DBMS product categories
Analysis of database management technology in specific product categories. Related subjects include:
- Kafka has gotten considerable attention and adoption in streaming.
- Kafka is open source, out of LinkedIn.
- Folks who built it there, led by Jay Kreps, now have a company called Confluent.
- Confluent seems to be pursuing a fairly standard open source business model around Kafka.
- Confluent seems to be in the low to mid teens in paying customers.
- Confluent believes 1000s of Kafka clusters are in production.
- Confluent reports 40 employees and $31 million raised.
At its core Kafka is very simple:
- Kafka accepts streams of data in substantially any format, and then streams the data back out, potentially in a highly parallel way.
- Any producer or consumer of data can connect to Kafka, via what can reasonably be called a publish/subscribe model.
- Kafka handles various issues of scaling, load balancing, fault tolerance and so on.
So it seems fair to say:
- Kafka offers the benefits of hub vs. point-to-point connectivity.
- Kafka acts like a kind of switch, in the telecom sense. (However, this is probably not a very useful metaphor in practice.)
|Categories: Complex event processing (CEP), Data integration and middleware, Humor, Kafka and Confluent, Market share and customer counts, Microsoft and SQL*Server, Open source, Specific users||9 Comments|
Mike Stonebraker and Larry Ellison have numerous things in common. If nothing else:
- They’re both titanic figures in the database industry.
- They both gave me testimonials on the home page of my business website.
- They both have been known to use the present tense when the future tense would be more accurate.
I mention the latter because there’s a new edition of Readings in Database Systems, aka the Red Book, available online, courtesy of Mike, Joe Hellerstein and Peter Bailis. Besides the recommended-reading academic papers themselves, there are 12 survey articles by the editors, and an occasional response where, for example, editors disagree. Whether or not one chooses to tackle the papers themselves — and I in fact have not dived into them — the commentary is of great interest.
But I would not take every word as the gospel truth, especially when academics describe what they see as commercial market realities. In particular, as per my quip in the first paragraph, the data warehouse market has not yet gone to the extremes that Mike suggests,* if indeed it ever will. And while Joe is close to correct when he says that the company Essbase was acquired by Oracle, what actually happened is that Arbor Software, which made Essbase, merged with Hyperion Software, and the latter was eventually indeed bought by the giant of Redwood Shores.**
*When it comes to data warehouse market assessment, Mike seems to often be ahead of the trend.
**Let me interrupt my tweaking of very smart people to confess that my own commentary on the Oracle/Hyperion deal was not, in retrospect, especially prescient.
Mike pretty much opened the discussion with a blistering attack against hierarchical data models such as JSON or XML. To a first approximation, his views might be summarized as: Read more
- I’ve suggested in the past that multi-data-center capabilities are important for “data sovereignty”/geo-compliance.
- The need for geo-compliance just got a lot stronger, with the abolition of the European Union’s Safe Harbour rule for the US. If you collect data in multiple countries, you should be at least thinking about geo-compliance.
- Cassandra is an established leader in multi-data-center operation.
But when I made that connection and checked in accordingly with my client Patrick McFadin at DataStax, I discovered that I’d been a little confused about how multi-data-center Cassandra works. The basic idea holds water, but the details are not quite what I was envisioning.
The story starts:
- Cassandra groups nodes into logical “data centers” (i.e. token rings).
- As a best practice, each physical data center can contain one or more logical data center, but not vice-versa.
- There are two levels of replication — within a single logical data center, and between logical data centers.
- Replication within a single data center is planned in the usual way, with the principal data center holding a database likely to have a replication factor of 3.
- However, copies of the database held elsewhere may have different replication factors …
- … and can indeed have different replication factors for different parts of the database.
In particular, a remote replication factor for Cassandra can = 0. When that happens, then you have data sitting in one geographical location that is absent from another geographical location; i.e., you can be in compliance with laws forbidding the export of certain data. To be clear (and this contradicts what I previously believed and hence also implied in this blog):
- General multi-data-center operation is not what gives you geo-compliance, because the default case is that the whole database is replicated to each data center.
- Instead, you get that effect by tweaking your specific replication settings.
|Categories: Cassandra, Clustering, DataStax, HBase, NoSQL, Open source, Specific users, Surveillance and privacy||3 Comments|
I last wrote about Couchbase in November, 2012, around the time of Couchbase 2.0. One of the many new features I mentioned then was secondary indexing. Ravi Mayuram just checked in to tell me about Couchbase 4.0. One of the important new features he mentioned was what I think he said was Couchbase’s “first version” of secondary indexing. Obviously, I’m confused.
Now that you’re duly warned, let me remind you of aspects of Couchbase timeline.
