InfiniDB: The Good, The Bad and the Ugly
Last week the BBBT was visited by startup database company Calpont, although 'startup' hardly fits the bill considering the fact that the company was founded in 2000. I won't go into the company nor the BBBT session details; you can find the last one here. What I do want to blog about is the product itself. Infinidb comes in both a Community Edition (CE) and an Enterprise Edition (EE), where the latter contains MPP capabilities, monitoring tools and different support options. For more details, visit the comparison page. Since I don't have an MPP cluster available I took the CE for a spin and thought I'd share the results.
As you might have noticed on the edition comparison page, the core server features are the same for both CE and EE. That's good news compared to direct competitor Infobright. Infobright has stripped out DML (insert/update/delete) capabilities from the Community Edition. Some people would call this 'cripple ware' as the only way to update a datawarehouse table is to drop, recreate and reload it. 1-0 for InfiniDB already.
More on the good side: the installation process. The product installs in minutes and is only a 12.7 MB download. I downloaded the 64bit RPM version which requires two steps: extract the zip file and run the command rpm -i Calpont*.rpm as root. This will install the software in the default location /usr/local/Calpont. Then invoke the script /usr/local/Calpont/bin/install-infinidb.sh, and configure the InfiniDB Aliases with . /usr/local/Calpont/bin/calpontAlias and you're good to go. In my case: almost good to go since the data directories are now under /user/local/Calpont which is not my 12 SDD disk raid set. Simply mounting the data device to /usr/local/Calpont/data1 solves that problem too. Alternatively, you can of course move the data1 directory to a different location and create a symlink in the original spot. The command service infinidb start fires up the database engine and invoking idbmysql gives you command line access to the database. Remember, it's all MySQL so if you're familiar with that, working with InfiniDB is a breeze.
The MySQL thing is another piece of the goodies: all front end tools, including the MySQL workbench (query browser, admin console) can be used with InfiniDB as well. The same JDBC drivers you already have for MySQL can be used with InfiniDB as well. The only difference when creating a new table is the fact that you should specify InfiniDB as the engine, but that's about it.
The last item I'd like to mention here is the bulk loader. The TPC-H benchmark consists of 22 queries and the database contains 8 tables. The data files can be created using the dbgen utility and will generate pipe delimited text files with a .tbl extension. The default settings InfiniDB uses for bulk loading text files are also the pipe delimiter and a .tbl extension, what a convenience! Other than that, the file names have to be named exactly as the tables you want to load (so customer.tbl is data for the table customer) and placed in the Calpont data import directory. Invoking the command colxml
There's actually only one 'bad' thing about the current version of InfiniDB: it's not finished yet. Yes, it works, it's fast (more about that later), but there are still a couple of serious limitations. The most notable of these, at least when running a TPC-H benchmark, is the support for subqueries. Version 1.1.0 alpha didn't support any form of subquery, so even a select * from table where column in (select othercolumn from othertable) couldn't be run. Version 1.1.1 alpha, released on April 23, solved this last one, but more complex subquery constructs or correlated subqueries are not yet supported. The upgrade from 1.1.0 to 1.1.1 enabled InfiniDB to complete 10 of the 22 TPC-H queries, instead of the only 5 it could run a week ago. But, as I've said, this should only be a temporary problem. The roadmap shows that in a month or so, phase two of the subquery support should be available in the next alpha release, with GA (General Availability) for version 1.1. set at early July. By then we can have a look at the complete run and see how it behaves, also when multiple threads are running in parallel.
Calpont uses the 'no indexes needed' as one of the key benefits of the product; I tend to disagree on that one. It's nice that you don't need to explicitely specify indexes, but when a DBMS doesn't support any constraints AT ALL, well, that's plain ugly. Want to enforce a NOT NULL contraint? Bad luck. Primary/foreign key relationships? Ditto. You could argue that these features are not really mandatory in a data-warehouse, but without constraint and index support all the constraint enforcement must be built into the ETL process.
The $64,000 question...
There is actually only one single reason why anyone would want to use a column store like InfiniDB in the first place: performance! So the main question is: does it deliver? Yes, it does. Compared to MySQL the performance improvement is no less than spectacular. In fact, to date nobody has been brave (or patient) enough to try an SF100 TPC-H on MySQL so a direct comparison is not even available. There are however plenty of other comparisons that can be made. The 10 queries that do run already all outperform Greenplum single node edition (except for query11) for instance. Some queries are somewhat faster (Q10, Q12, Q18), some are 3-4 times faster (Q1, Q3, Q4, Q14, Q16), and query 6 is more than 20 times faster. For a disk based analytical database (InfiniDB doesn't seem to take as much advantage of memory as other products I evaluated) it's really, really fast. Query 1 is always a good indicator since it forces a full table scan on the largest fact table (600 million rows in this case). If you can do this in under a minute on my moderate hardware, you do have a potential winner.
My initial thoughts about InfiniDB when I first tested it weren't very positive, to say the least. But, given the fact that they are moving in the right direction and have kept their promised delivery dates so far, combined with the ease of installation, ease of use (it's all MySQL) and of course the already great performance, a second look is certainly warranted. Given the limitations of the direct competitors (Kickfire with its proprietary hardware, Infobright with its crippled community edition and lack of MPP/scale out capabilities), InfiniDB should be on the top of your shortlist when looking for a MySQL based data-warehouse solution.
Topic: InfiniDB: The Good, The Bad and the Ugly
Re: Sub-query support
1.5.2 just out there ready for download