Home » Tag Archives: Databases (page 2)

Tag Archives: Databases

Solving Problems with the Right Technology: Hadoop and RDBMS

In some circles today there is a sort of ‘Hadoop vs. RDBMS’ debate ongoing. Often the discussion casts Hadoop as the obvious heir apparent in the data processing world, with RDBMS cast as your father’s Oldsmobile. This debate is somewhat misdirected and the discussion could lead organizations away from the strategy they really should be following, namely a strategy of ...

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A tale of troubleshooting database performance, with Cassandra and sysdig

Gianluca Bordello is an engineering manager at Sysdig, where he wears many hats. He’s a core developer of sysdig, an open source troubleshooting tool for Linux and containers, and spends his days dealing with backend development, performance analysis and cloud infrastructure management. Introduction As far as databases go, I’m a  huge fan of Cassandra: it’s an incredibly powerful and flexible ...

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Using Oracle AQ via Java 8 Streams

java-interview-questions-answers

One of the most awesome features of the Oracle database is Oracle AQ: Oracle Database Advanced Queuing. The AQ API implements a full fledged, transactional messaging system directly in the database. In a classic architecture where the database is at the center of your system, with multiple applications (some of which written in Java, others written in Perl or PL/SQL, ...

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Reactive Database Access – Part 3 – Using jOOQ with Scala, Futures and Actors

We’re very happy to continue our a guest post series on the jOOQ blog by Manuel Bernhardt. In this blog series, Manuel will explain the motivation behind so-called reactive technologies and after introducing the concepts of Futures and Actors use them in order to access a relational database in combination with jOOQ. Manuel Bernhardt is an independent software consultant with ...

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Using the JDBC Insert Features in Oracle

java-interview-questions-answers

Introduction In this article I will show an example of how to use the JDBC bulk insert features supported by Oracle — and which are specific to Oracle. For more details on why one might like to resort to using bulk inserts in general, e.g., performance considerations when certain circumstances warrant, see the JCG article, “JDBC Batch Insert Example ” ...

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Safe Database Migration Pattern Without Downtime

I’ve been doing a continuous delivery talk for a while now and during my talk I describe a pattern of how to safely migrating one database to another database without downtime. Since many people contacted me and asked for more details about it, I will describe it here in more details as promised. You can use this pattern to migrate ...

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Does PostgreSQL Have an ORA-01795-like Limit?

The Oracle database requires that no more than 1000 entries be used in a SQL IN portion of a WHERE clause and will throw an ORA-01795 error if that number is exceeded. If a value needs to be compared to more than 1000 values, approaches other than use of IN must be applied. I wondered if this limitation applies to ...

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A beginner’s guide to read and write skew phenomena

Introduction In my article about ACID and database transactions, I introduced the three phenomena described by the SQL standard: dirty read non-repeatable read phantom read While these are good to differentiate the four isolation levels (Read Uncommitted, Read Committed, Repeatable Read and Serializable), in reality, there are more phenomena to take into consideration as well. The 1995 paper (A Critique ...

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