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:
Boston Big Data Summit keynote outline
Last month, Bob Zurek asked me to give a talk on “Big Data”, where “big” is anything from a few terabytes on up, then moderate a panel on cloud computing. We agreed that I could talk just from notes, without slides. So, since I have them typed up, I’m posting them below.
Calpont’s InfiniDB
Since its inception, Calpont has gone through multiple management teams, strategies, and investor groups. What it hadn’t done, ever, is actually shipped a product. Last week, however, Calpont introduced a free/open source DBMS, InfiniDB, with technical details somewhat reminiscent of what Calpont was promising last April. Highlights include:
- Like Infobright, Calpont’s InfiniDB is a columnar DBMS consisting of a MySQL front end and a columnar storage engine.
- Community edition InfiniDB runs on a single server.
- One of commercial/enterprise edition InfiniDB’s main claims to fame will be MPP support.
- There’s no announced time frame for commercial edition InfiniDB.
- InfiniDB’s current compression story is dictionary/token only, with decompression occurring before joins are executed. Improvement is a roadmap item.
- Indeed, InfiniDB has many roadmap items, a few of which can be found here. Also, a great overview of InfiniDB’s current state and roadmap can be found in this MySQL Performance Blog thread. (And follow the links there to find performance discussions of other free analytic DBMS.)
- One thing InfiniDB already has that is still a roadmap item for Infobright is the ability to run a query across multiple cores at once.
- One thing free InfiniDB has that Infobright only offers in its Enterprise Edition is ACID-compliant Insert/Update/Delete. (Note: I wish people would stop saying that Infobright Enterprise Edition isn’t ACID-compliant, since that point was cleared up a while ago.)
- InfiniDB has no indexes or materialized views.
- However, InfiniDB’s retrieval is expedited by something called “Extents,” which sounds a lot like Netezza’s zone maps.
Being on vacation, I’ll stop there for now. (If it weren’t for Tropical Storm/ depression Ida, I might not even be posting this much until I get back.)
| Categories: Analytic technologies, Calpont, Columnar database management, Data warehousing, Database compression, Infobright, MySQL, Open source | 3 Comments |
Aster Data 4.0 and the evolution of “advanced analytic(s) servers”
Since Linda and I are leaving on vacation in a few hours, Aster Data graciously gave me permission to morph its “12:01 am Monday, November 2” embargo into “late Friday night.”
Aster Data is officially announcing the 4.0 release of nCluster. There are two big pieces to this announcement:
- Aster is offering a slick vision for integrating big-database management and general analytic processing on the same MPP cluster, under the not-so-slick name “Data-Application Server.”
- Aster is also offering a sophisticated vision for workload management.
In addition, Aster has matured nCluster in various ways, for example cleaning up a performance problem with single-row updates.
Highlights of the Aster “Data-Application Server” story include: Read more
| Categories: Aster Data, Cloud computing, Data warehousing, EAI, EII, ETL, ELT, ETLT, MapReduce, Market share and customer counts, Teradata, Theory and architecture, Workload management | 9 Comments |
A question on MDX performance
An enterprise user wrote in with a question that boils down to:
What are reasonable MDX performance expectations?
MDX doesn’t come up in my life very much, and I don’t have much intuition about it. E.g., I don’t know whether one can slap an MDX-to-SQL converter on top of a fast analytic RDBMS and go to town. What’s more, I’m heading off on vacation and don’t feel like researching the matter myself in the immediate future. 🙂
So here’s the long form of the question. Any thoughts?
I have a general question on assessing the performance of an OLAP technology using a set of MDX queries. I would be interested to know if there are any benchmark MDX performance tests/results comparing different OLAP technologies (which may be based on different underlying DBMS’s if appropriate) on similar hardware setup, or even comparisons of complete appliance solutions. More generally, I want to determine what performance limits I could reasonably expect on what I think are fairly standard servers.
