Hadoop and ETL

My last post (here) blathered about the effect that Hadoop must have on database vendor profits. An associate wrote me with the reminder that Hadoop is also impacting revenues and profits of ETL companies.

If you think about Hadoop as both an inexpensive staging area for an EDW and as a parallel compute engine that can transform ungoverned, extracted data and load it into a governed EDW platform… then you are just one thought from realizing that these two functions have heretofore been in the domain of ETL… and that moving these functions to Hadoop might have an effect in the ETL space.

I do not believe that ETL tools will go away… but they may become just the GUI development environment that lets you quickly develop transformations and connect them into an end-to-end ETL process. The scheduling, processing engine, and monitoring could then be handled by the Hadoop eco-system.

Here is the idea from a previous post.

About five years ago the precursor to Alpine Data Labs, then an EMC Greenplum subsidiary, was developing a GUI for analytics that connected processes and I suggested they spin the product both into analytics and into ETL… I’ll have to look and see where they are these days…

A New Way of Thinking About EDW Federation

There is a new way to think about data warehouse architecture. The Gartner Group calls it a logical data warehouse and it uses database federation to dynamically integrate a universe of data warehouses, operational data stores, and data marts into a single, united, structure. This blog has suggested that there is a special case of the logical data warehouse that uses Hadoop to provide a modern data warehouse architecture with significant economic advantages (see here, here, and here).


This is the second post inspired by my chats with Bityota… and sort of, but not altogether, commercial in nature (the first post is here). That is, Bityota will use these posts in their collateral… but you won’t see foam about their products in the narrative below.

– Rob


The economics are driven by the ability, through database federation, to place tables on a less expensive database platform. In short, the aim is to place data on the least expensive platform that still provides enough performance to satisfy service level agreements (SLAs). In the case of the modern data warehouse architecture this means placing older, colder, data on Hadoop where the costs may be $1000/TB instead of having all of the data in a single data warehouse platform at a parallel RDBMS price point of $35,000/TB. Federation allows these two layers to seem as one to any program or end-user.

This approach may be thought of as a data life cycle infrastructure that has significantly more economic power that the hardware based life cycles suggested by database vendors to date. Let’s consider some of the trade-offs that define the hardware approach and the Hadoop-based approach.

The power of Hadoop federation comes from its ability to manage data placement at a macro level. Here, data is placed appropriately into a separate database management system running on differentiated hardware so that the economics of the entire infrastructure: hardware, software, and network can be optimized. It is even possible to add a third or fourth level to provide more fine-grained economic optimization. But this approach come at a cost. Each separate database optimizes queries at the database level. Despite advances in federation software technology this split optimization cannot optimize many queries. The optimization is not poor, but it is not optimal optimization. The global optimization provided by a single DBMS will almost always out-perform federated optimization.

The temperature-based optimization touted by some warehouse vendors provides good global optimization. To date a single DBMS must run on a homogeneous hardware platform with a single price point. Queries run optimally but the optimization can only twiddle around hardware details placing data in memory or on an SSD device or on the faster portion of a disk platter.

Figure 7. Federated Elastic Shared-nothing IaaS
Figure 7. Federated Elastic Shared-nothing IaaS

To eliminate this unfortunate trade-off: good optimization over minor hardware capabilities or fair optimization over the complete hardware eco-system we need a single DBMS that can run queries over a heterogeneous mix of hardware. We need a single database management system, with global query optimization, that can execute queries over multiple layers of hardware deployed in the cloud. We can easily imagine a multi-layered data warehouse with queries federated over several AWS offerings with hotter data on fast nodes that are always available, with warm data on less expensive nodes that are always available, and with cold historical data on inexpensive nodes that come online in processing windows so that you pay for the nodes only when you need them. Figure 7 shows a modern data warehouse deployed across an Amazon cloud.

This different way of thinking about a logical data warehouse is exciting… and a great example of how cloud computing may change everything in the database and data warehouse space.

Open Source is Not a Market…

This post is more about the technology business than about technology… but it may be relevant as you try to sort out winners and losers… and this sort of sorting is important if you consider new companies who may, or may not, succeed in the long run.

To make my point let us do a little thought experiment. Imagine a company doing $100M in revenue with a commercial, not open source, database product. They win the $100M in revenue by competing with Oracle, IBM, Microsoft, Teradata, et cetera… and maybe competing a little here and there with some open source products.