- 2 corporate name changes ago, Couchbase was organized to commercialize memcached. memcached, of course, was internet companies’ default way to scale out short-request processing before the rise of NoSQL, typically backed by manually sharded MySQL.
- Couchbase’s original value proposition, under the name Membase, was to provide persistence and of course support for memcached. This later grew into a caching-oriented pitch even to customers who weren’t already memcached users.
- A merger with the makers of CouchDB ensued, with the intention of replacing Membase’s SQLite back end with CouchDB at the same time as JSON support was introduced. This went badly.
- By now, however, Couchbase sells for more than distributed cache use cases. Ravi rattled off a variety of big-name customer examples for system-of-record kinds of use cases, especially in session logging (duh) and also in travel reservations.
- Couchbase 4.0 has been in beta for a few months.
Technical notes on Couchbase 4.0 — and related riffs — start: Read more
|Categories: Cache, Clustering, Couchbase, Data models and architecture, Databricks, Spark and BDAS, Exadata, Hadoop, MarkLogic, MongoDB, MySQL, NoSQL, Open source, Schema on need, Structured documents, Web analytics||1 Comment|
MongoDB isn’t the only company I reached out to recently for an update. Another is DataStax. I chatted mainly with Patrick McFadin, somebody with whom I’ve had strong consulting relationships at a user and vendor both. But Rachel Pedreschi contributed the marvelous phrase “twinkling dashboard”.
It seems fair to say that in most cases:
- Cassandra is adopted for operational applications, specifically ones with requirements for extreme uptime and/or extreme write speed. (Of course, it should also be the case that NoSQL data structures are a good fit.)
- Spark, including SparkSQL, and Solr are seen primarily as ways to navigate or analyze the resulting data.
Those generalities, in my opinion, make good technical sense. Even so, there are some edge cases or counterexamples, such as:
- DataStax trumpets British Gas‘ plans collecting a lot of sensor data and immediately offering it up for analysis.*
- Safeway uses Cassandra for a mobile part of its loyalty program, scoring customers and pushing coupons at them.
- A large title insurance company uses Cassandra-plus-Solr to manage a whole lot of documents.
*And so a gas company is doing lightweight analysis on boiler temperatures, which it regards as hot data.
While most of the specifics are different, I’d say similar things about MongoDB, Cassandra, or any other NoSQL DBMS that comes to mind: Read more
|Categories: Business intelligence, Cassandra, Databricks, Spark and BDAS, DataStax, NoSQL, Open source, Petabyte-scale data management, Predictive modeling and advanced analytics, Specific users, Text||6 Comments|
One pleasure in talking with my clients at MongoDB is that few things are NDA. So let’s start with some numbers:
- >2,000 named customers, the vast majority of which are unique organizations who do business with MongoDB directly.
- ~75,000 users of MongoDB Cloud Manager.
- Estimated ~1/4 million production users of MongoDB total.
Also >530 staff, and I think that number is a little out of date.
MongoDB lacks many capabilities RDBMS users take for granted. MongoDB 3.2, which I gather is slated for early November, narrows that gap, but only by a little. Features include:
- Some JOIN capabilities.
- Specifically, these are left outer joins, so they’re for lookup but not for filtering.
- JOINs are not restricted to specific shards of data …
- … but do benefit from data co-location when it occurs.
- A BI connector. Think of this as a MongoDB-to- SQL translator. Using this does require somebody to go in and map JSON schemas and relational tables to each other. Once that’s done, the flow is:
- Basic SQL comes in.
- Filters and GroupBys are pushed down to MongoDB. A result set … well, it results.
- The result set is formatted into a table and returned to the system — for example a business intelligence tool — that sent the SQL.
- Database-side document validation, in the form of field-specific rules that combine into a single expression against which to check a document.
- This is fairly simple stuff — no dependencies among fields in the same document, let alone foreign key relationships.
- MongoDB argues, persuasively, that this simplicity makes it unlikely to recreate the spaghetti code maintenance nightmare that was 1990s stored procedures.
- MongoDB concedes that, for performance, it will ordinarily be a good idea to still do your validation on the client side.
- MongoDB points out that enforcement can be either strict (throw errors) or relaxed (just note invalid documents to a log). The latter option is what makes it possible to install this feature without breaking your running system.
There’s also a closed-source database introspection tool coming, currently codenamed MongoDB Scout. Read more
|Categories: Business intelligence, EAI, EII, ETL, ELT, ETLT, Market share and customer counts, MongoDB, NoSQL, Open source, Structured documents, Text||6 Comments|
Occasionally I talk with an astute reporter — there are still a few left — and get led toward angles I hadn’t considered before, or at least hadn’t written up. A blog post may then ensue. This is one such post.
