DavidBirmingham 2700043KNU Tags:  port performance functional migration suspect 100x netezza 1 Comment 4,657 Views
After completing another migration from a traditional, general-purpose RDBMS to the Netezza technology, I visited a friend who had several artifacts in his home that had to be the strangest things I'd ever seen.
Now I'd heard of genetically altered cat fur, you know, buying a cat online while picking the fur color of your choice (blue, lavender, teal - etc). Seems like an odd thing to do to a cat. I like cats and dogs both, so don't imagine that this blog essay attempts to take sides. Some folks are downright serious on their choice of pet, so I'll smooth that fur wherever I can.
Back to the hairless cats. I asked him "Where did you find these? And what happened to your other cats?" And he laughed, "That's a funny story. These are my cats, but I had to shave them." To this, I rolled my eyes, wondering where this was about to lead. He told the tale:
"We took a vacation down south and put the cats in kennels in the back of the truck. The round-trip took a toll on their fur and matted up everything from head to toe. Weeks later, the cat fur had not smoothed out. The kids had been brushing it out but it wasn't working. And if you think they look ridiculous shaved, you have no idea how silly they looked with their hair matted."
"So you shaved them?" I asked.
"Sure" he said, "Seems practical right? Just get rid of the matted hair altogether. Teasing it apart would have taken, well, years of time. Their fur will grow back out soon enough"
"Aren't there, you know, shampoos and stuff for that? I mean, shaving seems a little extreme."
"Tried all that. Bad thing about it, mats are bad for cats - they cause infections and all kinds of nasty side effects. Best to just shave it all and be done with it."
Laughing on the inside, I thought a bit about how we have to decompose and de-engineer an organically-grown data warehouse. Some would suggest porting (forklifting) the whole thing over "as is". Like taking a matted-hair cat and moving them from one house to another. It changes the venue for the cat, but doesn't help the cat at all. It's still sick and getting sicker from the mats. Such folks "tell a tale" of the success of their migration derring-do. But they are like nomads. Hunting the game until there's no more, then pulling up stakes to find another place to burn out. Forklift-migrations have value only to the ones who are doing the migrating, not the recipients. No sooner will they tie a bow on it than someone will request a change, and we will discover what we already knew: The original data model (now the new data model) isn't very resilient to change no matter where it is hosted.
We realize we have ported both the good and the bad from the old system, when we had the opportunity to port the good and leave the bad behind. We essentially are agreeing that we are about to standardize on the past and then accommodate the future, rather than a better approach: standardize on the future and accommodate the past.
Many years ago, at one site we had to carefully tease-apart the data and the stored procedured to find out what they were actually doing. Unfortunately we had carved up the work for several teams rather than reviewing it together. Had we done this, we would have discovered that the stored procs executed in chains of work, and that many of the chains were copy-pasted from one original chain that was too "matted" to risk breaking. So they copied-and-modified this chain to perform the new functionality. Enough of these and we see how the stored procedure doesn't benefit us (at all) for back-end data processing. In fact, we strongly suggest people use stored procs in Netezza for BI-adaptation and optimization, for the presentation layer. But not for the back end. Stored procs are not operationally viable for a wide range of reasons. It's even funny how folks move from one technology to another and try to replicate the stored procedure logic as a knee-jerk exercise, without realizing how flawed it really is. Perhaps the Netezza stored proc will run a lot faster. Trust me, performance is the least of your worries.
So once we converged the teams together, these themes started popping out like rabbits. By the end of the first day we are all laughing at the sheer level of redundancy in the back end. But not particularly surprised at the outcome. We'd seen it in lots of places before, but not so bad.
Of course, it never once occurred to us that we would port these hundreds of stored procs over to the new system. Rather we would functionally specify what they are doing now, and leverage tools to accommodate the vast majority of the functionality, only building what was left over. I mean, this is a standard functional port, why complicate things? Forklifting into a Netezza machine will certainly yield 10x performance, so why the beef? Without optimizing the data structures and processes to leverage Netezza's power, we might get 10x but leavel 100x on the table. Is this a good tradeoff?
