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Database Feed

Oracle Database, Oracle 10g, Oracle 11g, Oracle XE, Oracle RAC, Oracle Instant Client, Oracle Data Guard and Oracle Exadata resources, news, and support articles.

12c Downgrade

No, not really – but sometimes the optimizer gets better and gives you worse performance as a side effect when you upgrade. Here’s an example where recognised (with a few hints) the case for a nested loop semi-join and 12c went a bit further and recognised the opportunity for doing a cunning “semi_to_inner” transformation … which just happened to do more work than the 11g plan.

Around the world flight 6 – from Lisbon to Faro

A spectacular flight down the coast of Portugal leads our journey to Faro in the Faro District of the Algarve region, in southern Portugal. Faro is famous for it’s 200 km golden coastline and the lagoons. Its 30,000-seat stadium Estádio Algarve, shared by the cities of Faro and Loulé, was one of the venues of the […]
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Putting Data Guard traffic on dedicated network interface

I recently had an interesting challenge to direct data guard network traffic over a dedicated network interface and not go though the main network routes. The reason was that in order to reach the remote datacenter, the dataguard traffic should be sent via WAN optimizer network, that will automatically compress and dedup all traffic (hard to believe, that there are still some places left in Europe, where internet bandwidth is extremely expensive).

RMAN -- 5b : (More) Useful KEYWORDs and SubClauses

Here are a few more useful KEYWORDs and SubClauses

SECTION SIZE allows you to split a single Database file into multiple sections.  Note : A Database File  span BackupPieces.  The difference between BackupPieces and Sections is that the former are serially done while Sections can be done in-parallel.  (SECTION SIZE cannot be used with MAXPIECESIZE).  Here, I first show a datafile in 4 BackupPieces defined by SECTION SIZE.

SQL> select file_id, size_mb
2 from

Focusing on Ext4 and XFS TRIM Operations – Part I.

I’ve been doing some testing that requires rather large file systems. I have an EMC XtremIO Dual X-Brick array from which I provision a 10 terabyte volume. Volumes in XtremIO are always thinly provisioned. The testing I’m doing required me to scrutinize default Linux mkfs(8) behavior for both Ext4 and XFS. This is part 1 in a short series and it is about Ext4.

OCM 11g Preparation – Configure baseline templates

There are three types of baselines: Fixed, Moving Windows and Templates. In this chapter, we will focus in the third one, where our target is to create baselines for a contiguous time period in the future. There are two types of baseline templates: single and repeating.
They are very easy to create through “DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE_TEMPLATE” procedure. In the documentation, in less than 10 seconds you can reach that procedure with examples for both cases.

sorting algorithm

I have to share this Picture which is really amazing and include all the sorting algorithm in one picture 

Log Buffer #432: A Carnival of the Vanities for DBAs

Yet again, this log buffer edition brings some rich blog posts from Oracle, SQL Server and MySQL.


Real Life DBA: Finding Errors in SQL Server

I tend to spend time on a few different forums at times, mostly the StackExchange network, and find folks asking questions about various errors seen in the error log of an SQL Server instance. Most DBAs are aware that errors that SQL Server provides can be vague at times, so it takes a bit of knowing where to look for more information. In some situations it is after the fact before you can get to the instance to start your analysis so you have to focus on those areas that contain historical information. A few of those places to check are:

Announcing “SLOB Recipes”

I’ve started updating the SLOB Resources page with links to “recipes” for certain SLOB testing. The first installment is the recipe for loading 8TB scale SLOB 2.3 Multiple Schema Model with a 2-Socket Linux host attached to EMC XtremIO. Recipes will include (at a minimum) the relevant SLOB program output (e.g., or, init.ora and slob.conf.

Please keep an eye on the SLOB Resources page for updates…and don’t miss the first installment. It’s quite interesting.

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