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September 2017

Wrong result with multitenant, dba_contraints and current_schema

Multitenant architecture is not such a big change and this is why I recommend it when you start a project in 12c or if you upgrade to 12.2 – of course after thoroughly testing your application. However, there is a point where you may encounter problems on dictionary queries, because it is really a big change internally. The dictionary separation has several side effects. You should test carefully the queries you do on the dictionary views to get metadata. Here is an example of a bug I recently encountered.

This happened with a combination of things you should not do very often, and not in a critical use case: query dictionary for constraints owned by your current schema, when different than the user you connect with.

AskTOM TV–episode 11

Just a quick note to give the supporting collateral to the latest episode of AskTOM TV.

The question I tackled is this one:

https://asktom.oracle.com/pls/apex/asktom.search?tag=want-to-retrive-numbers-in-words

which was a fun one to answer because it showcases several useful SQL techniques:

Woo hoo … more OpenWorld 17 content

You bewdy! I managed to score myself a couple more mini-sessions at OpenWorld.

These will be in The Exchange, the re-designed venue for vendors and demonstrations at OpenWorld.

Come along as say Hi. It will be a whirlwind 20 minutes as I try cram as much information into the short time frame as I can.

See you there!

 

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Interview with PeopleSoft Administrator Podcast: Oracle Resource Manager

This week's  PeopleSoft Administrator Podcast includes a few minutes of me talking to Dan and Kyle about Oracle Resource Manager.

OpenWorld 2017–where is the tech content ?

I can’t actually remember how many OpenWorld conferences I have attended. At a guess it would be around 7 or 8. Every year there is a criticism that there is “not enough technical content”.

Data Gravity and the Network

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The network has often been viewed as “no man’s land” for the DBA-  Our tools may identify network latency, but rarely does it go into any details, designating the network outside our jurisdiction.

Partition-wise join

So just what is a “partition-wise” join ?  We will use a metaphor to hopefully Smile explain the benefit.

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Where in the World is Goth Geek Girl, Week #38

As we come upon Oracle Open World at the end of the month, I’m busy with a number of events and tasks.

I spoke at the Microservices, Containers and DevOps Summit in Denver yesterday and will be traveling to San Diego, California to speak at SQL Saturday #661 this weekend.  I love the Microsoft events, but not sure my family loves the loss of my weekend time with them half as much.

rollback internals

While researching redo log internals for V00D00 we had to face the fact, that we know shit about real transactional behavior. When I say "real", I mean – under the hood.
Even with a very simple stuff like COMMIT and ROLLBACK we were constantly amazed by the internal mechanisms.

Today let’s take ROLLBACK under the investigation. According to documentation:

The ROLLBACK statement ends the current transaction and undoes any changes made during that transaction.

Cool. But what it means? First of all, you have to realize that all changes in redo logs are in a form of REDO RECORD which has its own address, known as RBA or RS_ID.

Sample RS_ID (RBA) looks like this: 0x00000a.00008c0f.006c

rollback internals

While researching redo log internals for V00D00 we had to face the fact, that we know shit about real transactional behavior. When I say "real", I mean – under the hood.
Even with a very simple stuff like COMMIT and ROLLBACK we were constantly amazed by the internal mechanisms.

Today let’s take ROLLBACK under the investigation. According to documentation:

The ROLLBACK statement ends the current transaction and undoes any changes made during that transaction.

Cool. But what it means? First of all, you have to realize that all changes in redo logs are in a form of REDO RECORD which has its own address, known as RBA or RS_ID.

Sample RS_ID (RBA) looks like this: 0x00000a.00008c0f.006c