Well, true to form, someone had the capacity to complicate things. He whipped out a spreadsheet and calculated the cost of the hundreds-of-stored-procs in the original system, not realizing we were planning to reduced these to maybe fifteen operations at most. Spreadsheet calculator in-hand, he estimated that it would take 24 people, 8 months, to handle on these stored procs. I sat back in my seat, stunned, because he was costing a project we weren't about to undertake. Rather, building out 15 or so operations would require a handful of people and 90 days at the outside. But also true to form, the project principals saw visions of sugar plums (another word for sales-comp) that got in the way of their better judgment. They actually went to the client with these inflated numbers, he rejected their proposal outright and gave the business to someone else. It's easy to lose a deal when the client sees the inflation on-the-page.
But what our "spreadsheet guy" missed, was that we weren't about to embark on a journey of finding a home for each stored proc (we already knew this had no value, and the client knew it too). He believed that we intended to bring the matted-cats into the house and put them on pillows, when we intended to pick the cats we wanted to keep, and shave them.
Okay, that's a strange analogy, but we had no intention whatsover of accepting all that convoluted spaghetti as the foundation for the go-forward system.
Netezza gives us the capacity - to simplify. We keep the parts we consider valuable (the cat) and get rid of all the mess that keeps the cat sick and unhappy. Taking only the functions we want, we then reconstruct (let the hair grow back out) only what we want to keep, and take the opportunity to apply some solid architectural principles and likewise capitalize on the strengths of the Netezza platform.
In the end, if we really have a platform that is standardized on the future, but accommodates the past, we also have something else that is even more powerful: A simpler, stronger engine that is ready to grow in functionality, adapting to our changing needs. The old system was never built with this kind of vision or priority, because the power wasn't there to affect it anyhow.
DavidBirmingham 2700043KNU Tags:  puredata best practice netezza universe migration enzee 4,113 Views
Many months ago I sat for some interviews essentially distilling the content of the Best Practice Sessions we executed in "deep dive" form at the Enzee Universe in Boston for several years.
Of course, time was always short and we were never able to touch on all the subjects in all the topics. As an example, the topic of Migration was jam-packed into one hour with a follow-on Q&A of 30 minutes. As one can see by the content of the monologues, there was always three or more hours of material we could never get to.
Now available on Amazon in a four-part "mini-series".
DavidBirmingham 2700043KNU Tags:  pda conversion netezza analytics performance migration 1,341 Views
Many years ago we encountered an environment where the client wanted the old system refactored into the new. The "new" here being the Netezza platform and the "old" here being an overwhelmed RDBMS that couldn't hope to keep up with the workload. So the team landed on the ground with all hopes high. The client had purchased the equivalent of a 4-rack striper for production and a 1-rack Striper for development. Oddly, the same thing happened here as happens in many places. The 4-rack was dispatched to the protected production enclave and the 1-rack was dropped into the local data center with the developers salivating to get started. And get started they did.
The first team inherited about half a terabyte of raw data from the old system and started crunching on it. The second team, starting a week later, began testing on the work of the first team. A third team entered the fray, building out test cases and a wide array of number-crunching exercises. While these three teams dogpiled onto and hammered the 1-rack, the 4-rack sat elsewhere, humming with nothing to do.
We know that in any environment we encounter, with any technology we can name, the development machines are underpowered compared to the production environment. And while the production environment has a lot of growing priorities for ongoing projects, we don't have this scenario for our first project, do we? Our first project has a primary, overarching theme: it is a huge bubble of work that we need to muscle-through with as much power as possible. That "as much as possible" in our case, was the 4-rack sitting behind the smoked glass, mocking us.
And this is the irony - for a first project we have a huge "first-bubble" of work before us that will never appear again. the bubble includes all the data movement, management and backfilling of structures that we will execute only once, right? Really? I've been in places where these processes have to be executed dozens if not hundreds of times in a development or integration environment as a means to boil out any latent bugs prior to its maiden - and only - conversion voyage. But is this a maiden-and-only voyage? Hardly - typically the production guys will want to make several dry runs of the stuff too. We can multiply their need for dry runs with ours, because we have no intention of invoking such a large-scale movement of data without extensive testing.