In my own work, I have set up a star schema model centered on a Fact table of 100 million rows (approx 60 columns), with dimensions ranging in cardinality from 5 to 10,000. In ad hoc analytics, is it expected that any query against such a dataset should return a result within a minute or two (i.e. before a user gets impatient), regardless of whether that query returns 100 cells or 50,000 cells (without relying on any aggregate table or caching mechanism)? Or is that level of performance only expected with a high end massively parallel software/hardware solution? The server specs I’m testing with are: 32-bit 4 core, 4GB RAM, 7.2k RPM SATA drive, running Windows Server 2003; 64-bit 8 core, 32GB RAM, 3 Gb/s SAS drive, running Windows Server 2003 (x64).
I realise that caching of query results and pre-aggregation mechanisms can significantly improve performance, but I’m coming from the viewpoint that in purely exploratory analytics, it is not possible to have all combinations of dimensions calculated in advance, in addition to being maintained.
| Categories: Analytic technologies, Benchmarks and POCs, Data warehousing, MOLAP | 16 Comments |
Teradata’s nebulous cloud strategy
As the pun goes, Teradata’s cloud strategy is – well, it’s somewhat nebulous. More precisely, for the foreseeable future, Teradata’s cloud strategy is a collection of rather disjointed parts, including:
- What Teradata calls the Teradata Agile Analytics Cloud, which is a combination of previously existing technology plus one new portlet called the Teradata Elastic Mart(s) Builder. (Teradata’s Elastic Mart(s) Builder Viewpoint portlet is available for download from Teradata’s Developer Exchange.)
- Teradata Data Mover 2.0, coming “Soon”, which will ease copying (ETL without any significant “T”) from one Teradata system to another.
- Teradata Express DBMS crippleware (1 terabyte only, no production use), now available on Amazon EC2 and VMware. (I don’t see where this has much connection to the rest of Teradata’s cloud strategy, except insofar as it serves to fill out a slide.)
- Unannounced (and so far as I can tell largely undesigned) future products.
Teradata openly admits that its direction is heavily influenced by Oliver Ratzesberger at eBay. Like Teradata, Oliver and eBay favor virtual data marts over physical ones. That is, Oliver and eBay believe that the ideal scenario is that every piece of data is only stored once, in an integrated Teradata warehouse. But eBay believes and Teradata increasingly agrees that users need a great deal of control over their use of this data, including the ability to import additional data into private sandboxes, and join it to the warehouse data already there. Read more
| Categories: Analytic technologies, Cloud computing, Data integration and middleware, Data warehousing, EAI, EII, ETL, ELT, ETLT, eBay, Teradata, Theory and architecture | 5 Comments |
Teradata hardware strategy and tactics
In my opinion, the most important takeaways about Teradata’s hardware strategy from the Teradata Partners conference last week are:
- Teradata’s future lies in solid-state memory. That’s in line with what Carson Schmidt told me six months ago.
- To Teradata’s surprise, the solid-state future is imminent. Teradata is 6-9 months further along with solid-state drives (SSD) than it thought a year ago it would be at this point.
- Short-term, Teradata is going to increase the number of appliance kinds it sells. I didn’t actually get details on anything but the new SSD-based Blurr, but it seems there will be others as well.
- Teradata’s eventual future is to mix and match parts (especially different kinds of storage) in a more modular product line. Teradata Virtual Storage is of pretty limited value otherwise. I probably believe Teradata will go modular more emphatically than Teradata itself does, because I think doing so will meet users needs more effectively than if Teradata relies strictly on fixed appliance configurations.
In addition, some non-SSD componentry tidbits from Carson Schmidt include:
- Teradata really likes Intel’s Nehalem CPUs, with special reference to multi-threading, QuickPath interconnect, and integrated memory controller. Obviously, Nehalem-based Teradata boxes should be expected in the not too distant future.
- Teradata really likes Nehalem’s successor Westmere too, and expects to be pretty fast to market with it (faster than with Nehalem) because Nehalem and Westmere are plug-compatible in motherboards.
