John Watson's blog

Installing database 19c on Oracle Linux 8

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Database release 19.7 (ie, 19c with the April 2020 RU) is at last certified for OL8, but there may be some hacking needed to get it installed.

This certification is long overdue: our security admin has been pushing for the 5.x kernel for some time, and OL7 still only supports kernel 4.x. I'm starting to move some production systems over now using the July RUR, which takes the release to 19.7.1.

Begin by installing the Oracle Validated rpm from the ol8_UEKR6 repository:

yum install oracle-database-preinstall-19c

Controlling distributed queries with hints

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Recently I've been working on tuning some distributed queries. This is not always straightforward.

Database 20c docs

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Now available!
https://docs.oracle.com/en/database/oracle/oracle-database/20/books.html

Going through the New Features guide, there is a shed load of wonderful enhancements. Then you look at the Licensing guide, and most of them require Exadata or Oracle Cloud or both.

How to move a table from one schema to another

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Many times I've seen the question on forums "How can I move a table from one schema to another?" and the answer is always that you can't. You have to copy it. Or export/import it. Well, here's a way. It assumes that you are on release 12.x and have the partitioning option.

Oracle now supported on VMware

Oracle corporation will (as of 24 September 2019) support customers running on VMware.

19c Standard Edition permits 3 PDBs per CDB

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A very nice licensing change in 19c: you can now have up to three PDBs in a Standard Edition Multitenant database.

12.2 upgrade - it can break all your outgoing https calls

Do you know about multiple domain certificates? If not you may have to learn quickly, because Oracle has changed the way they are handled in release 12.2. This is going to break a lot of applications.

Upgrading to 12.2 ? Make sure you won't break JSON

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Will upgrade from 12.1 to 12.2 break your applications? It may if your developers are using JSON.

Tuning with equivalent SQLs - a little challenge

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I am fascinated by what I call "equal SQL": statements that are equivalent, in that they deliver the same result but may have hugely different performance characteristics. Here's a little case study.

Compression test, 12cR2

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Just how effective is Hybrid Columnar Compression? This test shows that HCC is impressive, but that thought needs to be put into choice of compression algorithm.

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