2019-12-13
Do you use parameterless PL/SQL functions in your queries? Did you know that this may cause performance issues? In this blog post I explain why parameterless functions can be the reason for bad execution plans in any Oracle Database. I recently had to analyze this problem in a production system and thought […]
2019-02-17
Since February, 13 2019 Oracle Database 19c is available. I blogged about this feature here and here. Time for an update. So, what’s new in 19c regarding the MemOptimized Rowstore? Fast Lookup Works with JDBC Thin Driver I listed 16 prerequisites for the MemOptimized Rowstore in this blog post. The last one – “The […]
2018-06-19
On June, 10 2018 I blogged about the MemOptimized RowStore in Oracle Database 18c. If you haven’t read this post, it is a good idea to catch up now. I showed that accessing a memoptimized table t4 via the MemOptimized RowStore was around 60% slower than accessing a heap-organized table t1. I […]
2018-06-10
The MemOptimized RowStore introduced in Oracle Database 18c is designed to improve performance of simple queries accessing data via primary key columns only. An example of such a query is SELECT value FROM t WHERE key = :key where key is the only primary key column of table t. This feature is available […]
2012-12-23
From time to time I’m asked to aggregate strings from multiple records into a single column using SQL. Here’s an example, showing a comma separated list of ordered employee names per department based on the famous EMP and DEPT tables. Oracle introduced the aggregate function LISTAGG for that purpose in 11.2. If […]
2012-12-02
I’ve just bought a Sony DSC RX100 camera with an Apple iPad Camera Connection Kit. The kit contains an USB adapter and a SD Card adapter. I intend to copy photos to my iPad for review and backup purposes during my holidays. My son argued that the SD card adapter must be […]