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Hot cloning and refreshing PDBs in #Oracle 12cR2

Hot cloning PDBs is new in 12.2, so you don’t have to put the source PDB into READ ONLY mode before the cloning if you have it in local undo mode. I suppose shared undo mode will become very unpopular. Another 12.2 New Feature is the option to clone a PDB that can be refreshed from the source PDB. I will show both features with this article, but you may of course do hot cloning without a later refresh. In this case, just leave out the REFRESH MANUAL clause and you don’t have to OPEN READ ONLY the cloned PDB afterwards. On a high level, what I demonstrate is this:

Happy New YouTube Channel!

As announced, I start into 2017 with my own YouTube channel. You can access it at the right upper part of this site by clicking on the red icon:

Happy New Year 2017!

fireworks-animation

How to upgrade a Pluggable Database to 12cR2 in #Oracle

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How to configure FLASHBACK in #Oracle

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New mean demo machine

My new Notebook is there! Will spend a couple of hours to do the setup. The specs are quite promising:

CPU:
Intel Core i7-6700 | 4 Cores | 8 Threads | 3,4 – 4,0GHz
Memory:
32GB  SO-DIMM DDR4 RAM 2400MHz Crucial Ballistix Sport LT
6 TB SSD Storage:
1TB m.2 Crucial MX300
1TB m.2 Crucial MX300
2TB Seagate FireCuda | 5400U/Min | 7mm
2TB Seagate FireCuda | 5400U/Min | 7mm

Okay it did cost me a fortune. See the new one on the left:

nc

#ukoug_tech16 Review with Tweets

UKOUG Tech16 is in its final hours, time for a special review: Tweets about it

It was in Birmingham again – very nice location!

 

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Standard Edition attracts not only my attention more and more

How to reduce Buffer Busy Waits with Hash Partitioned Tables in #Oracle

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Large OLTP sites may suffer from Buffer Busy Waits. Hash Partitioning is one way to reduce it on both, Indexes and Tables. My last post demonstrated that for Indexes, now let’s see how it looks like with Tables. Initially there is a normal table that is not yet hash partitioned. If many sessions do insert now simultaneously, the problem shows:

How to reduce Buffer Busy Waits with Hash Partitioned Indexes in #Oracle

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Buffer Busy Waits can be a serious problem for large OLTP systems on both tables and indexes. If e.g. many inserts from multiple sessions occur simultaneously, they may have to compete about the same index leaf blocks like the picture below shows:

How Partial Indexing helps you save space in #Oracle 12c

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Over time certain partitions may become less popular. In 12c, you don’t have to index these partitions anymore! This can save huge amounts of space and is one of the best 12c New Features in my opinion. Really a big deal if you are working with range partitioned tables where the phenomenon of old ranges becoming unpopular is very common. Let’s have a look, first at the problem: