Tag Archives: Commentary

Gilmerton Cove

I was fortunate enough recently to visit Gilmerton Cove. Despite the name, the cove is not located near the sea at all, but outside Edinburgh, and it is one of those places that makes you wonder how such a wonderful and intriguing location can have been kept as such a fantastic secret. We’ve visited Edinburgh lots of times and been to the castle, on the wonderful walks provided by Mercat tours and many other sites and locations. There is a lot of history and background to the city, all of it rich and colourful, and some of it surprising. I never knew, for example, about the extensive underground caves and crypts which use to fuel the lifeblood of the city producing matches, pins and more.

Gilmerton Cove though is different. It is located underneath a crossroads in Gilmerton and is a short bus ride from the centre of the city, it takes about 25 minutes from South Bridge (which sits above Waverley station). What you are looking for is the Gilmerton crossroads and Ladbrokes. Yes, you read that right. The cove is next, and more importantly, underneath, Ladbrokes.

Underneath gives you the main clue to what makes Gilmerton Cove such an interesting place. Entry is through a small door further down the road (you can just about see the sign from the crossroads), and once you get inside you are greeted by the wonderful staff. We were lucky to visit out of season and so there were only four of us, which gave the tour a little more of the personal touch, and our guide was the amazing Margaretanne.

The key about the cove is that it is really a cave, but it is man made. The mystery is that we don’t really know when or where. There are lots of clues beneath the ground of what it might have been, or what might have created it, but not enough information to provide a definitive answer.

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The first thing you notice about the cove is that the walls have quite clearly been worked, by person or more probably persons unknown. The area itself is quite large. Think generous 3-bedroom modern house and, in some ways, with a similar structure. There are individual rooms, some with quite clear doorways and entrances. There are also communal rooms and areas. One of these is quite clearly arranged as a sort of dining area, with a clear table up the middle of the room with seating either side.

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Note the careful modelling. This is not a convenient natural location; that table is too smooth and deliberate, and the proportions were perfect as a seating area. Also note in the top of the picture a gap which leads up, probably to allow either light in, smoke out, or both.

Another, larger, area is even more intriguing. Another seating area, with a carefully crafted pillar helping to support the ceiling. Not very visible in the foreground of this short is a hole, about the size of a large saucepan, quite obviously carved into the rock. The sides and base are smooth, and there’s even a lip around the edge. To me, it was very reminiscent of similar holes in the stonework in Pompeii which were used for keeping food hot or cold. You could easily seat 10 or 12 people here, and while you could hold a banquet, it would be convenient enough to hold a number of people for illicit drinks. And that, they believe, is one of the main uses for this in the past, as a drinking den.

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Further rooms, bedrooms?, lead off the main corridor. Some are large, some have dedicated fireplaces, and there are even alcoves and areas to display items. There’s even what appears to be a forge, although probably not a particularly efficient one. There are also a number of collapsed passageways, some of which lead in directions such as local churches, and even to just across the road. These are yet to be fully explored.

The only known information about Gilmerton Cove is that of George Paterson, a blacksmith, who supposedly created the ‘house’ after 5 years of hard labour in 1724. That’s a lot of house to have dug out by hand in just 5 years. For one man, even for a group of men, that is quite an achievement. With modern tools, yes, in 1724? There wasn’t a jackhammer, pneumatic drill, and the work is too precise to have been achieved with gunpowder, especially when you consider that even today, the shops above are feet and and inches above your head. This is not a deep construction – at one point you can actually reach up to touch the underneath of Ladbrokes next door.

There are carvings and initials around the caves – the sandstone is comparatively soft – but these could have been etched by people 5 years ago or 300 years ago, there’s no way to tell.

And the mystery remains. There are many theories, from the Hellfire Club, Knights Templar, and having been created by the Covenanters (http://www.sorbie.net/covenanters.htm) , those people who opposed the interference of the kings of the Stuart era messing the Scottish presbyterian church.

Gilmerton Cove is beautiful from an architectural perspective, but oh so intriguing because we know so little about how it came about. It’s a substantial place, and I’ve certainly been in houses and homes that are smaller today and they are constructed much more easily from bricks and mortar. Ignoring how it was constructed, who constructed it, and why? It’s not deep enough to be particularly secret, it doesn’t seem to have the reverence to be a holy place (although it could easily have been the location of a more subversive organisation), it doesn’t seem to be smokey or sooty enough for a blacksmiths workshop, or even for a home without some serious ventilation. If it had been populated by many people, you would expect more signs of wear and tear. It doesn’t look abused, but carefully looked after, and remarkably clean.

Please, go and see Gilmerton Cove (http://www.gilmertoncove.org.uk/)  for yourself and see if you can solve the mystery!


Joining Continuent

I’ve just completed my first month here at Continuent, strangely back into the MySQL ecosystem which I have been working in for some time before I joined CouchOne, and then Couchbase, two and half years ago. Making the move back to MySQL is both an experience, and somehow, comfortable…

Continuent produce technology that makes for easier replication between MySQL servers and, more importantly, more flexible solutions when you need to scale out by providing connector and management functionality for your MySQL cluster. That means that you can easily backup, add slaves, and create complex replication scenarios such as multi-master, and even multiple-site, multiple-master topologies. This functionality is split over two products, Continuent Tungsten, which is the cluster management product, and the open source Tungsten Replicator, which provides the basic replication functionality.

Those who know me well will know that I am no fan of the native MySQL replication, and that’s almost entirely because of the complexities of first of all getting it to work, followed by keeping it working, and ultimately because of the variability of the replication in the first place. There’s no reliable way to know if the replication stream has successfully been applied to the slaves or, from a client perspective, how far behind slaves are so that you can make an educated guess about which slave you should be talking to. Let’s not even get into the complexities of having to handle the read/write splitting required to make the master/slave relationship work in the first place.

Continuent solves this problem by using the binary log stream from MySQL, but handling the transfer and application of those bin log entries. Using this method enables Continuent to monitor and manage the replication process. Continuent knows when a statement has been applied to a slave, and it can work to ensure that the application of the changes is applied. With Continuent Tungsten, we go a stage further and provide a connector that sits between your application servers and your MySQL servers. Because Continuent Tungsten handles the replication, it knows the cluster topology, and can redirect queries to the master or the slave, and handle failures by directing the client queries to working slaves. Like all good software, it’s simple, but very very effective, and ergo very powerful.

So what am I doing at Continuent? Building out the documentation and helping users to help themselves, in combination with working with the developers to make sure that the software is as easy, intuitive, and foolproof to use as possible. In the short term, that means ensuring we have the core documentation required to get Continuent working for you.

If there’s more information you need, or something you specifically want in the documentation, let me know.

UC2009: On the Starting Blocks

Despite an annoying 3 hour flight delay from Heathrow (and no, I wasn’t connecting there, I was leaving from there), I’m here in San Francisco and Santa Clara again ready for the MySQL User Conference 2009.

I obviously have my four presentations to get through, and there will be plenty of other stuff going on at the conference both in terms of other presentations, the show floor, the booths, and the Birds of a Feather sessions (which are terrific fun).

But mostly, I see the UC2009 as the best opportunity to meet up with both other MySQL/Sun people, our customers, and the community at large and talk about the thing we are all passionate about – MySQL and the technologies surrounding it.

And I don’t care if that sounds goofy. Nothing beats talking to face to face with like minded individuals, and one thing that MySQL – and Sun – seems to engender is an extreme passion about the products we deliver that I don’t always see in other products or companies. That means the talk is always interesting and intelligent, and, when it needs to be, good fun.

To anybody attending, welcome to the fun and enjoy the experience. To those not coming, you really are missing something.

MySQL Conf 2009 Preview: Scalability and HA Tutorial

Like most people, and with just over a week to go before the conference, I’m putting the finishing touchs on my various presentations.

First up for me, on Monday afternoon, is my tutorial: Scale Up, Scale Out, and High Availability: Solutions and Combinations.

What will be doing?

Very simply: Looking at every potential solution for maximum scalability and availability for your database environment.

If you are attending, be prepared to:

  • Expand your mind as we think about scaling up.
  • Expand your horizons as we think about scaling out.
  • Divide and conquer, as we think about high-availability.

We’re not not hands on in this session – but I will expect you to be brains on!