Netezza
Analysis of Netezza and its data warehouse appliances. Related subjects include:
IBM and Teradata too
If I had to name one company with the broadest possible overview of the data warehouse engine market, it would have to be IBM. IBM offers software and hardware, services-heavy deals and quasi-appliances, OLTP and ROLAP, shared-everything and shared-nothing, integrated-(almost)-everything and best-of-breed. So their ROLAP recommendations, while still rather self-serving (just as any other vendor’s would be), are at least somewhat more than just a case of “Where you stand depends upon where you sit.”
At its core, the current IBM ROLAP story is:
- Shared nothing MPP.
- Flexible indexing, lightly applied.
- Normalized data models.
- Thoroughly mixed workloads.
- Preconfigured hardware.
Here’s some more detail, about IBM and other vendors alike.
| Categories: Data warehouse appliances, Data warehousing, DATAllegro, IBM and DB2, Netezza, Teradata | 2 Comments |
Relational data warehouse Expansion (or Explosion) Ratios
One of the least understood aspects of data warehouse technology is what may be called the
Expansion Ratio = (Total disk space used, except for mirroring) / (Size of the base database).
This is similar to the explosion ratio discussed in the OLAP Report’s justly famous discussion of database explosion, but I’m going with my own terminology because I don’t want to be tied to their precise terminology, nor to their technical focus. Expansion Ratios are hotly debated, with some figures being:
- Teradata claims an Expansion Ratio of 8-9X for Oracle, 6X for DB2 (open system version), and 2.5X for Teradata. The underlying source is data warehouses they’ve replaced, so there may be a bias toward out-of-control warehouses on the part of their competitors.
- An anonymous appliance vendor exec said to me off the top of his head that Oracle has 6-8X Expansion Ratios.
- Oracle’s TPC-H submissions in the largest size range (10 terabytes) have 9.7-10.5X Expansion Ratios, if I’m reading the TPCs correctly.
- Oracle cites a survey of 8 customers with 10-60 Tb database size in which the Expansion Ratio works out to 1.6X. (More on this anomalous result below.)
I don’t have actual figures from Netezza and DATallegro, but I imagine they’d come out lower than 2X, possibly well below.
| Categories: Data warehouse appliances, Data warehousing, Database compression, DATAllegro, IBM and DB2, Netezza, Oracle, Teradata | 9 Comments |
Logless, lockless Netezza more carefully explained
I talked at length with Bill Blake and Doug Johnson of Netezza today. (Bill is exactly the guy I complained of previously having had my access cut off to.) One takeaway was a clarification of their approach to transactions, which sounds even cooler than I first thought. It’s actually not a new idea; they just timestamp rows with CreateIDs and DeleteIDs, then exploit those to the hilt. Actually, it seems like this approach would be interesting in OTLP as well, although I’m not aware of it being used in any of the more successful OLTP DBMS systems. (Yes, this is an open invitation to fans of less-established DBMS products to tell me of their virtues, preferably in a flame-free manner.)
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| Categories: Data warehouse appliances, Netezza | 5 Comments |
Oracle and Microsoft in data warehousing
Most of my recent data warehouse engine research has been with the specialists. But over the past couple of days I caught up with Oracle and Microsoft (IBM is scheduled for Friday). In at least three ways, it makes sense to lump those vendors together, and contrast them with the newer data warehouse appliance startups:
- Shared-everything architecture
- End-to-end solution story
- OLTP industrial-strengthness carried over to data warehousing
In other ways, of course, their positions are greatly different. Oracle may have a full order-of-magnitude lead on Microsoft in warehouse sizes, for example, and has a broad range of advanced features that Microsoft either hasn’t matched yet, or else just released in SQL Server 2005. Microsoft was earlier in pushing DBA ease as a major product design emphasis, although Oracle has played vigorous catch-up in Oracle10g.
