EAI, EII, ETL, ELT, ETLT
Analysis of data integration products and technologies, especially ones related to data warehousing, such as ELT (Extract/Transform/Load). Related subjects include:
In today’s post about HCatalog, I noted that the Hadoop/HCatalog community didn’t necessarily understand all the kinds of metadata that enterprises need and want, especially in the context of data integration and ETL and ELT (Extract/Transform/Load/Transform). That raises a natural question — what kinds of metadata do users need or want? In the hope of spurring discussion, from vendors and users alike, I’m splitting this question out into a separate post.
Please comment with your thoughts about ETL-related metadata needs. The conversation needs to advance.
In the relational world, there are at least three kinds of metadata:
- Definitional information about data structures, without which you can’t have a relational database at all. That area seems binary; either you have enough to make sense of your data or you don’t.
- Statistics about columns and tables, such as the most frequent values and how often they occur, which are kept for the purpose of optimization. Those seem to be nice-to-haves more than must-haves. The more information of this kind you have, the more chances you have to save resources.
- Historical and security information about data. This is where things get really complicated. It’s also where Hadoop is still in the “So what exactly should we build?” stage of design.
As I see it:
- Historical information about data answers questions in the realm of “Who did what to which data when?”
- Security information about data answers questions around “Who may do what to which data in the future?”
- They overlap because:
- They rely on closely related schemes for assessing roles and identity.
- Audit trails, a key aspect of security and compliance, could logically be viewed as falling in the realm of “history”.
Vertica 6 was recently announced, and so it seemed like a good time to catch up on Vertica features. The main topics I want to address are:
- External tables and the associated new Hadoop connector.
- Online schema evolution.
- Workload management.
- I have some tidbits to add to my June, 2011 coverage of Vertica’s analytic functionality.
- I’ll stand for now on my previous coverage of Vertica’s database organization.
In general, the main themes of Vertica 6 appear to be:
- Enterprise/SaaS-friendliness, high uptime, and so on.
- Improved analytic usefulness.
Let’s do the analytic functionality first. Notes on that include:
- Vertica has extended its user-defined function/analytic procedure/whatever functionality to include user-defined load. (Same SDK, different specific classes.)
- One of the languages Vertica supports is R. But for now, parallel R is limited to “Of course, you can run the same functions and procedures on many nodes at once.”
- Based on community activity around bugs and so on, it seems there are users for Vertica’s JSON-based Twitter sentiment analysis plug-in.
I’ll also take this opportunity to expand on something I wrote about a few vendors — including Vertica — at the end of my post on approximate query results. When I probed how customers of Vertica and other RDBMS-based analytic platform vendors used vendor-proprietary advanced analytic SQL and other analytic capabilities, answers included: Read more
|Categories: Columnar database management, Data warehousing, EAI, EII, ETL, ELT, ETLT, Hadoop, Investment research and trading, Predictive modeling and advanced analytics, SQL/Hadoop integration, Vertica Systems, Workload management||1 Comment|
In a short October, 2011 post about Datameer, I wrote:
Datameer is designed to let you do simple stuff on large amounts of data, where “large amounts of data” typically means data in Hadoop, and “simple stuff” includes basic versions of a spreadsheet, of BI, and of EtL (Extract/Transform/Load, without much in the way of T).
That’s all still mainly true, although with the recent Datameer 2.0:
- You can run Datameer and the underlying Hadoop on a desktop or workgroup group.
- There are some infographics pretty-picture-drawing capabilities, which will surely delight those who like vector-based HTML 5 pictures of coffee cups, saucers and macaroons.
- No doubt Datameer has been generally enhanced on multiple fronts.
In essence, Datameer has two positionings.
- One is “OK, you’ve got Hadoop — now wouldn’t you like to do something useful with it?” That can include both business intelligence and ETL.
- Beyond that, Datameer founder/CEO Stefan Groschupf’s core argument is that schema-on-read is really, really useful, even at the cost of absorbing a potentially large performance hit. In other words, he’s making a case for a form of non-relational BI.
|Categories: Business intelligence, Data models and architecture, Datameer, EAI, EII, ETL, ELT, ETLT, Hadoop, Log analysis, Market share and customer counts, Web analytics||7 Comments|
From time to time, I try to step back and build a little taxonomy for the variety in database technology. One effort was 4 1/2 years ago, in a pre-planned exchange with Mike Stonebraker (his side, alas, has since been taken down). A year ago I spelled out eight kinds of analytic database.
