Tag: performance

Slimming Down Oracle RAC 12c’s Resource Footprint

Oracle Grid Infrastructure 12c uses a considerable amount of RAM and CPU resources; here are a few tips to shoehorn it into a 2GB virtual machine.

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High System Time on Windows Running in a VM

Recently I’ve seen an issue with CPU usage on a server running Windows 2003 Server in a VMware. This is a small Virtual Machine with just 2 cores allocated (which are possibly mapped to “threads” on a host level but…

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In-Memory Column Store: 10046 May Be Lying to You!

The Oracle In-Memory Column Store (IMC) is a new database option available to Oracle Database Enterprise Edition (EE) customers. It introduces a new memory area housed in your SGA, which makes use of the new compression functionality brought by the…

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Comparing CPU Throughput of Azure and AWS EC2

After observing CPU core sharing with Amazon Web Services EC2, I thought it would be interesting to see if Microsoft Azure platform exhibits the same behavior. Signing up for Azure’s 30-day trial gives $200 in credit to use over the…

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vCPU sharing in EC2: HVM to the rescue?

I’ve been doing some testing to clarify what a vCPU in Amazon Web Services actually is. Over the course of the testing, I experienced inconsistent results on a 2-thread test on a 4-vCPU m3.xlarge system, due to the mislabeling of…

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Virtual CPUs with Amazon Web Services

The definition of a vCPU in Amazon Web Services is a bit unclear. We run some tests to see how much CPU performance we actually get, and discover some unexpected side effects from AWS’s implementation.

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SQL Server Statistics: Maintenance and Best Practices

What are Statistics? There are multiple paths a database can use to answer a query, some of them being faster and more efficient than others. It is the job of the query optimizer to evaluate and choose the best path,…

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Do AWR Reports Show the Whole Picture?

AWR report is a great source of aggregated information on top activities happening in our databases. I use data collected in AWR quite often, and obviously the easiest way of getting the data out from the AWR is by running the…

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Do you have enough Redo?

The question of whether a database has enough redo logs available is quite common. The documentation suggests to use FAST_START_MTTR_TARGET and V$INSTANCE_RECOVERY.OPTIMAL_LOGFILE_SIZE to identify “the optimal” redo log size based on the target recovery time. I’ve never used it and…

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Batched Table Access

When I first saw the suffix BATCHED in an Oracle execution plan from 12c, I was curious to see what is hidden behind and how it works. I had some spare time for testing and wanted to share my findings…

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