| Categories: Data warehouse appliances, DATAllegro, EAI, EII, ETL, ELT, ETLT, IBM and DB2, Microsoft and SQL*Server, Netezza, Oracle, Parallelization, Teradata | 1 Comment |
Data warehouse and mart uses – a tentative taxonomy
I’ve been posting a lot recently about the diverse database technologies used to support data warehousing. With the marketplace supporting such a broad range of architectures, it seems clear that a lot of those architectures actually deserve to thrive, presumable each in a different kind of usage scenario. So in this post I’ll take a pass at dividing up use cases for data warehouses, and suggesting which kinds of data warehouse management technologies might do the best job of supporting them. To start with, I’ve divided things into a number of buckets:
- Pinpoint data lookup
- Constrained query and reporting
- Cube-filling calculations
- Hardcore tabular data crunching
- Text and media search
- Specialty areas, such as relationship analytics
| Categories: Data warehouse appliances, Data warehousing, DATAllegro, IBM and DB2, MOLAP, Netezza, Teradata | 1 Comment |
Competitive issues in data warehouse ease of administration
The last person I spoke with at the Netezza conference on Tuesday was a customer/presenter that the company had picked out for me. One thing he said baffled me — he claimed that Netezza was a real appliance vendor, but DATallegro wasn’t, presumably due to administrability issues. Now, it wasn’t clear to me that he’d ever evaluated DATallegro, so I didn’t take this too seriously, but still the exchange brought into focus the great differences between data warehouse products in the area of administration. For example:
- Netezza has no indices at all. And no caches. And the hardware is preconfigured. This all makes administration pretty simple.
- DATallegro has almost no indices, and also has preconfigured hardware. But it has some partitioning, optionally.
- Teradata also has preconfigured hardware. It does have indices, but rather simple ones. Plus it has join indices. And it has a few more configuration options in other areas (e.g., block size) than the other appliance vendors. (Yes, I count Teradata among the appliances.)
- If you go through all the fuss of installing SAP’s applications and BI technology anyway, the incremental administration of just SAP BI Accelerator is pretty light.
- Oracle and IBM have mammothly complex indexing options, but have put large amounts of work into tools to lessen the resulting administrative burden.
- IBM offers preconfigured hardware units to simplify some installation issues.
- Come to think of it, I don’t really know how hard it is to administer columnar systems (e.g., Sybase IQ).
| Categories: Data warehouse appliances, Data warehousing, DATAllegro, Greenplum, IBM and DB2, Netezza, Oracle, SAP AG, Teradata | 3 Comments |
Teradata vs. the new appliance vendors, technically
Todd Walter and Randy Lea of Teradata gave generously of their time today, ducking out of their user conference, and shared their take on issues we’ve been discussing here recently. Overall, Teradata response to the data warehouse appliance guys is essentially: “Well, those may be fine for specific queries, or for data marts, but in true blended enterprise data warehouse workloads we’re superior, including in performance.”
Specific takeaways included:
| Categories: Data warehouse appliances, DATAllegro, Netezza, Teradata | 4 Comments |
No locks, no logs — no problem?
There’s another cool-sounding part to the Netezza story, which straddles their chips and their software: The FPGA takes over the work of assuring database consistency. If the system attempts to read and write a record at the same time, the FPGA keeps thing straight. This eliminates the need for locks — at least if you don’t care about transactional integrity — and some of the reason for logs. (I guess that in lieu of any kind of rollback/rollforward they just rely on failover to mirrored disks.)
This isn’t exactly the way one would want to do OLTP, and in general my head is shaking as I write this — but it sure seems to suffice for some rather demanding data warehouse users.
| Categories: Data warehouse appliances, Netezza, Theory and architecture | 2 Comments |
Netezza’s chip story
In addition to its software story, Netezza of course has a rather unique chip story. Where other vendors might have standard disk controllers and high-powered microprocessors, Netezza respectively has a FPGA (Field-Programmable Gate Array) and lesser microprocessor (PowerPC). Netezza claims that two major advantages of these choices are:
- 5X throughput/performance improvement
- Much lower heat and power consumption.
The main function of the FPGA, other than generically getting data on and off disk, is to restrict and project tables (i.e., execute single-table WHERE clauses). Netezza claims that their FPGAs can perform these operations on the streaming data at least as quickly as an expensive, hot, power-hungry top-end microprocessor would, and indeed faster. The key word is “streaming”, which they contrast to the microprocessor’s need to get the data in and then back out of RAM (cache or otherwise).
I’ll be interested to see whether somebody can muster a ringing refutation to Netezza’s claims.
| Categories: Data warehouse appliances, Netezza | 12 Comments |
Netezza vs. conventional data warehousing RDBMS
For various reasons, I’m not going to try to give a comprehensive overview of the Netezza story. But I’d like to highlight four points that illustrate a lot of the difference between Netezza’s architecture and that of more conventional data warehousing DBMS.
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| Categories: Data warehouse appliances, Data warehousing, DATAllegro, Netezza | 6 Comments |