The angle I’ll take this time is to say that every sufficiently large enterprise needs to be cognizant of at least 7 kinds of database challenge. General notes on that include:
- I’m using the weasel words “database challenge” to evade questions as to what is or isn’t exactly a DBMS.
- One “challenge” can call for multiple products and technologies even within a single enterprise, let alone at different ones. For example, in this post the “eight kinds of analytic database” are reduced to just a single category.
- Even so, one product or technology may be well-suited to address a couple different kinds of challenges.
The Big Seven database challenges that almost any enterprise faces are: Read more
|Categories: Data integration and middleware, Data models and architecture, Database diversity, EAI, EII, ETL, ELT, ETLT, Hadoop, Memory-centric data management, NoSQL, Object, OLTP, RDF and graphs, Structured documents, Talend, Text||3 Comments|
When I grumbled about the conference-related rush of Hadoop announcements, one example of many was Teradata Aster’s SQL-H. Still, it’s an interesting idea, and a good hook for my first shot at writing about HCatalog. Indeed, other than the Talend integration bundled into Hortonworks’ HDP 1, Teradata SQL-H is the first real use of HCatalog I’m aware of.
The Teradata SQL-H idea is:
- Register your Hadoop data to HCatalog. I’ll confess to being unclear about the details of how that works, for example in the case of data that just doesn’t fit well into flat relational tables. Stay tuned for future posts. For now, I’ll just note that:
- HCatalog is closely based on Hive’s metadata management. If you’ve run Hive against the data, HCatalog should already know about it.
- HCatalog can handle Pig and HBase data as well.
- Write SQL DDL (Data Description Language) so that your Aster cluster knows about the data.
- Write any Teradata Aster SQL/MR against that data. Some of the execution will be done on the Hadoop cluster, but pulling data back into Aster may well be necessary.
At least in theory, Teradata SQL-H lets you use a full set of analytic tools against your Hadoop data, with little limitation except price and/or performance. Teradata thinks the performance of all this can be much better than if you just use Hadoop (35X was mentioned in one particularly favorable example), but perhaps much worse than if you just copy/extract the data to an Aster cluster in the first place.
So what might the use cases be for something like SQL-H? Offhand, I’d say:
- SQL-H use cases are probably focused in areas where copying the data to Aster in advance doesn’t make a lot of sense. So presumably …
- … the Hadoop clusters involved would hold a lot more data than you’d want to pay for storing in Teradata Aster. E.g., think of cases where Hadoop is used as a big bit bucket or archival data store.
- There could be a kind of investigative workflow. First you play around with the Hadoop data via SQL-H. Then when you think you’re onto something, you set up ETL (Extract/Transform/Load) to get the data into Aster and ratchet up the effort.
By way of contrast, the whole thing makes less sense for dashboarding kinds of uses, unless the dashboard users are very patient when they want to drill down.
|Categories: Aster Data, Data integration and middleware, Data warehousing, EAI, EII, ETL, ELT, ETLT, Emulation, transparency, portability, Hadoop, MapReduce, SQL/Hadoop integration, Teradata||10 Comments|
In my recent series of Hadoop posts, there were several cases where I had to choose between recommending that enterprises:
- Go with the most advanced features any vendor was credibly advocating.
- Be more cautious, and only adopt features that have been solidly proven in the field.
I favored the more advanced features each time. Here’s why.
To a first approximation, I divide Hadoop use cases into two major buckets, only one of which I was addressing with my comments:
1. Analytic data management.* Here I favored features over reliability because they are more important, for Hadoop as for analytic RDBMS before it. When somebody complains about an analytic data store not being ready for prime time, never really working, or causing them to tear their hair out, what they usually mean is that:
- It couldn’t do the work that needed doing …
- … with reasonable performance and turnaround time …
- … without undue effort in administration and/or programming.