And yet, we're doing it on the smaller machine. No doubt the 1-rack has some stuff - but I've seen cases where it might take us two weeks to wrap up a particularly heavy-lifting piece of logic. If we'd done this on the larger 4-rack, we would ahve finished it in days or less. Double the power, half the time-to-deliver (when the time is deliver is governed by testing)
In practically every case of a data warehouse conversion, the actual 'coding' and development itself is a nit compered to the timeline required for testing. I've noted this in a number of places and forms, in that the testing load for a data warehouse conversion is the largest and most protracted part of the effort. And if testing (as in our case) is largely loading, crunching and presenting the data, we need the strongest possible hardware to get past the first bubble. A data conversion project is a "testing" project more so than a "development" project, and with the volumes we'll ultimately crunch, hardware is king.
But I've had this conversation with more people than I can count. Why can't you deploy the production environment with all its power, for use in getting past the first bubble, then scratch the system and deploy for production? What is the danger here? I know plenty of people, some of them vendor product engineers, who would be happy to validate such a 'scratch' so that the production system arrives with nothing but its originally deployed default environment.
Yet another philosophy is that we would pre-configure the machine for production deployment, but nobody likes developers doing this kind of thing in a vacuum. They would rather see deployment/implementation scripts that "promote" the implementation. I'm a big fan of that, too, for the first and every following deployment. That's why I would prefer we used the production-destined system to get past the first-bubble-blues, then scratch it, and get the original environment standing up straight, and only then treat it as an operational production asset.
Most projects like this have a very short runway in their time-to-market, and we do a disservice to the hard-working folks who are doing their best to stand up this environment, They need all the power they can get, especially when they enter the testing cycle.
And for this, it's an 80/20 rule for every technical work product we will ever produce. Take a look sometime at what it takes to roll out a simple Java Bean, or a C# application, or a web site. Part of the time is spent in raw development, and part of it in testing. If I include the total number of minutes spent by the developer in unit testing, and then by hardcore testers in a UAT or QA environment, and it is clear that the total wall-clock hours spent in producing quality technology breaks into the 80/20 rule - 20 percent of the time is spent in development, and 80 percent in testing.
And if the majority of the time is spent in testing, what are we testing on Enzee space? The machine's ability to load, internally crunch and then publish the data. On a Netezza machine, this last operation is largely a function of the first two. But we have to test all the loading don't we? And when testing the full processing cycle we have to load-and-crunch in the same stream, no? What does it take to do this? Hardware, baby, and lots of it.
I can say that multiple small teams can get a lot of "ongoing" work done on a 1-rack, no doubt a very powerful environment. I can also say that a machine like this, for multiple teams in the first-bubble effort, will gaze longingly at the 4-rack in the hopes they can get to it soon, because so much testing is still before them, and they need the power to close.
What are some options to make this work? Typically the production controllers and operators don't like to see any "development" work in the machines that sit inside the production enclosure. They want tried-and-tested solutions that are production-ready while they're running. At the same time, they have no issues with allowing a pre-production instance into the environment because they know a pre-production instance is often necessary for performance testing. Here's the rub: the entire conversion and migration is one giant performance test! So designating the environment as pre-production isn't subtle, nuanced, disingenuous or sneaky - it accurately defines what we're trying to do. It's a performance-centric conversion of a pre-existing production solution, now de-engineered for the Netezza machine. As I noted, development is usually a nit, where the testing is the centerpiece of the work.
With that, Netezza gives us the power to close, to handily muscle-through this first-bubble without the blues - we only hurt ourselves with "policies" for the environment that are impractical for the first-bubble.
This brings us full-circle yet again to a common problem with environments assimilating a Netezza machine. The scales and protocols put pressure on policies, because those policies are geared for general-purpose environments. There's nothing wrong with the policies, they protect things inside those general-purpose environments. But the same policies that protect things in general-purpose realm actually sacrifice performance in the Netezza realm. Don't toss those policies - adapt them.