Let’s assume that they make 50% of their revenue from services and support, and that their average sale is $2M… so they close 25 deals a year competing in this market. Finally, let’s assume that they break-even each year and spend 20% of their revenues on R&D. The industry average for support services is 20%.. so with each $2M sale they add $400K in recurring revenue.

They are considering making their product open source. Let’s assume that they make the base product free… and provide some value-added offering that costs $200K for the average buyer. Further, they offer a support package for the same $400K/year customers currently pay. How does the math work out?

Let’s baseline against the 25 deals/year…

If they make 25 sales and every buyer buys both the support package and the value-added offer the average sale drops from $2M to $200K, sales revenue drops from $50M to $5M, the annual revenue drops from $100M to $55M… and the company loses $45M. So… starting off they need to make 225 more sales just to break even. But now it gets complicated… if they sell 5 extra deals then in the next year they earn $2M extra in support fees… so if they sell 113 extra deals in year one then in year two they have made up the entire $45M difference and they are back to break-even going forward. If it takes them 2 years to get the extra recurring revenue then they lose money in year two… but are back to break-even in year three.

From here it gets even more complicated. The mythical company above sells the baseline of 25 new copies a year with an enterprise sales force that is expensive. There is no way that the same sales force that services 25 sales/year could service 100+ extra deals. So either costs go up or the 100+ extra customers becomes unattainable. We might hope that the cost of sales will drop way off as the sales price moves to $200K. This is not unreasonable… but certainly not guaranteed. Further, if you are one of the existing sales-staff then you have to sell 10X just to make the same commission. Finally these numbers assume that every customer buys the value-add and gets enterprise-level support. Reality will be something less than this.

We might ask: is it even possible to sell 100+ more with the same product in the same market? Let us be clear that the market the database product plays in has not changed. Open Source is not a market. All we have done is reduced the sales price for the product with some hope that price is a significant driver in the market.

This is not meant as an academic exercise. Tomorrow we will consider how this thought experiment applies to Pivotal’s announcements last week… and to the future of Pivotal’s database assets (here).

Some HANA and Intel Videos

Here are two videos of me speaking from the 2013 Intel Developer Forum FYI.

The first has some technical detail:

The second is more of a PR pitch about Intel Hadoop:

I’m working with Intel on a new video with a pretty interesting storyline (at least I hope that you find it interesting?)… so stay tuned.

Rob

Hadoop Squeezes Greenplum

For several years now I have been suggesting that Hadoop will squeeze the big data RDBMSs: Teradata, Exadata, Greenplum, and Netezza… squeezing them first out of the big data end of the market and then impinging on the high-end of the EDW space. Further I have suggested that there may be a significant and immediate TCO reduction from using Hadoop with your EDW RDBMS which squeezes these product’s market faster and further.

Originally I suggested that Greenplum and Netezza would feel the squeeze first since they were embracing Hadoop directly and at the expense of their RDBMS offerings. Greenplum took this further by trying to compete on price… cutting the price of the GPDB and then introducing HAWQ, basically GPDB on HDFS, at a Hadoop DBMS price point. These moves coupled with a neglect of the EDW market where Greenplum made its name apparently has allowed Hadoop to squeeze Greenplum out of the commercial market.

My network has been humming with rumors from reliable sources for 4+ weeks now… and I am now getting confirmation from both inside and outside Pivotal that the Greenplum software will move to open source in short order. The details are being worked out… and while there may still be a change of heart… it seems to be a done deal. The buzzness plan that Greenplum embarked on prior to the EMC acquisition in 2010 has not been a commercial success.

No one is sorrier to see this than me. Greenplum had a real shot at success. It was a very solid piece of work leading the space with strong architectural extensions like data flow shared nothingness, hybrid row/columnar capabilities, and into big data applications. The ORCA optimizer had the potential to change the game again.

Greenplum was nearly profitable in 2009 running hard at Teradata and Exadata and Netezza in the EDW space. The EDW market is tough… so we have to be fair and point out that pursuing this market may have led to the same result… but a small-market analytics play was followed by an open-source Hadoop play that could only end in squeezing Greenplum. There was never really a business plan with a win at the end.

Hopefully by open sourcing Greenplum some of the sound software will make it into PostgreSQL… but dishing Greenplum into the open source space with few developers and no community dishes it into the same space that Informix, Red Brick, and others sit. I know that I suggested open sourcing Greenplum over 18 months ago (see the wacky idea here)… but the idea then, as now, amounts to capitualization. I just declared what seemed to me to be inevitable a little sooner than Pivotal.

