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:
Greenplum is in the big leagues
After a March, 2007 call, I didn’t talk again with Greenplum until earlier this month. That changed fast. I flew out to see Greenplum last week and spent over a day with president/co-founder Scott Yara, CTO/co-founder Luke Lonergan, marketing VP Paul Salazar, and product management/marketing director Ben Werther. Highlights – besides some really great sushi at Sakae in Burlingame – start with an eye-opening set of customer proof points, such as: Read more
| Categories: Analytic technologies, Data warehouse appliances, Data warehousing, Greenplum, Petabyte-scale data management, PostgreSQL | 19 Comments |
My current customer list among the data warehouse specialists
One of my favorite pages on the Monash Research website is the list of many current and a few notable past customers. (Another favorite page is the one for testimonials.) For a variety of reasons, I won’t undertake to be more precise about my current customer list than that. But I don’t think it would hurt anything to list the data warehouse DBMS/appliance specialists in the group. They are:
- Aster Data
- Calpont
- DATAllegro
- Greenplum
- Infobright
- Netezza
- ParAccel
- Teradata
- Vertica
All of those are Monash Advantage members.
If you care about all this, you may also be interested in the rest of my standards and disclosures.
| Categories: About this blog, Aster Data, Calpont, Data warehousing, DATAllegro, Greenplum, Infobright, Netezza, ParAccel, Teradata, Vertica Systems | 3 Comments |
Kevin Closson doesn’t like MPP
Kevin Closson of Oracle offers a long criticism of the popularity of MPP. Key takeaways include:
- TPC-H benchmarks that show Oracle as somewhat superior to DB2 are highly significant.
- TPC-H benchmarks in which MPP vendors destroy Oracle are too unimportant to even mention.
- SMP did better than MPP the last time he was in a position to judge (which evidently was some time during the Clinton Administration), so it surely must still be superior for all purposes today.
| Categories: Data warehousing, Oracle, Parallelization | 20 Comments |
Three happy 100 terabyte-plus customers for DATAllegro
Over on my Network World blog, I asked the question “So who are DATAllegro’s actual current customers?” As regular readers know, that’s a fairly hard question to answer. TEOCO is widely known as DATAllegro’s flagship reference, but after that the list gets thin in a hurry.
As a by-the-by to other discussions, DATAllegro Stuart Frost undertook to respond in part himself. Specifically, he gave me two names of two other happy customers that are or imminently will be running DATAllegro against 100+ terabytes of user data. Read more
| Categories: Data warehouse appliances, Data warehousing, DATAllegro, DBMS product categories | Leave a Comment |
Exasol technical briefing
It took 5 ½ months after my non-technical introduction, but I finally got a briefing from Exasol’s technical folks (specifically, the very helpful Mathias Golombek and Carsten Weidmann). Here are some highlights: Read more
| Categories: Analytic technologies, Benchmarks and POCs, Columnar database management, Data warehousing, Exasol, In-memory DBMS, Memory-centric data management, Pricing | 1 Comment |
Patent nonsense in the data warehouse DBMS market
There are two recent patent lawsuits in the data warehouse DBMS market. In one, Sybase is suing Vertica. In another, an individual named Cary Jardin (techie founder of XPrime, a sort of predecessor company to ParAccel) is suing DATAllegro. Naturally, there’s press coverage of the DATAllegro case, due in part to its surely non-coincidental timing right after the Microsoft acquisition was announced and in part to a vigorous PR campaign around it. And the Sybase case so excited a troll who calls himself Bill Walters that he posted identical references to it on about 12 different threads in this blog, as well as to a variety of Vertica-related articles in the online trade press. But I think it’s very unlikely that any of these cases turn out to much matter. Read more
| Categories: Columnar database management, Data warehousing, Database compression, DATAllegro, Sybase, Vertica Systems | 7 Comments |
Compare/constrast of Vertica, ParAccel, and Exasol
I talked with Exasol today – at 5:00 am! — and of course want to blog about it. For clarity, I’d like to start by comparing/contrasting the fundamental data structures at Vertica, ParAccel, and Exasol. And it feels like that should be a separate post. So here goes.
- Exasol, Vertica, and ParAccel all store data in columnar formats.
- Exasol, Vertica, and ParAccel all compress data heavily.
- Exasol and Vertica operate on in-memory data in compressed formats. ParAccel decompresses the data when it gets to RAM. Exasol, Vertica, and ParAccel all — perhaps to varying extents — operate on in-memory data in compressed formats.
- ParAccel and Exasol write data to what amounts to the in-memory part of their basic data structures; the data then gets persisted to disk. Vertica, however, has a separate in-memory data structure to accept data and write it to disk.
- Vertica is a disk-centric system that doesn’t rely on there being a lot of RAM.
- ParAccel can be described that way too; however, in some cases (including on the TPC-H benchmarks), ParAccel recommends loading all your data into RAM for maximum performance.
- Exasol is totally optimized for the assumption that queries will be run against data that had already been previously loaded into RAM.
Beyond the above, I plan to discuss in a separate post how Exasol does MPP shared-nothing software-only columnar data warehouse database management differently than Vertica and ParAccel do shared-nothing software-only columnar data warehouse database management. 🙂
| Categories: Columnar database management, Data warehousing, Database compression, Exasol, ParAccel, Vertica Systems | 12 Comments |
Netezza update
In my usual dual role, I called Phil Francisco of Netezza to lay some post-Microsoft/DATAllegro consulting on him late on a Friday night — and then took the opportunity of being on the phone with him to get a general Netezza update. Netezza’s July quarter just ended, so they’re still in quiet period, so I didn’t press him for a lot of numerical detail. More generally, I didn’t find a lot out that wasn’t already covered in my May Netezza update. But notwithstanding all those disclaimers, it was still a pretty interesting chat. Read more
| Categories: Data warehouse appliances, Data warehousing, Greenplum, Netezza, Sybase | 3 Comments |
Database compression coming to the fore
I’ve posted extensively about data-warehouse-focused DBMS’ compression, which can be a major part of their value proposition. Most notable, perhaps, is a short paper Mike Stonebraker wrote for this blog — before he and his fellow researchers started their own blog — on column-stores’ advantages in compression over row stores. Compression has long been a big part of the DATAllegro story, while Netezza got into the compression game just recently. Part of Teradata’s pricing disadvantage may stem from weak compression results. And so on.
Well, the general-purpose DBMS vendors are working busily at compression too. Microsoft SQL Server 2008 exploits compression in several ways (basic data storage, replication/log shipping, backup). And Oracle offers compression too, as per this extensive writeup by Don Burleson.
If I had to sum up what we do and don’t know about database compression, I guess I’d start with this:
- Columnar DBMS really do get substantially better compression than row-based database systems. The most likely reasons are:
- More elements of a column fit into a single block, so all compression schemes work better.
- More compression schemes wind up getting used (e.g., delta compression as well the token/dictionary compression that row-based systems use too).
- Data-warehouse-based row stores seem to do better at compression than general-purpose DBMS. The reasons most likely are some combination of:
- They’re trying harder.
- They use larger block sizes.
- Notwithstanding these reasonable-sounding generalities, there’s a lot of variation in compression success among otherwise comparable products.
Compression is one of the most important features a database management system can have, since it creates large savings in storage and sometimes non-trivial gains in performance as well. Hence, it should be a key item in any DBMS purchase decision.
Column stores vs. vertically-partitioned row stores
Daniel Abadi and Sam Madden followed up their post on column stores vs. fully-indexed row stores with one about column stores vs. vertically-partitioned row stores. Once again, the apparently reasonable way to set up the row-store database backfired badly.* Read more