Data warehousing
Analysis of issues in data warehousing, with extensive coverage of database management systems and data warehouse appliances that are optimized to query large volumes of data. Related subjects include:
DB2 workload management
DB2 has added a lot of workload management features in recent releases. So when we talked Tuesday afternoon, Tim Vincent and I didn’t bother going through every one. Even so, we covered some interesting subjects in the area of DB2 workload management, including: Read more
| Categories: Data warehousing, IBM and DB2, Netezza, Workload management | 2 Comments |
More on temp space, compression, and “random” I/O
My PhD was in a probability-related area of mathematics (game theory), so I tend to squirm when something is described as “random” that clearly is not. That said, a comment by Shilpa Lawande on our recent Flash/temp space discussion suggests the following way of framing a key point:
- You really, really want to have multiple data streams coming out of temp space, as close to simultaneously as possible.
- The storage performance characteristics of such a workload are more reminiscent of “random” than “sequential” I/O.
If everybody else is cool with it too, I can live with that. 
Meanwhile, I talked again with Tim Vincent of IBM this afternoon. Tim endorsed the temp space/Flash fit, but with a different emphasis, which upon review I find I don’t really understand. The idea is:
- Analytic DBMS processing generally stresses reads over writes.
- Temp space is an exception — read and write use of temp space is pretty balanced. (You spool data out once, you read it back in once, and that’s the end of that; next time it will be overwritten.)
My problem with that is: Flash typically has lower write than read IOPS (I/O per second), so being (relatively) write-intensive would, to a first approximation, seem if anything to disfavor a workload for Flash.
On the plus side, I was reminded of something I should have noted when I wrote about DB2 compression before:
Much like Vertica, DB2 operates on compressed data all the way through, including in temp space.
| Categories: Data warehousing, Database compression, IBM and DB2, Vertica Systems | 5 Comments |
Vertica’s innovative architecture for Flash, plus more about temp space than you perhaps wanted to know
Vertica is announcing:
- Technology it already has released*, but has not published any reference architectures for
- A Barney partnership**
In other words, Vertica has succumbed to the common delusion that it’s a good idea to put out half-baked press releases the week of TDWI conferences. But if we look past that kind of all-too-common nonsense, Vertica is highlighting an interesting technical story, about how the analytic DBMS industry can exploit solid-state memory technology.
*Upgrades to Vertica FlexStore to handle Flash memory, actually released as part of Vertica 4.0
** With Fusion I/O
To set the context, let’s recall a few points I’ve noted in the past:
- Solid-state memory’s price/throughput tradeoffs obviously make it the future of database storage.
- The Flash future is coming soon, in part because Flash’s propensity to wear out is overstated. This is especially true in the case of modern analytic DBMS, which tend to write to blocks all at once, and most particularly the case for append-only systems such as Vertica.
- Being able to intelligently split databases among various cost tiers of storage – e.g. Flash and disk – makes a whole lot of sense.
Taken together, those points tell us:
For optimal price/performance, analytic DBMS should support databases that run part on Flash, part on disk.
While all this is a future for some other analytic DBMS vendors, Vertica is shipping it today.* What’s more, three aspects of Vertica’s architecture make it particularly well-suited for hybrid Flash/disk storage, in each case for a similar reason – you can get most of the performance benefit of all-Flash for a relatively low actual investment in Flash chips: Read more
| Categories: Columnar database management, Data warehousing, Database compression, Solid-state memory, Vertica Systems | 10 Comments |
Teradata’s future product strategy
I think Teradata’s future product strategy is coming into focus. I’ll start by outlining some particular aspects, and then show how I think it all ties together.
Read more
| Categories: Business intelligence, Data warehouse appliances, Data warehousing, Kickfire, Microstrategy, Solid-state memory, Storage, Teradata | 2 Comments |
Big Data is Watching You!
There’s a boom in large-scale analytics. The subjects of this analysis may be categorized as:
- People
- Financial trades
- Electronic networks
- Everything else
The most varied, interesting, and valuable of those four categories is the first one.
| Categories: Analytic technologies, Aster Data, Data warehousing, Investment research and trading, Log analysis, MapReduce, RDF and graphs, Specific users, Telecommunications, Web analytics | 3 Comments |
Links and observations
I’m back from a trip to the SF Bay area, with a lot of writing ahead of me. I’ll dive in with some quick comments here, then write at greater length about some of these points when I can. From my trip: Read more
Notes on EMC’s Greenplum subsidiary
I spent considerable time last week with my clients at both Greenplum and EMC (if we ignore the fact that the deal has closed and they’re now the same company). I also had more of a hardcore engineering discussion than I’ve had with Greenplum for quite a while (I should have been pushier about that earlier). Takeaways included:
- This is starting off as a honeymoon deal. Everything Greenplum was planning to do is being continued. Additional resources are being poured into Greenplum to do more.
- Some Greenplum execs seem to envision staying long term, some seem to envision moving on to their next startups. The ones who envision moving on are, however, going to work hard first to make the merger a success.
- Greenplum has, for quite a while, had more of an advanced analytics/embedded predictive modeling story than I realized. Bad on them for not fleshing it out more in marketing and product packaging alike.