Teradata has now further embraced Hadoop… and they run the risk of repeating the Greenplum downturn. They have a much stronger market platform to work from… but in the long run this may also be a deadly embrace.

So here is another wacky idea. The only successful business model around open source software to date (which is not to say that there is not some other model to be discovered) generates revenue from support and services and just a little software around the edges. Teradata has a support team and a services business that knows big data and is embedded in the enterprise… Cloudera, Hortonworks, and MapR are not close here. Were Teradata to go after the Hadoop market with their own distribution (not much of a barrier to entry here.. just download the Apache stuff and build a team of committers… they might even be able to pick up the Pivotal team)… they would start from a spot way ahead of the start-ups in several respects… in several hard respects. Further they have Aster IP which could qualify as software around the edges. As a Hadoop player Teradata could more easily manage how Hadoop squeezes their business, mitigate risk, and emerge a big winner in the big data space.

Related Database Fog Blog Posts:

Part 6: How Hadooped is HANA?

Now for HANA plus Hadoop… to continue this thread on RDBMS-Hadoop integration (Part 1, Part 2, Part 3, Part 4, Part 5) I have suggested that we could evaluate integration architecture using three criteria:

  1. How parallel are the pipes to move data between the RDBMS and the parallel file system;
  2. Is there intelligence to push down predicates; and
  3. Is there more intelligence to push down joins and other relational operators?

As a preface I need to include a note/apology. As you will see HANA may well have the best RDBMS-Hadoop integration in the market. I try hard not to blow foam about HANA in this blog… and I hope that the objective criteria I have devised to evaluate all of the products will keep this post credible… but please look at this post harder than most and push back if you think that I overstep.

First… surprisingly, HANA’s first release has only a single pipe to the Hadoop side. This is worrisome but easily fixed. It will negatively impact performance when large tables/files have to be moved up for processing.

But HANA includes Hadoop as a full partner in a federated data architecture using the Smart Data Access (SDA) engine inside the HANA address space. As a result, HANA not only pushes predicates but it uses cost-based optimization to determine what to push down and what to pull up. HANA interrogates the Hadoop system to gather statistics and uses the HANA optimizer to develop smart execution plans with awareness of both the speed of in-memory and the limited memory resources. When data in HANA is joined with data in Hadoop SDA effectively uses semi-joins to minimize the data pulled up.

Finally, HANA can develop execution plans that executes joins in Hadoop. This includes both joins between two Hadoop tables and joins where small in-memory tables are pushed down to execute the joins in Hadoop. The current limitation is that Hadoop files must be defined as Hive tables.

Here is the HANA execution plan for TPC-H query 19. HANA has pushed down all of the steps behind the Remote Row Scan step… so in this case the entire query including a nested loop join was pushed down. In other queries HANA will push only parts of the plan to Hadoop.

TPCH Q19 Plan

So HANA possesses a very sophisticated integration with Hadoop… with capabilities that minimize the amount of data moved based on the cost of the movement. This is where all products need to go. But without parallel pipes this sophisticated capability provides only a moderate advantage (see Part 5),

Note that this is not the ultimate in integration… there is another level… but I’ll leave some ideas for extending integration even further for my final post in the series.

Next… Part 7… considering Greenplum…

Part 4: How Hadooped is Teradata?

In this thread on RDBMS-Hadoop integration (Part 1, Part 2, Part 3) I have suggested that we could evaluate integration architecture using three criteria:

  1. How parallel are the pipes to move data between the RDBMS and the parallel file system;
  2. Is there intelligence to push down predicates; and
  3. Is there more intelligence to push down joins and other relational operators?

Let’s consider the Teradata SQL-H implementation using these criteria.

First, Teradata has effective parallel pipes to move data from HDFS to the Teradata database with one pipe per node. There does not seem to be any inter-node IO parallelism. This is a solid feature.

There is a limited ability to push down predicates… SQL-H does allow data to be partitioned on the HDFS side and it will perform partition elimination if the query explicitly calls out a predicate within a partionfilter() keyword. In addition there is an ability to project out columns using a columns() keyword to explicitly specify the columns to be returned. These features are klunky but effective. You would expect partitions to be eliminated when the partitioning column is referenced with a predicate in the query like any other query… and you would expect columns to be projected out if they are not referenced. Normal SQL predicates are applied after the data is moved over the network but before every record is written into the Teradata database.

