Search

Top 60 Oracle Blogs

Recent comments

Home

aws

DynamoDB: adding a Local covering index to reduce the cost

Submitted by Franck Pachot on Mon, 2020-03-16 16:28

By Franck Pachot

.
This is a continuation on the previous post on DynamoDB: adding a Global Covering Index to reduce the cost. I have a DynamoDB partitioned on “MyKeyPart”,”MyKeySort” and I have many queries that retrieve a small “MyIndo001” attribute. And less frequent ones needing the large “MyData001” attribute. I have created a Global Secondary Index (GSI) that covers the same key and this small attribute. Now, because the index is prefixed by the partition key, I can create a Local Secondary Index (LSI) to do the same. But there are many limitations. The first one is that I cannot add a local index afterwards. I need to define it at the table creation.

Drop table

Here I am in a lab so that I can drop and re-create the table. In real live you may have to create a new one, copy the items, synchronize it (DynamoDB Stream),…

DynamoDB: adding a Global covering index to reduce the cost

Submitted by Franck Pachot on Mon, 2020-03-16 15:57

By Franck Pachot

.
People often think of indexes as a way to optimize row filtering (“get item” faster and cheaper). But indexes are also about columns (“attribute projection”) like some kind of vertical partitioning. In relational (“SQL”) databases we often add more columns to the indexed key. This is called “covering” or “including” indexes, to avoid reading the whole row. The same is true in NoSQL. I’ll show in this post how, even when an index is not required to filter the items, because the primary key partitioning is sufficient, we may have to create a secondary index to reduce the cost of partial access to the item. Here is an example with AWS DynamoDB where the cost depends on I/O throughput.

Oracle and the Future

Submitted by dbakevlar on Mon, 2020-01-06 20:25

We’ll start with a disclaimer here- this is my experience and my opinion. NO ONE ELSE’S, just as any link to any blog in this post is. Take it or leave it, I really don’t care, never have, never will- never been one to follow any drummer but my own anyway. </p /> </em></strong></p></div> <div class=

Importing geo-partitioned data… the easy way

Submitted by glennfawcett on Sat, 2019-12-07 02:16

 

setting the stage

I started at Cockroach labs back in June 2019 to help others learn how to architect and develop applications using a geo-distributed database.  There has been a resurgence in distributed database technology, but the focus on geo-distributed is quite unique to CockroachDB.  While the underlying technology is unique, developers and DBAs that come with a wealth of experience, need to know how to best use this innovative technology.  Given this situation, I thought it would be good to start a blog series to explore various topics facing anyone beginning to architect database solutions with CockroachDB.

To start using a database, the first step is to IMPORT table data so you can begin to see how the database performs and responds.  And thus the IMPORT series has started!

#Exasol on #AWS: Elasticity with #Cloud UI

Submitted by Uwe Hesse on Fri, 2019-12-06 09:41

This is the second part of the mini-series Exasol on AWS. Here’s the first part.

Cloud UI is an extension to EXAoperation that makes it easy for you to

  • Scale up & down
  • Increase storage capacity
  • Scale out by adding nodes to the cluster

Cloud UI can be reached by adding the port number 8835 to the URL of your License Server and uses the same credentials as EXAoperation.

Scale down to m5.large with Cloud UI

Depending on the load you get on your Exasol cluster, you can scale up your data nodes to more powerful EC2 instances if load is high and scale down to less expensive EC2 instances with lower user demands.

I started my little cluster with r5.large instances. Now I want to scale down to m5.large. Enter Cloud UI:

Getting started with #Exasol on #AWS

Submitted by Uwe Hesse on Wed, 2019-11-13 15:50

It’s amazingly easy to run an Exasol Cluster on Amazon Web Services (AWS).

Subscribe Exasol in AWS marketplace

After having registered and having logged in to your AWS account, go to the AWS marketplace and search for Exasol:

RMOUG Training Days 2018

Submitted by dbakevlar on Tue, 2018-02-06 22:33

So Training Days is coming up in two weeks.  You haven’t registered to attend?  How you feeling about that?

Rocky Mountain Oracle User Group, (RMOUG) has the largest Oracle user group grassroots conference each February.  For the 2018 year, we decided to shake it up with:

Spectre and Meltdown, Oracle Database, AWS, SLOB

Submitted by Franck Pachot on Tue, 2018-01-09 22:23

Last year, I measured the CPU performance for an Oracle Database on several types of AWS instances. Just by curiosity, I’ve run the same test (SLOB cached reads) now that Amazon has applied all Spectre and Meltdown mitigation patches.

I must admit that I wanted to test this on the Oracle Cloud first. I’ve updated a IaaS instance to the latest kernel but the Oracle Unbreakable Enterprise Kernel does not include the Meltdown fix yet, and booting on the Red Hat Compatible Kernel quickly goes to a kernel panic not finding the root LVM.

Upgrading an Amazon EC2 Delphix Target, Part IV

Submitted by dbakevlar on Mon, 2017-08-07 14:44

It’s finally time to upgrade our Linux Target!  OK, so we’re not going to upgrade the way a DBA would normally upgrade a database server when we’re working with virtualization.

So far, we’ve completed:

  • 1.  Updating our instances so that we’ll have a GUI interface if we’ll need one.
  • 2.  Installed Oracle on the Linux Source and upgraded our Dsource database to 12c

 

Now we’re done with our Linux Source and onto our Linux Target.

Upgrading an Amazon EC2 Delphix Source, Part III

Submitted by dbakevlar on Mon, 2017-07-31 19:40

This is the Part III in a four part series on how to:

  1.  Enable VNC Viewer access on Amazon EC2 hosts.
  2.  Install DB12c and upgrade a Dsource for Delphix from 11g to 12c, (12.1)
  3.  Update the Delphix Configuration to point to the newly upgraded 12c database and the new Oracle 12c home.
  4.  Install DB12c and upgrade target VDBs for Delphix residing on AWS to 12.1 from the newly upgraded source.

In Part II, we finished upgrading the Dsource database, but now we need to get it configured on the Delphix side.