Integrate SQL*Plus Scripts in SQL Developer
I envy my DBA colleagues when they work with the Oracle Database from the command line in an incredibly efficient way. They just call a series of scripts with some parameters to get the desired information. Everything looks so easy, so smooth, so natural. I’m…
Partition Pruning and NLS Settings
NLS (National Language Support) parameters are very useful for multilingual applications in an Oracle database. But it is important to understand their impact on query performance. I was aware that NLS is important for indexes, but never thought about its impact on partitioning. In a…
Bitmap-based COUNT(DISTINCT) Functions in Oracle 19c
Oracle 19c provides a set of new SQL functions for bitmap operations. They allow fast computation of COUNT(DISTINCT) expressions. What is the purpose of these functions? The Oracle documentation is very sparse, but at least it tells us that the main focus are Materialized Views on…
Materialized View Refresh for Dummies
Materialized Views are often used in data warehouses to improve query performance on aggregated data. But what if it takes too long to refresh the materialized views? Here are some basic rules to improve refresh performance. Unlike indexes, materialized views are not automatically updated with…
MemOptimized RowStore in Oracle Database 19c
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…
Issue with the Hint ENABLE_PARALLEL_DML
Performing an ETL with large data sets, it is often a good idea to run DML in parallel. But, in contrast to parallel query or DDL, parallel DML have to be explicitly enabled. You had to issue ALTER SESSION ENABLE PARALLEL DML in the past….
ORA-22905 when calling ODCI Table functions from PL/SQL
Back in 2015 I experimented using ODCITable* functions to dynamically parse delimited text (see blog post here.) Now blog reader Daniel Cabanillas points out, that it raises an error when used in PL/SQL. Silly me – I had only tried it out in SQL (my…
Dynamic Pivot with Polymorphic Table Function?
LiveSQL is great place to start playing with new features. It provides a couple of very helpful demo scripts explaining how polymorphic table functions work. There I found a new script few days ago which uses PTF for dynamic pivot! WOW! According to my subjective…
Polymorphic Table Functions (PTF), Part 4 – Table Semantic PTF
In the first three parts of the series we have seen how a PTF basically works, but we have focused on row-semantic PTF only. In this part we’ll look at the table semantic PTF. As a reminder, the main difference to row-semantic PTF is that…
Polymorphic Table Functions (PTF) , Part 3 – Row Replication
In the third part of the PTF-series we learn how a PTF can change the cardinality of the input data flow: return more or less rows as in the input. We’ll use the same simple table as in the part 2 and our new task…
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