- Greenplum both denies the concurrency problems I previously noted and also has a very credible story as to how it will eliminate them. Seriously, Greenplum tells of one customer that routinely runs 150 simultaneous queries – on what I think is not a terribly big system — and a number of POCs (Proofs of Concept) that simulated similar levels of concurrency.
| Categories: Analytic technologies, Data warehousing, EMC, Greenplum | Leave a Comment |
Teradata, Xkoto Gridscale (RIP), and active-active clustering
Having gotten a number of questions about Teradata’s acquisition of Xkoto, I leaned on Teradata for an update, and eventually connected with Scott Gnau. Takeaways included:
- Teradata is discontinuing Xkoto’s existing product Gridscale, which Scott characterized as being too OLTP-focused to be a good fit for Teradata. Teradata hopes and expects that existing Xkoto Gridscale customers won’t renew maintenance. (I’m not sure that they’ll even get the option to do so.)
- The point of Teradata’s technology + engineers acquisition of Xkoto is to enhance Teradata’s active-active or multi-active data warehousing capabilities, which it has had in some form for several years.
- In particular, Teradata wants to tie together different products in the Teradata product line. (Note: Those typically all run pretty much the same Teradata database management software, except insofar as they might be on different releases.)
- Scott rattled off all the plausible areas of enhancement, with multiple phrasings – performance, manageability, ease of use, tools, features, etc.
- Teradata plans to have one or two releases based on Xkoto technology in 2011.
Frankly, I’m disappointed at the struggles of clustering efforts such as Xkoto Gridscale or Continuent’s pre-Tungsten products, but if the DBMS vendors meet the same needs themselves, that’s OK too.
The logic behind active-active database implementations actually seems pretty compelling: Read more
| Categories: Clustering, Continuent, Data warehousing, Solid-state memory, Teradata, Theory and architecture, Xkoto | 5 Comments |
Advice for some non-clients
Edit: Any further anonymous comments to this post will be deleted. Signed comments are permitted as always.
Most of what I get paid for is in some form or other consulting. (The same would be true for many other analysts.) And so I can be a bit stingy with my advice toward non-clients. But my non-clients are a distinguished and powerful group, including in their number Oracle, IBM, Microsoft, and most of the BI vendors. So here’s a bit of advice for them too.
Oracle. On the plus side, you guys have been making progress against your reputation for untruthfulness. Oh, I’ve dinged you for some past slip-ups, but on the whole they’ve been no worse than other vendors.’ But recently you pulled a doozy. The analyst reports section of your website fails to distinguish between unsponsored and sponsored work.* That is a horrible ethical stumble. Fix it fast. Then put processes in place to ensure nothing that dishonest happens again for a good long time.
*Merv Adrian’s “report” listed high on that page is actually a sponsored white paper. That Merv himself screwed up by not labeling it clearly as such in no way exonerates Oracle. Besides, I’m sure Merv won’t soon repeat the error — but for Oracle, this represents a whole pattern of behavior.
Oracle. And while I’m at it, outright dishonesty isn’t your only unnecessary credibility problem. You’re also playing too many games in analyst relations.
HP. Neoview will never succeed. Admit it to yourselves. Go buy something that can. Read more
Microstrategy technology notes
Earlier this week, Microstrategy made Mark LaRow available to talk about technology. The proximate reason was my recent mention of Microstrategy’s mobile BI emphasis, but we also touched on Microstrategy’s approach to in-memory business intelligence and some other subjects. We didn’t go into the depth of a similar conversation I had recently with Qlik Technologies, but I found it quite interesting even so.
Highlights of the in-memory BI discussion included:
- Microstrategy’s in-memory BI data structure is some kind of simple array, redundantly called a “vector array.” A more precise description was not available.
- While early versions of the capability have been around since 2002, Microstrategy’s in-memory BI capability only got serious with Microstrategy 9, which was released in Q1 of 2009. In particular, Microstrategy 9 was the first time in-memory BI had full security.
- Mark says a core reason for having their own in-memory BI is because Microstrategy has more smarts to predict which aggregates will or won’t be needed. Strictly speaking, that can’t be argued with. Vendors like Infobright would argue they come close enough to that ideal as to make little practical difference – but I’m also cheating by naming Infobright, which is particularly focused in that direction.
- Microstrategy in-memory BI compresses data by about 2X. Mark didn’t know which compression algorithm was used.
- The limitation on what’s in-memory is, of course, how much RAM you can fit on an SMP box. Microstrategy has seen up to ½ terabyte deployments.
- In-memory Microstrategy data structures are typically built during the batch window, for performance reasons. This is not, strictly speaking, mandatory, but I didn’t get a sense that Microstrategy was being used for much that resembled real-time business intelligence.
- Mark said Microstrategy has no interest in using solid-state memory to expand the reach of its in-memory BI. Frankly, if Microstrategy doesn’t change that stance, it’s in-memory BI capabilities are unlikely to stay significant for too many years.
Another key subject we discussed was Microstrategy’s view of dashboards. Read more