Finally SQL-H provides no advanced capabilities to push down join operators or other functions.

The bottom line: SQL-H is a sort of klunky implementation, requiring non-ANSI-standard and non-Teradata standard SQL syntax. Predicate push down is limited but better than nothing. As you will see when we review other products, SQL-H is a  basic offering. The lack of full predicate push-down and advanced features will negatively and severely impact performance when accessing large volumes of data, Big Data, and the special SQL syntax will limit the ability to access HDFS data from 3rd party tools. This performance penalty will force customers to pre-join and pre-aggregate data in Hadoop rather than access it naturally.

Next Part 5...

References

Teradata Magazine: Hands On Dynamic Access

Doug Frazier: SQL-H Presentation

Part 1: How Hadooped is Your RDBMS?

Sorry for the comic adjective “Hadooped”?

The next few blogs will try to evaluate the different approaches to integrating Hadoop and a standard RDBMS… so the first thing I’ll try in this post is to suggest a criteria based on some architectural  choices for making the evaluation. Further, I’ll inject a little surprise and make the point by using the criteria to say something about a product that is not an integration of an RDBMS and Hadoop.

For the purposes of this let me clear that by “Hadoop” I mean at least HDFS plus MapReduce… so I will discuss integrating a parallel RDBMS with data stored in HDFS: a massively parallel file system with a programming capability included. By “integration” I mean that queries using the full set of SQL supported by the RDBMS must be available for processing queries that refer to data across the Hadoop-RDBMS divide.

Since we’ve assumed that all SQL functionality is supported the architectural issue left to solve is performance and this issue revolves on one topic: how do we minimize the cost of moving data between the two partners for a given query?

Now to get on with it…

The easiest, but not all that easy, problem involves using parallelism to move data from one system to the other… so the first criteria we will evaluate for each product will consider how parallel is their movement of data.

The next criteria involves intelligence in the RDBMS to push down some execution operators to the data layer. Of course the RDBMS must scan remote data… so in this part of the evaluation we will grade each product’s ability to push processing down to apply predicates and project the minimal amount of data up to the RDBMS.

Finally, a most intelligent product would push more than just predicates down… it would push down joins and aggregation… and the decisions around splitting processing would be fully optimized. A most intelligent product would fully federate the HDFS data into the RDBMS.

So there you have it… I will start evaluating RDBMS-Hadoop architecture by three criteria:

  • how parallel is the data movement between the RDBMS and Hadoop;
  • is there intelligence to minimize data movement by pushing the least data and the associated query plan to one system or another… this requires parallel pipes in both directions; and
  • is there intelligence to build an optimal query plan that splits steps across both systems to completely minimize the movement of data and/or optimize the compute.

And a final word on the relative strength of each criteria:

  • If we imagine a 10-node Hadoop cluster talking to a 10-node RDBMS with 10 parallel pipes and compared it to the same setup with only 1 pipe (not parallel) then we might suggest that the parallel pipes provide a 10X performance increase.
  • If we imagine intelligence that moved 100K rows rather than 10M then we might suggest that intelligent push down might provide a 100X performance increase…
  • If we had even more intelligence and further optimized processing then another 10X-100X might be possible.

So all three criteria are not equal… intelligent query planning trumps wide pipes…

Now for the surprise… in the next blog we’ll look at how Exadata’s architecture maps to these criteria… since it is a two-tiered architecture with an RDBMS tied to a parallel file system…

You can see the rest of the series here: Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8.

The Hype of Big Data

Hype Cycle for Emerging Technologies 2010
Hype Cycle for Emerging Technologies 2010 (Photo credit: marcoderksen)

As preface to this you might check out the definition I suggested for Big Data last week here… – Rob

I left Greenplum in large part because they made their mark in… and then abandoned… the  data warehouse market for a series of big hype plays: first analytics and data science; then analytics, data science, and Hadoop; then they went “all-in”, their words, on Big Data and Hadoop… and now they are part of Pivotal and in a place that no-one can clearly define… sort of PaaS where Greenplum on HDFS is a platform.

It is not that I am a Luddite… I pretend each time I write this blog that I am in tune with the current and future state of the database markets… that I look ahead now and then. I just thought that it was unlikely for Greenplum to be profitable by abandoning the market that made them. At the time I suggested to them an approach that was founded in data warehousing but would let them lead in the hyped plays… and be there in front when, and if, those markets matured.

