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tl;dr: specify the --user root argument:

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This is a short summary discussing what the options are for integrating Oracle RDBMS into Kafka, as of December 2018 (refreshed June 2020). For a more detailed background to why and how at a broader level for all databases (not just Oracle) see this blog and this talk. What techniques & tools are there? Franck Pachot has written up an excellent analysis of the options available here. As of June 2020, this is what the line-up looks like:

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The Kafka Connect JDBC Connector by default does not cope so well with: NUMBER columns with no defined precision/scale. You may end up with apparent junk (bytes) in the output, or just errors. TIMESTAMP WITH LOCAL TIME ZONE. Throws JDBC type -102 not currently supported warning in the log. Read more about NUMBER data type in the Oracle docs. tl;dr : How do I make it work? There are several options:

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This article is part of a series exploring Streaming ETL in practice. You can read about setting up the ingest of realtime events from a standard Oracle platform, and building streaming ETL using KSQL. This post shows how we take data streaming in from an Oracle transactional system into Kafka, and simply stream it onwards into Elasticsearch. This is a common pattern, for enabling rapid search or analytics against data held in systems elsewhere.

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This is the detailed step-by-step if you want to recreate the process I describe in the Confluent blog here I used Oracle’s Oracle Developer Days VM, which comes preinstalled with Oracle 12cR2. You can see the notes on how to do this here. These notes take you through installing and configuring: Swingbench, to create a sample “Order Entry” schema and simulate events on the Oracle database Oracle GoldenGate (OGG, forthwith) and Oracle GoldenGate for Big Data (OGG-BD, forthwith) I’m using Oracle GoldenGate 12.

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Some notes that I made on installing and configuring Oracle GoldenGate with Confluent Platform. Excuse the brevity, but hopefully useful to share! I used the Oracle Developer Days VM for this - it’s preinstalled with Oracle 12cR2. Big Data Lite is nice but currently has an older version of GoldenGate. Login to the VM (oracle/oracle) and then install some useful things: sudo rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm sudo yum install -y screen htop collectl rlwrap p7zip unzip sysstat perf iotop sudo su - cd /etc/yum.

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Here’s where I’ll be! If you use Google Calendar you can click on individual entries above and select copy to my calendar - which of course you’ll want to do for all the ones I’ve marked as [SPEAKING] :-) Here’s a list of all the Apache Kafka talks at OpenWorld and JavaOne, most of which I’ll be trying to get to.

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The Replicat was kapput: GGSCI (localhost.localdomain) 3> info rkconnoe REPLICAT RKCONNOE Last Started 2017-09-12 17:06 Status ABENDED Checkpoint Lag 00:00:00 (updated 00:46:34 ago) Log Read Checkpoint File /u01/app/ogg/dirdat/oe000000 First Record RBA 0 So checking the OGG error log ggserr.log showed 2017-09-12T17:06:17.572-0400 ERROR OGG-15051 Oracle GoldenGate Delivery, rkconnoe.prm: Java or JNI exception: oracle.goldengate.util.GGException: Error detected handling operation added event. 2017-09-12T17:06:17.572-0400 ERROR OGG-01668 Oracle GoldenGate Delivery, rkconnoe.prm: PROCESS ABENDING. So checking the replicat log dirrpt/RKCONNOE_info_log4j.

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There are various reasons for this error, but the one I hit was that the table name is case sensitive, and returned from Oracle by the JDBC driver in uppercase. If you specify the tablename in your connecter config in lowercase, it won’t be matched, and this error is thrown. You can validate this by setting debug logging (edit etc/kafka/connect-log4j.properties to set log4j.rootLogger=DEBUG, stdout), and observe: (I’ve truncated some of the output for legibility)

