Process home monitoring data using the Time Series Database in Bluemix

I keep a lot of information about my house – I have had sensors and recording units in various parts of my house years, recording info through a variety of different devices.

Over the years I’ve built a number of different solutions for storing and displaying the information, and when the opportunity came up to write about a database built specifically for recording this information I jumped at the change, and this is what I came up with:

As home automation increases, so does the number of sensors recording statistics and information needed to feed that data. Using the Time Series Database in BlueMix makes it easy to record the time-logged data and query and report on it. In this tutorial, we’ll examine how to create, store, and, ultimately, report on information by using the Time Series Database. We’ll also use the database to correlate data points across multiple sensors to track the effectiveness of heating systems in a multi-zone house.

You can read the full article here

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Office 365 Activation Wont Accept Password

So today I signed up for Office 365, since it seemed to be the easiest way to get hold of Office; although I have a license and subscription, I also have more machines.

To say I was frustrated when I tried to activate Office 365 was an understatement. Each time I went through the process, it would reject the password saying there was a problem with my account.

I could login with my email and password online, but through the activation, no dice. Some internet searches, including with the ludicrously bad Windows support search didn’t elicit anything useful.

Then it hit me. Office 2011 for Mac through an Office 365 subscription probably doesn’t know about secondary authentication.

Sure enough, I created and application specific password, logged in with that, and yay, I now have a running Office 365 subscription.

If you are experiencing the same problem, using a application specific password might just help you out.

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Hadoop BoF Session at OSCON

I have a BoF session next week at OSCON next week:

Migrating Data from MySQL and Oracle into Hadoop

The session is at 7pm Tuesday night – look for rooms D135 and/or D137/138.

Correction: We are now in  E144 on Tuesday with the Hadoop get together first at 7pm, and the Data Migration to follow at 8pm.

I’m actually going to be joined by Gwen Shapira from Cloudera, who has a BoF session on Hadoop next door at the same time, along with Eric Herman from We’ll use the opportunity to talk all things Hadoop, but particularly the ingestion of data from MySQL and other databases into the Hadoop datastore.

As always, it’d be great to meet anybody interested in Hadoop at the BoF, please come along and introduce yourselves, and hopefully I’ll see you next week!

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Making Real-Time Analytics a Reality — TDWI -The Data Warehousing Institute

My article on how to make the real-time processing of information from traditional transactional stores into Hadoop a reality has been published over at TDWI:

Making Real-Time Analytics a Reality — TDWI -The Data Warehousing Institute.

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Replicating Oracle Webinar Question Follow-up

We had really great webinar on Replicating to/from Oracle earliest this month, and you can view the recording of that Webinar here.

A good sign of how great a Webinar was is the questions that come afterwards, and we didn’t get through them all. so here are all the questions and answers for the entire webinar.

Q: What is the overhead of Replicator on source database with asynchronous CDC?

A: With asynchronous operation there is no substantial CPU overhead (as with synchronous), but the amount of generated redo logs becomes bigger requiring more disk space and better log management to ensure that the space is used effectively.

Q: Do you support migration from Solaris/Oracle to Linux/Oracle?

A: The replication is not certified for use on Solaris, however, it is possible to configure a replicator to operate remotely and extract from a remote Oracle instance. This is achieved by installing Tungsten Replicator on Linux and then extracting from the remote Oracle instance.

Q: Are there issues in supporting tables without Primary Keys on Oracle to Oracle replication?

A: Non-primary key tables will work, but it is not recommended for production as it implies significant overhead when applying to a target database.

Q: On Oracle->Oracle replication, if there are triggers on source tables, how is this handled?

A: Tungsten Replicator does not automatically disable triggers. The best solution is to remove triggers on slaves, or rewrite triggers to identify whether a trigger is being executed on the master or slave and skip it accordingly, although this requires rewriting the triggers in question.

Q: How is your offering different/better than Oracle Streams replication?

A: We like to think of ourselves as GoldenGate without the price tag. The main difference is the way we extract the information from Oracle, otherwise, the products offer similar functionality. For Tungsten Replicator in particular, one advantage is the open and flexible nature, since Tungsten Replicator is open source, released under a GPL V2 license, and available at

Q: How is the integrity of the replica maintained/verified?

A: Replicator has built-in real-time consistency checks: if an UPDATE or DELETE doesn’t update any rows, Replicator will go OFFLINE:ERROR, as this indicates an inconsistent dataset.

Q: Can configuration file based passwords be specified using some form of encrypted value for security purposes to keep them out of the clear?