- Teradata will go to 10-gigabit Ethernet for external connectivity on all its equipment, which should improve load performance.
- Teradata will also go to 10-gigabit Ethernet to play the Bynet role on appliances. Tests are indicating this improves query performance.
- What’s more, Teradata believes there will be no practical scale-out limitations with 10-gigabit Ethernet.
- Teradata hasn’t decided yet what to do about 2.5” SFF (Small Form Factor) disk drives, but is leaning favorably. Benefits would include lower power consumption and smaller cabinets.
- Also on Carson’s list of “exciting” future technologies is SAS 2.0, which at 6 gigabits/second doubles the I/O bandwidth of SAS 1.0.
- Carson is even excited about removing universal power supplies from the cabinets, increasing space for other components.
- Teradata picked Intel’s Host Bus Adapters for 10-gigabit Ethernet. The switch supplier hasn’t been determined yet.
Let’s get back now to SSDs, because over the next few years they’re the potential game-changer. Read more
| Categories: Data warehouse appliances, Data warehousing, Solid-state memory, Storage, Teradata | 13 Comments |
Reports of perfectly-balanced hardware configurations are greatly exaggerated
Data warehouse appliance and software appliance vendors like to claim that they’ve worked out just the right hardware configuration(s), and that a single configuration is correct for a fairly broad range of workloads. But there are a lot of reasons to be dubious about that. Specific vendor evidence includes:
- Teradata ascribes considerable importance to a Virtual Storage technology whose main purpose is to allow mixing of heterogeneous storage devices in a single system. And the discussion rarely suggests that these parts will be in a rigid fixed relationship.
- Netezza — as Teradata keeps reminding me — often sells boxes with the expectation that they won’t be filled with data, so as to increase spindle count and hence performance.
- Oracle/Sun have dropped some comments about Exadata being more flexibly configured going forward.
- Kickfire’s new “high-end” appliance lets you attach fairly arbitrary amounts of external storage.
- And of course, software-only analytic DBMS vendors run their software in all sorts of hardware and storage environments.
What’s more, the claim never made a lot of sense anyway. With the rarest of exceptions, even a single data warehouse’s workload will contain different queries that strain different parts of the system in different ratios. Calculating the “ideal” hardware configuration for that single workload would be forbiddingly difficult. And even if one could calculate it, it almost surely would be different than another user’s “ideal” configuration. How a single hardware configuration can be “ideally balanced” for a broad class of use cases boggles the imagination.
| Categories: Data warehouse appliances, Data warehousing, Exadata, Kickfire, Netezza, Oracle, Teradata | 6 Comments |
Greenplum Single-Node Edition — sometimes free is a real cool price
Greenplum is announcing today that you can run Greenplum software on a single 8-core commodity server, free. First and foremost, that’s a strong statement that Greenplum wants enterprises to pay it for Greenplum’s parallelization/”private cloud” capabilities. Second, it may be an attractive gift to a variety of folks who want to extract insight from terabyte-scale databases of various kinds.
Greenplum Single-Node Edition:
- Is free of charge, although you can buy support.
- Has no restrictions on use, production or otherwise.
- Has no restrictions on database size.
- Is closed-source.
For those who want free, terabyte-scale data warehousing software, Greenplum Single-Node Edition may be quite appealing, considering that the main available alternatives are:
- General-purpose open-source DBMS, such as PostgreSQL and MySQL (lacking analytic DBMS performance and features)
- Infobright Community Edition (the other best choice – Infobright’s commercial sales success indicates the solidity of Infobright’s technology)
- Rough research-project code and other other questionable open source offerings
- Crippleware from other commercial analytic DBMS vendors (e.g., Teradata)
For example, comparing PostgreSQL-based Greenplum with PostgreSQL itself, Greenplum offers:
- The ability to scale out queries across all cores in your box (and no, pgpool is not a serious alternative)
- Storage alternatives such as columnar (I am told that EnterpriseDB recently stopped funding a project for a PostgreSQL columnar option)
| Categories: Analytic technologies, Data warehousing, EnterpriseDB and Postgres Plus, Greenplum, Infobright, Open source, PostgreSQL, Pricing, Scientific research | 14 Comments |
This week at the Teradata Partners user conference
Teradata tells me that its press embargoes are ending at 9:00 this morning. Here are some highlights of what’s going on, although names, dates, and details will have to await conversations and press releases this week.