Now, if we were to define markets in an unambiguous manner:

  • a data warehouse database is primarily accessed through one or more BI tools;
  • an analytic database is primarily accessed through a statistical tool; and
  • Hadoop requires Hadoop;

then I suspect that the vast majority of Greenplum revenues still,  3-4 years after the move away from data warehousing, come from the DW market. It is truly a shame that this is not the focus of their engineering team and their marketeers.

Gartner has called it pretty accurately in their 2013 Hype Cycle for Emerging Technologies here. Check out where Big Data is on the curve and how long until it reaches the mainstream. Worse, here is a drill-down showing the cycle for just Big Data. Look at where Data Science sits and when they expect it to plateau. Look at where SQL for Hadoop is in the cycle.

Big Data is real and upcoming… but there is no concise definition of Big Data… no definition that does not overlap technologies that have been around since before the use of the term. There is no definition that describes a technology that the Fortune 1000 will take mainstream in the next 2-3 years. Further, as I have suggested here and here, open source products like Hadoop will annihilate the commercial market for big analytic databases and squeeze hard the big EDW DBMS players. It is just not a commercially interesting space… and it may not become commercially interesting if open source dominates (unless you are a services company).

Vendors need to be looking hard at Big Data now if they want to play in 2-3 years. They need to be building Big Data integration into their products and they need to be building Big Data apps that take the value straight into the business.

Users need to be looking carefully for opportunities to use Hadoop to reduce costs… and, in highly competitive markets which naturally generate lots of machine-to-machine data, they need to look for opportunities to get ahead of the competition.

But both groups need to understand that they are on the wrong side of the chasm (see here for reference to Crossing the Chasm)… they have to be Early Adopters with a culture that supports an early adopter business model.

We all need to avoid the mistake described in the introduction. We need to find commercially viable spots in an emerging technology play where we can deliver profits and ROI to our organizations. It is not that hard really to see hype coming if you are paying attention… not that hard to be a minor visionary. It is a lot harder to turn hype into profits…

Hadoop and the EDW

Squeeze If You Feel Pain
Squeeze If You Feel Pain (Photo credit: Artotem)

Cloudera and Teradata have jointly published a nice paper here that presents an interesting perspective of how Hadoop and an EDW play together. Simply put, Hadoop becomes the staging area for “raw data streams” while the EDW stores data from “operational systems”. Hadoop then analyzes the raw data and shares the results with the EDW. Two early examples provided suggest:

  • Click stream data is analyzed to identify customer preferences that are then shared with the EDW. Note that the amount of data sent from Hadoop to the EDW would be fairly small in this case.
  • Detailed data is stored on Hadoop to build analytic models. The models are then transferred to the EDW to score sales activity data. Note that in this scenario the scored activity detail has to live in Hadoop to perform modeling… but it is unclear why it has to live in the EDW as well. I presume that scoring takes place on the EDW instead of in Hadoop for performance reasons… but maybe the data, the modeling, and the scoring should just take place in Hadoop?

The paper then positions Hadoop as an active archive. I like this idea very much. Hadoop can store archived data that is only accessed once a month or once a quarter or less often… and that data can be processed directly by Hadoop programs or shared with the EDW data using facilities such as Teradata’s SQL-H, or Greenplum‘s External Hadoop tables (not by HAWQ, though… see here), or by other federation engines connected to HANA, SQL Server, Oracle, etc.

But think about the implications on how much data has to stay in your EDW if you archive everything older than 90, or even 180, days to Hadoop. The EDW shrinks significantly and the TCO advantage to your Enterprise will be significant. This is very cool.

There is one item in the paper I disagree with, though… and another statement that I think has a very short shelf-life.

The paper suggests that indexes, materialized views, aggregate join indexes, and other tweaks are what differentiates an EDW. I believe that reliance on these structures make for a fragile EDW where only some queries can run fast. I like Teradata better when it just robustly scans fast and none of these redundant-data tuning artifacts are required (more here and here). Teradata was the original scan-fast DBMS… it is more than capable.

The paper also suggests that an EDW maintains value by including a sophisticated cost-based optimizer that uses data demographic statistics to identify an optimal query execution plan. I agree that Hadoop lacks this now… but there are several projects like Cloudera Impala that will eliminate this gap in the near term.

I believe that if you read between the lines you will see more evidence to support my belief (here) that Hadoop will squeeze the EDW vendors hard… and that the size of a squeezed EDW will then fit in an in-memory database.