A: We support an INI file format so that you do not have to use the command-line installation process. There is currently no supported option for an encrypted version of these values, but the INI file can be secured so it is only readable by the Tungsten user.

Q: Our source DB is Oracle RAC with ~10 instances. Is coherency maintained in the replication from activity in the various instances?

A: We do not monitor the information that has been replicated; but CDC replicates row-based data, not statements, so typical sequence insertion issues that might occur with statement based replication should not apply.

Q: Is there any maintenance of Oracle sequence values between Oracle and replicas?

A: Sequence values are recorded into the row data as extracted by Tungsten Replicator. Because the inserted values, not the sequence itself, is replicated, there is no need to maintain sequences between hosts.

Q: How timely is the replication? Particularly for hot source tables receiving millions of rows per day?

A: CDC is based on extracting the data at an interval, but the interval can be configured. In practice, assuming there are regular inserts and updates on the Oracle side, the data is replicated in real-time. See for more information on how this figure can be tuned.

Q: Can parallel extractor instances be spread across servers rather than through threads on the same server (which would be constrained by network or HBA)?

A: Yes. We can install multiple replicators and tune the extraction of the parallel extractor accordingly. However, that selection would need to be manual, but certainly that is possible.

Q: Do you need the CSV file (to select individual tables with the configuration) on the master setup if you want all tables?

A: No.

Q: If you lose your slave down the road, do you need to re-provision from the initial SCN number or is there a way to start from a later point?

A: This is the reason for the THL Sequence Number introduced in the extractor. If you lose your slave, you can install a new slave and have it start at the transaction number where the failed slave stopped if you know it, since the information will be in the THL. If not, you can usually determine this by examining the THL directly. There should be no need to re-provision – just to restart from the transaction in the THL on the master.

Q: Regarding a failed slave, what if it failed such that we don’t have a backup or wanted to provision a second slave such that it had no initial data.

A: If you had no backups or data, yes, you would need to re-provision with the parallel extractor in order to seed the target database.

Q: Would you do that with the original SCN? If it had been a month or two, is there a way to start at a more recent SCN (e.g. you have to re-run the setupCDC process)?

A: The best case is to have two MySQL slaves and when one fails, you re-provision it from the healthy one. This avoids setupCDC stage.

However, the replication can always be started from a specific event (SCN) provided that SCN is available in the Oracle undo log space.

Q: How does Tungsten handle Oracle’s CLOB and BLOB data types

A: Providing you are using asynchronous CDC these types are supported; for synchronous CDC these types are not supported by Oracle.

Q: Can different schemas in Oracle be replicated at different times?

A: Each schema is extracted by a separate service in Replicator, so they are independent.

Q: What is the size limit for BLOB or CLOB column data types?

A: This depends on the CDC capabilities in Oracle, and is not limited within Tungsten Replicator. You may want to refer to the Oracle Docs for more information on CDC:

Q: With different versions of Oracle e.g. enterprise edition and standard edition one be considered heterogeneous environments?

A: Essentially yes, although the nomenclature is really only a categorization, it does not affect the operation, deployment or functionality of the replicator. All these features are part of the open source product.

Q: Can a 10g database (master) send the data to a 11g database (slave) for use in an upgrade?

A: Yes.

Q: Does the Oracle replicator require the Oracle database to be in archive mode?

A: Yes. This is a requirement for Oracle’s CDC implementation.

Q: How will be able to revisit this recorded webinar?

A: Slides and a recording from today’s webinar will be available at


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A New Home for Tungsten in the UK

I was suitably heartened to hear about the new mine opening up in the Devon here in the UK to mine the element Tungsten.

I comment on this to my associates at Continuent, where comments were made by Csaba as to the appropriate quotes in the article:

“Tungsten is an extraordinary metal.”

“It’s almost as hard as a diamond and has one of the highest melting points of any mineral.”

“Adding a small amount to steel makes it far harder, far more resistant to stress and heat. The benefits to industry are obvious.”

Leading to him to suggest Adding a small amount of Tungsten to MySQL makes it far harder, far more resistant to stress and failures. The benefits to industry are obvious.

I couldn’t possibly agree more!


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Continuent at Hadoop Summit

I’m pleased to say that Continuent will be at the Hadoop Summit in San Jose next week (3-5 June). Sadly I will not be attending as I’m taking an exam next week, but my colleagues Robert Hodges, Eero Teerikorpi and Petri Versunen will be there to answer any questions you have about Continuent products, and, of course, Hadoop replication support built into Tungsten Replicator 3.0.

If you are at the conference, please go along and say hi to the team. And, as always, if there are any questions please let them or me know.

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