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Renaming an Oracle Apache Target in EM12c

When installing Enterprise Manager 12c, the host value can come from a number of places for different applications/tiers.  For most, it comes from the environment variable $ORACLE_HOSTNAME, (for Windows Servers, %ORACLE_HOSTNAME%).

Dealing with Wi-Fi Problems the DBA Kevlar Way

As much as KSCOPE 14 fixed any and all Low-T levels, it couldn’t do anything for our the WiFi problems we were experiencing back in May. I’ve been a telecommuter for almost 4 straight years now and was quite frustrated when our WiFi service became dismal back then.

ALS Ice Bucket Challenge : Keeping It In The Family

If you watched my (No) Ice Bucket Challenge yesterday, you will know I nominated my Oracle family.

The first family member to step up to the plate was the daughter, Heli “Hell-Squirrel” Helskyaho. She shared the video on Facebook, which you can see here if you are a friend. We have to be careful with the parental controls to keep her safe!

Next up was the wife, Debra Lilley, who used the opportunity to do an Oscar acceptance speech.

In-memory Aggregation

The title of this piece is the name given to a new feature in 12.1.0.2, and since I’ve recently blogged about a limitation of the in-memory option I thought I’d pick this feature as the next obvious thing to blog about. This is a bit of a non sequitur, though, as the feature seems to have nothing whatsoever to do with the in-memory option; instead it’s a cunning mechanism combining aspects of the star-transformation (but without the bitmap indexes), Bloom filters, and “group-by” placement to minimise the cost of aggregation over high-volume joins.

Here’s a small data set I’ll use to demonstrate the feature:

SLOB Physical I/O Randomness. How Random Is Random? Random!

I recently read a blog post by Kyle Hailey regarding some lack of randomness he detected in the Orion I/O generator tool. Feel free to read Kyle’s post but in short he used dtrace to detect Orion was obliterating a very dense subset of the 96GB file Orion was accessing.

ALS (No) Ice Bucket Challenge

Ronald Vargas challenged me to the ALS Ice Bucket Challenge. Unfortunately we didn’t have any ice, but the water was cold anyway, as you can see by my reaction at the end. :)

I challenge Debra Lilley, Graham Wood and Heli Helskyaho.

Please don’t forget to donate!

Cheers

Tim…

Quiz night

Here’s a script to create a table, with index, and collect stats on it. Once I’ve collected stats I’ve checked the execution plan to discover that a hint has been ignored (for a well-known reason):

Multitenant : PDB CONTAINERS Clause

I forgot to mention, I put another multitenant article live at the weekend.

I’m not sure I will ever use it, but it’s good to know it’s there.

I was originally working on an article on a completely different multitenant feature, but the examples I was using highlighted a bug, which kind-of scuppered that article. I’ve raised an SR and I’m waiting on the acknowledgement and possible fix. I’ll hold that article back until the fix is in place.

Cheers

Tim…

LOB Length

It’s funny how you can make little savings in work all over the place in Oracle if you’re prepared to look a little closely at what’s going on. Here’s a quirky little example with LOBs and function calls that might just have some greater relevance in other situations. Here’s a little data set, and two queries that I might run against it:

Weblogic Start Failure: Empty Initial Replica

This post is to address a failed Weblogic start in EM12c.  The fix is performed on a Windows host, but the fix can easily be for any EM12c environment that experiences this issue.  In the below instructions, just replace the %OMS_BASE% for Windows Env Var to $OMS_BASE for Linux/Unix.

Issue:  OMS Fails to Start and Points to Weblogic Issue in EMGC_OMS1.out File.