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November 2016

What I forgot and had to relearn about DESC indexes

The title for this blog post is probably more catchy than the post itself but the election is close so every sort of campaign is allowed, right?
This post is another one of those “I knew it, but I forgot and got bitten back” blog post so hopefully next time I see it I’ll be quicker in recognizing such behavior.

The goal of the SQL is to quickly return the Top-N rows  that match some filter condition(s), descendingly sorted by one of such columns. Pretty common requirement if you consider the filter/sort column to be a date one (“give me the last day worth of transactions, starting with the most recent ones”) and many people would solve using a DESC index on the date column.

Oracle Database Block Visualizer

Recently I wanted to demonstrate to some people on my training, how Oracle database maintains blocks in a datafile – what happens after truncate, truncate with drop storage clause, delete, regular insert, direct path insert and so on…

I didn’t find any tool for that so I’ve written my own. It’s core code is based on my previous database block research – project RICO http://blog.ora-600.pl/2015/09/03/rico/

Tool is very small and simple and right now it supports only regular blocks with data and no compression.

And this is how it works – let’s create a tablespace and 3 new tables in HR schema:

Oracle Database Block Visualizer

Recently I wanted to demonstrate to some people on my training, how Oracle database maintains blocks in a datafile – what happens after truncate, truncate with drop storage clause, delete, regular insert, direct path insert and so on…

I didn’t find any tool for that so I’ve written my own. It’s core code is based on my previous database block research – project RICO http://blog.ora-600.pl/2015/09/03/rico/

Tool is very small and simple and right now it supports only regular blocks with data and no compression.

And this is how it works – let’s create a tablespace and 3 new tables in HR schema:

Scoop – First glance of the new Oracle Live SQL?

When I was at OOW this year I saw the new (?) Oracle Live SQL…

Huge Presentation – Working with Oracle Database in C#, VBScript, and Excel; Enhancing Visual Manufacturing 8.0.0

November 2, 1016 In late September 2016 I gave a somewhat long presentation that lasted roughly four and a half hours.  Surprisingly, the only glitch that I encountered during the live demonstration portion of the presentation was due to an apparent bug, at least in Excel 2010, that causes long object names (specifically checkbox names on […]

Approximate Aggregate Transformation (AAT)

There are situations where approximate results are superior than exact results. Typically, this is the case when two conditions are met. First, when the time and/or resources needed to produce exact results are much higher than for approximate results. Second, when approximate results are good enough. Approximate results are for example superior in case of exploratory queries or when results are displayed in a visual manner that doesn’t convey small differences.

Oracle Database 12.2.0.1 – PL/SQL JSON functionality

One functionality area in Oracle Database 12.2.0.1 that now also supports the handling of JSON…

How you should or shouldn’t design, program for, a performing database environment

My good friend Toon Koppelaars created a cool and very interesting, learning video about how…

"Cost Based Optimizer: Grundlagen – mit Update für Oracle 12c" Artikel (German)

Seit gestern steht auf der "Informatik Aktuell"-Seite mein Artikel "Cost Based Optimizer: Grundlagen – mit Update für Oracle 12c" zur Verfügung.

Er stimmt auch inhaltlich auf meinen Vortrag bei den IT-Tagen 2016 am 13. Dezember ein.
Sollte Sie das Thema interessieren, lade ich Sie hiermit also herzlich zu meinem Vortrag ein, bei dem ich das Thema auch mit Live-Demonstrationen vertiefen werde.

csv.sh

UNIX/Linix shell-script to call the Perl script “csv.pl”, which calls the CSV function in the DUMP_DATA package in PL/SQL.  This is one of the fastest ways to dump data from any Oracle table or table partition to a text file in CSV (comma-separated values) format.