Those complaints are much, much, more frequent than “It crashed”. So it was for Netezza, DATAllegro, Greenplum, Aster Data, Vertica, Infobright, et al. So it also is for Hadoop. And how does one address those complaints? By performance and feature enhancements, of the kind that the Hadoop community is introducing at high speed. Read more
|Categories: Buying processes, Data warehousing, EAI, EII, ETL, ELT, ETLT, Hadoop, HBase, Hortonworks, Open source||Leave a Comment|
This is part of a three-post series:
The canonical Metamarkets batch ingest pipeline is a bit complicated.
- Data lands on Amazon S3 (uploaded or because it was there all along).
- Metamarkets processes it, primarily via Hadoop and Pig, to summarize and denormalize it, and then puts it back into S3.
- Metamarkets then pulls the data into Hadoop a second time, to get it ready to be put into Druid.
- Druid is notified, and pulls the data from Hadoop at its convenience.
By “get data read to be put into Druid” I mean:
- Build the data segments (recall that Druid manages data in rather large segments).
- Note metadata about the segments.
That metadata is what goes into the MySQL database, which also retains data about shards that have been invalidated. (That part is needed because of the MVCC.)
By “build the data segments” I mean:
- Make the sharding decisions.
- Arrange data columnarly within shard.
- Build a compressed bitmap for each shard.
When things are being done that way, Druid may be regarded as comprising three kinds of servers: Read more
In August 2010, I wrote about Workday’s interesting technical architecture, highlights of which included:
- Lots of small Java objects in memory.
- A very simple MySQL backing store (append-only, <10 tables).
- Some modernistic approaches to application navigation.
- A faceted approach to BI.
I caught up with Workday recently, and things have naturally evolved. Most of what we talked about (by my choice) dealt with data management, business intelligence, and the overlap between the two.
It is now reasonable to say that Workday’s servers fall into at least seven tiers, although we talked mainly about five that work together as a kind of giant app/database server amalgamation. The three that do noteworthy data management can be described as:
- In-memory objects and transactions. This is similar to what Workday had before.
- Persistent MySQL. Part of this is similar to what Workday had before. In addition, Workday is now storing certain data in tables in the ordinary relational way.
- In-memory caching and indexing. This has three aspects:
- Indexes for the ordinary relational tables, organized in interesting ways.
- Indexes for Workday’s search-box navigation (as per my original Workday technical post, you can search across objects, task-names, etc.).
- Compressed copies of the Java objects, used to instantiate other servers as needed. The most obvious uses of this are:
- Recovery for the object/transaction tier.
- Launch for the elastic compute tier. (Described below.)
Two other Workday server tiers may be described as: Read more
QlikTech has bought Expressor. Notes on that include:
- Expressor wanted to offer data integration/ETL (Extract/Transform/Load) that was all things to all people — great parallel performance, great UI, great price, etc.
- In practice, Expressor seemed to focus on cheap/easy ETL in the Microsoft Windows (I mean server) market.
- Expressor never got much traction. This seems confirmed by the “more than 20″ figure for headcount mentioned in the acquisition press release.
- Both the press release and some tweets by QlikTech’s Donald Farmer seem to confirm that Expressor is being taken off the market for “boil the ocean” ETL. It will be companion technology to/integrated technology in QlikView.
- Unsurprisingly, Donald indicated that Expressor technology would expand past its Microsoft focus. (Edit: “If needed”)
|Categories: Business intelligence, EAI, EII, ETL, ELT, ETLT, Expressor, Pricing, QlikTech and QlikView||5 Comments|
I first became an analyst in 1981. And so I was around for the early days of the movement from batch to interactive computing, as exemplified by:
- The rise of minicomputers as mainframe alternatives (first VAXen, then the ‘nix systems that did largely supplant mainframes).
- The move from batch to interactive computing even on mainframes, a key theme of 1980s application software industry competition.
Of course, wherever there is interactive computing, there is a desire for interaction so fast that users don’t notice any wait time. Dan Fylstra, when he was pitching me the early windowing system VisiOn, characterized this as response so fast that the user didn’t tap his fingers waiting.* And so, with the move to any kind of interactive computing at all came a desire that the interaction be quick-response/low-latency. Read more