There is a group of questions going around that includes:
- Is Hadoop overhyped?
- Has Hadoop adoption stalled?
- Is Hadoop adoption being delayed by skills shortages?
- What is Hadoop really good for anyway?
- Which adoption curves for previous technologies are the best analogies for Hadoop?
To a first approximation, my responses are: Read more
|Categories: Application areas, Data warehousing, Databricks, Spark and BDAS, EAI, EII, ETL, ELT, ETLT, Hadoop, Hortonworks, MapR, MapReduce, Market share and customer counts, Open source, Pricing||6 Comments|
At the highest level:
- Presto is, roughly speaking, Facebook’s replacement for Hive, at least for queries that are supposed to run at interactive speeds.
- Teradata is announcing support for Presto with a classic open source pricing model.
- Presto will also become, roughly speaking, Teradata’s replacement for Hive.
- Teradata’s Presto efforts are being conducted by the former Hadapt.
Now let’s make that all a little more precise.
Regarding Presto (and I got most of this from Teradata)::
- To a first approximation, Presto is just another way to write SQL queries against HDFS (Hadoop Distributed File System). However …
- … Presto queries other data stores too, such as various kinds of RDBMS, and federates query results.
- Facebook at various points in time created both Hive and now Presto.
- Facebook started the Presto project in 2012 and now has 10 engineers on it.
- Teradata has named 16 engineers – all from Hadapt – who will be contributing to Presto.
- Known serious users of Presto include Facebook, Netflix, Groupon and Airbnb. Airbnb likes Presto well enough to have 1/3 of its employees using it, via an Airbnb-developed tool called Airpal.
- Facebook is known to have a cluster cited at 300 petabytes and 4000 users where Presto is presumed to be a principal part of the workload.
Daniel Abadi said that Presto satisfies what he sees as some core architectural requirements for a modern parallel analytic RDBMS project: Read more
I talked with my clients at MemSQL about the release of MemSQL 4.0. Let’s start with the reminders:
- MemSQL started out as in-memory OTLP (OnLine Transaction Processing) DBMS …
- … but quickly positioned with “We also do ‘real-time’ analytic processing” …
- … and backed that up by adding a flash-based column store option …
- … before Gartner ever got around to popularizing the term HTAP (Hybrid Transaction and Analytic Processing).
- There’s also a JSON option.
The main new aspects of MemSQL 4.0 are:
- Geospatial indexing. This is for me the most interesting part.
- A new optimizer and, I suppose, query planner …
- … which in particular allow for serious distributed joins.
- Some rather parallel-sounding connectors to Spark. Hadoop and Amazon S3.
- Usual-suspect stuff including:
- More SQL coverage (I forgot to ask for details).
- Some added or enhanced administrative/tuning/whatever tools (again, I forgot to ask for details).
- Surely some general Bottleneck Whack-A-Mole.
There’s also a new free MemSQL “Community Edition”. MemSQL hopes you’ll experiment with this but not use it in production. And MemSQL pricing is now wholly based on RAM usage, so the column store is quasi-free from a licensing standpoint is as well.
I chatted with the MariaDB folks on Tuesday. Let me start by noting:
- MariaDB, the product, is a MySQL fork.
- MariaDB, product and company alike, are essentially a reaction to Oracle’s acquisition of MySQL. A lot of the key players are previously from MySQL.
- MariaDB, the company, is the former SkySQL …
- … which acquired or is the surviving entity of a merger with The Monty Program, which originated MariaDB. According to Wikipedia, something called the MariaDB Foundation is also in the mix.
- I get the impression SkySQL mainly provided services around MySQL, especially remote DBA.
- It appears that a lot of MariaDB’s technical differentiation going forward is planned to be in a companion product called MaxScale, which was released into Version 1.0 general availability earlier this year.
The numbers around MariaDB are a little vague. I was given the figure that there were ~500 customers total, but I couldn’t figure out what they were customers for. Remote DBA services? MariaDB support subscriptions? Something else? I presume there are some customers in each category, but I don’t know the mix. Other notes on MariaDB the company are:
- ~80 people in ~15 countries.
- 20-25 engineers, which hopefully doesn’t count a few field support people.
- “Tiny” headquarters in Helsinki.
- Business leadership growing in the US and especially the SF area.
MariaDB, the company, also has an OEM business. Part of their pitch is licensing for connectors — specifically LGPL — that hopefully gets around some of the legal headaches for MySQL engine suppliers.
MaxScale is a proxy, which starts out by intercepting and parsing MariaDB queries. Read more
|Categories: Database compression, Hadoop, IBM and DB2, Market share and customer counts, Mid-range, MySQL, Open source, Tokutek and TokuDB, Transparent sharding||1 Comment|