- Teradata is productizing “private cloud,” under names including “Teradata Enterprise Analytics Cloud,” “Teradata Agile Analytics Cloud,” and “Teradata Elastic Mart Builder.” I.e., Teradata hopes to leapfrog Greenplum in its “Enterprise Data Cloud” strategy. This is only fair, in that Greenplum lifted the idea from Teradata and eBay in the first place. It also provides major support for what I think is an extremely sensible trend. Give or take issues of who announces and ships what a couple months before or after a competitor, my early thinking is that the main differences between Greenplum and Teradata in this regard will be:
- Virtual as opposed to just physical data marts, based on robust workload management software. (Advantage: Teradata)
- Pricing, deployment options. (Advantage: Greenplum)
- Features that don’t directly relate to enterprise/private cloud. (Advantage: Either, often Teradata.)
- Teradata is generally strengthening its data movement technology, e.g. for making various appliances work in sync. I’m not too clear yet on the details of that. I think this is what Teradata’s phrase “ecosystem management” refers to.
- Teradata is (pre-)announcing – at least as a statement of direction — an appliance based on solid-state drives (SSDs). I’ve thought for a while that Teradata was a leader in thinking through the issues around solid-state memory in data warehousing, so it makes sense that they’re among the leaders in actually coming to market as well. I plan to say more after meeting with, e.g., Carson Schmidt.
- Teradata has achieved a 300%ish speed-up in geospatial processing. I gather this is largely a byproduct of the parallel analytics work Teradata did around strengthening its SAS integration. However, there don’t seem to be a lot of Teradata geospatial users yet.
- Teradata Express, Teradata’s free Windows-based crippleware, is being ported to Amazon EC2 and VMware as well. Presumably to avoid cannibalizing Teradata product sales, there are quite a few limitations on Teradata Express, including system capacity, database size, and “no production use.”
- Teradata continues to extend its optimizations to handle queries issued by business intelligence tools. Previously, the focus of what Teradata discussed in this regard was query rewrite. But soon automatic recommendation and creation of Aggregate Join Indexes – i.e.., materialized views – will be included as well.
Greenplum customer notes
In a briefing about a forthcoming product announcement, Greenplum threw in a slide saying:
- Greenplum is getting 12-15 new (paying) customers per quarter, all of whom it fondly refers to as “Tier 1” enterprises.
- Greenplum will hit the 100+ customer mark this quarter (thus joining Vertica and Infobright).
- <10% of Greenplum business is now “influenced” by Sun hardware.
I asked Ben Werther to unpack that last claim for me. He quickly noted that it wasn’t his slide, but rather had been put together by colleagues. That said:
- As of the past quarter or two, <10% of Greenplum’s sales activity is on Sun, which works out to maybe one sale per quarter and at most a small number of sales cycles. (That’s down from from 50%+ not that long ago.)
- Most Greenplum business is now on HP or Dell equipment. Some is on IBM. There are some interesting sales cycles on Cisco’s new UCS (Unified Computing System) blades, but no closed deals yet. EMC seems to be part of the Cisco story.
No doubt part of the reason for the move away from Sun equipment is the impending Oracle acquisition. Another may be that the Greenplum/Sun appliance is somewhat underpowered. E.g., without particularly high levels of compression, eBay puts over 60 terabytes of data on each Greenplum node, which probably isn’t ideal from the standpoint of query performance.
Greenplum also says that 50% or so of sales are subscription-priced, rather than perpetual-licensed. I don’t have a sense for how long that’s been going on. (Edit: Ben Werther tells me this has been true for over a year.)