this is. If you’d like to read more, please find all the necessary information on my blog post from July 17, 2018:

with graphics included. In brief, you take …

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AutoUpgrade may fail when patch ID column is NULL

Monday morning – it’s time to write a new blog post. And actually I will set priorities based on what you reported to me in the past week. This way it may prevent others from hitting the same pitfall. The AutoUpgrade may fail when patch ID column is NULL in REGISTRY$HISTORY.

AutoUpgrade may fail when patch ID column is NULL

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What is happening?

You start a database upgrade with autoupgrade. But the initial check will fail with a message like this:

AutoUpgrade tool launched with default options
There was an error initializing the patching information for entry upg2

The AutoUpgrade won’t kick …

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RMAN Catalog Upgrade fails – ORA-02296 – error creating modify_ts_pdbinc_key_not_null

This issue got raised to my via a customer I know for quite a while – all credits go to Andy Kielhorn for digging down into that issue and solving it.

Failed RMAN Catalog Upgrade from to

The RMAN catalog upgrade:

SQL> @?/rdbms/admin/dbmsrmansys.sql

$ rman CATALOG rman/xxx@rman01



failed with the following sequence of error messages:

error creating modify_ts_pdbinc_key_not_null
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-06004: ORACLE error from recovery catalog database: ORA-02296: cannot enable (RMAN.) - null values found

error creating modify_tsatt_pdbinc_key_not_null
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR 
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GC Freelist Session Waits causing slowness and hangs

Best Practice Hint

One of the best things in my job:
I learn from you folks out there. Everyday.

Credits here go to Maciej Tokar who did explain the below topic to me via LinkedIn – thanks a lot, Maciej!

Locks are not being closed fast enough, resulting in gc freelist waits

You can find a reference for Global Cache Freelist in the Oracle Documentation. This issue here can or will lead to database being slow, up to complete hangs. Based on my research it looks as the issue is not related to RAC only but a general thing. In your session …

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Parameter Recommendations for Oracle Database 12c – Part II

Best Practice Hint
See also:

Time for a new round on Parameter Recommendations for Oracle Database 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. And even if you still work on Oracle Database 11g some of the below recommendations may apply to your environment as well.


Again, please be advised – the following parameter list is mostly based on personal experience only. Some of them are officially recommended by Oracle

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