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Oracle’s excellent Big Data Lite VM has been updated, to version 4.5. Download it here Changes: CDH 5.5 -> 5.7 Big Data Spatial and Graph 1.1 -> 1.2 Big Data Discovery 1.1 -> 1.2 Oracle Big Data Connectors 4.4 -> 4.5 Oracle NoSQL 3.5 -> 4.0 GoldenGate 12.2.0.1 -> 12.2.0.1.1

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Recently added to the oracledi project over at java.net is an adaptor enabling Oracle GoldenGate (OGG) to send data to Elasticsearch. This adds a powerful alternative to [micro-]batch extract via JDBC from Oracle to Elasticsearch, which I wrote about recently over at the Elastic blog. Elasticsearch is a ‘document store’ widely used for both search and analytics. It’s something I’ve written a lot about (here and here for archives), as well as spoken about - preaching the good word, as it were, since the Elastic stack as a whole is very very good at what it does and a pleasure to work with.

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In Oracle 11g, the DBMS_STATS procedure GATHER_SCHEMA_STATS takes a parameter ‘options’ which defines the scope of the objects processed by the procedure call, as well as the action. It can be either GATHER or LIST (gather the stats, or list out the objects to be touched, respectively), and AUTO, STALE or EMPTY (defining the object selection to process). GATHER on its own will gather stats on all objects in the schema GATHER EMPTY / LIST EMPTY is self-explanatory - objects with no statistics.

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Have you defined CLIENT_ID in your OBIEE RPD yet? You really ought to. As well as helping track down users of troublesome queries, it also tags dump files with the OBIEE user of an offending query should the worst occur: For details, see: Identify your OBIEE users by setting Client ID in Oracle connection Instrumenting OBIEE for tracing Oracle DB calls

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Here’s a scenario that’ll be depressingly familiar to most reading this: after ages of running fine, and no changes to the code, a query suddenly starts running for magnitudes longer than it used to. In this instance it was an ETL step which used to take c.1 hour, and was now at 5 hours and counting. Since it still hadn’t finished, and the gods had conspired to bring down Grid too (unrelated), I generated a SQL Monitor report to see what was happening: [sourcecode language=“sql”] select DBMS_SQLTUNE.

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There is a well-documented problem relating to DBMS_STATS.COPY_TABLE_STATS between partitions where high/low values of the partitioning key column were just copied verbatim from the source partition. This particular problem has now been patched (see 8318020.8). For background, see Doug Burns’ blog and his excellent paper which covers the whole topic of statistics on partitioned tables. This post Maintaining statistics on large partitioned tables on the Oracle Optimizer blog details what the dbms_stats.

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Chucking a stick in the spokes of your carefully-tested ETL/BI … My opinion is that automated stats gathering for non-system objects should be disabled on Oracle Data Warehouses across all environments. All it does it cover up poor design or implementation which has omitted to consider statistics management. Once you get into the realms of millions or billions of rows of data, the automated housekeeping may well not have time to stat all of your tables on each run.

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Just because something produces the correct numbers on the report, it doesn’t mean you can stop there. How you are producing those numbers matters, and matters a lot if you have an interest in the long-term health of your system and its ability to scale. OBIEE is the case in point here, but the principle applies to any architecture with >1 tiers or components. Let me start with a rhetorical question.

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Chris Mellor at The Register posted an interesting article a couple of days ago, entitled HP and Violin build Oracle Exadata killer. The slidedeck has been removed from HP’s FTP site, but a bit of Google magic throws up a couple of mirror copies. It’s an entertaining read (“Do a Proof of Concept! 94% win rate!! We can and do win against Exadata!!”), and a nice illustration of the FUD techniques that companies use in marketing their products against others.

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Whilst perusing the Oracle database documentation, I noticed something which caught my eye: As well as reading the documentation online as HTML or downloading as PDF for viewing on your computer etc, you can also download it in formats (Mobi and ePub) designed for eReaders such as the Kindle and iPad (the latter obviously isn’t “just” an eReader). For information on format support, there’s a handy table on Wikipedia. It looks like the availability of mobi/epub files isn’t universal.

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