Exalytics vs. HANA: What are they thinking?

I’ve been trying to sort through the noise around Exalytics and see if there are any conclusions to be drawn from the architecture. But this post is more about the noise. The vast majority of the articles I’ve read posted by industry analysts suggest that Exalytics is Oracle‘s answer to SAP‘s HANA. See:

But I do not see it?

Exalytics is a smart cache that holds a redundant copy of aggregated data in memory to offload aggregate queries from your data warehouse or mart. The system is a shared-memory implementation that does not scale out as the size of the aggregates increase. It does scale up by daisy-chaining Exalytics boxes to store more aggregates. It is a read-only system that requires another DBMS as the source of the aggregated data. Exalytics provides a performance boost for Oracle including for Exadata (remember, Exadata performs aggregation in the RAC layer… when RAC is swamped Exalytics can offload some processing).

HANA is a fully functional in-memory shared-nothing columnar DBMS. It does not store a copy of the data.. it stores the data. It can be updated. HANA replaces Oracle… it does not speed it up.

I’ll post more on Exalytics… and on HANA… but there is no Exalytics vs. HANA competition ahead. There will be no Exalytics vs. HANA POCs. They are completely different technologies solving different problems with the only similarity being that they both leverage the decreasing costs of RAM to eliminate the expense of I/O to disk or SSD devices. Don’t let the common phrase “in-memory” confuse you.

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9 thoughts on “Exalytics vs. HANA: What are they thinking?

  1. Exalytics is comparable when hana is used for BI purposes. It uses a columnar in-memory database and loads data in just the same as hana does. The in memory database used is TimeTen, which is a proven oltp in memory database which could run any oltp system today should a vendor choose to support it (sap included).

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    • Hmmm… I do not see that, Joe… I’ll double-check. Exalytics is not TimesTen. It uses TimesTen as a special case. Exalytics must be hooked to a real DW and supports aggregates extracted from that database. It is an OLAP co-processor hooked to your DBMS. Let me see if I can find a link to support this…

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  2. The olap db is Essbase running in memory, this is to support the Hyperion EPM product set. All the analytics and reporting is out of the TimesTen IMDB. Just FYI, it seems that TimesTen came out of the same HP labs as the “P-Time” IMDB from “transact in memory inc” that SAP bought in 2005 as the basis of HANA. In fact I think Dr Cha who set that company up worked for Marie-Ann Neimat who still runs the Oracle TimesTen product…. Very incestuous the software industry!

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    • Here is a quote from Rittman Mead Consulting who have some hands-on with Exalytics: “Oracle Exalytics uses a specially-enhanced version of Oracle TimesTen, Oracle’s in-memory database, to cache commonly-used aggregates used in dashboards, analyses and other BI objects.” You can find the whole article here.

      It is pretty much as I suggested, Joe… Exalytics is an in-memory extension to some other DBMS: Oracle and MySQL, I think… but I’ve seen a reference to SQL Server somewhere. It is built on TimesTen but Exalytics is not TimesTen and not a full DBMS platform for a data warehouse. You could, I suppose, call it a Data Mart. It is nicely integrated with Oracle’s intelligent aggregate capabilities so that queries can be routed to Exalytics automatically. It provides a nice, if very expensive, co-processing capability… that offloads a significant workload from Exadata (and Exadata often needs some help). It does not, in my opinion, compete with HANA or any other DBMS.

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    • Just one clarification – P-Time is not the “basis” for HANA. SAP has had many in-memory technologies over the years – MaxDB/LiveCache and TREX among them. HANA shares technologies from all of these, including P-Time, from which HANA gets it’s rowstore technology. If anything, it is more based on TREX, which is the foundation for the BW Accelerator, which SAP has been shipping since 2005. BWA is similar to Exalytics – an in-memory caching engine for data stored in an SAP Business Warehouse database, except that BWA stores an entire cube’s data, not just aggregates as TimesTen is designed to hold in an Exalytics configuration.

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      • Interesting background, David… Thanks. So we might say that HANA, TimesTen, and Oracle are full DBMS products… While Exalytics and BWA are accelerators? This supports the position that HANA and Exalytics are not competitors…

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      • That is correct, Rob. TimesTen is certainly a good in-memory database product, but have crippled it’s use as a standalone DBMS, imo. For example, in the latest version, they have added columnar compression, but this is only licensable for Exalytics. And it’s use in Exalytics is only to store aggregates built from a separate DBMS (which of course Oracle would prefer to be on Exadata).

        Of course, I still think HANA compares well to TimesTen. For example, HANA has both row store and column store, as well as graph store. It also has in-database execution for SQL, MDX and SQLScript, and scales well across clusters as evidenced by our 16-node cluster testing – 100 billion rows with sub-second response time. We’re testing on a 100 node cluster now, so we’ll see how scale-out performs on that soon.

        Also, true MVCC support for point-in-time query results in both row and column stores, as well as temporal support for time-based queries. TimesTen has none of these, that I’m aware of.

        Cheers,
        David.

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