Learning is not a spectator sport

Complete listing of posts

  • Searching in Oracle Database documentation

    Searching in Oracle Database documentation

    Just a quick heads up with something I see from time to time in Chrome (but not in Firefox or any other browser). Occasionally when doing a search, the results are not limited as per my criteria.  For example, if I am searching for information about Spatial in the Licensing Guide: then when I click… Read more

  • Complex materialized views and fast refresh

    Complex materialized views and fast refresh

    Just a quick discovery that came across the AskTOM “desk” recently. We have an outstanding bug in some instances of fast refresh materialized views when the definition of the materialized view references a standard view. Here’s a simple demo of the issue – I’ll use a simplified version of the EMP and DEPT tables, linked… Read more

  • Standard Edition–different optimizer but still cool

    Standard Edition–different optimizer but still cool

    One cool technique that the optimizer can employ is the BITMAP CONVERSION TO ROWIDS method to take advantage of B-tree indexes in a means that we would normally associate with a bitmap index. This can be particularly useful with multiple predicates on individually indexed columns because it lets us establish the rows of interest before… Read more

  • UTL_FILE_DIR and 18c

    UTL_FILE_DIR and 18c

    I wrote a blog post called The Death of UTL_FILE which attracted a comment from a reader: “There is NO chance to stay at UTL_FILE as it is DESUPPORTED starting with database Version 18c” This is not the case, but since I wanted to clarify what has changed in 18c, it warrants this small but… Read more

  • More triggers are better

    More triggers are better

    Yes, you heard me correctly. If you have got one trigger on a table, then you might be surprised to find that perhaps having a second one will be a better option. Then again, I also love the sweet scent of a clickbaity, inflammatory blog post title to draw the readers in so you’ll just… Read more

  • DDL for constraints – subtle things

    DDL for constraints – subtle things

    The DBMS_METADATA package is very cool. I remember the days of either hand-crafting DDL statements based on queries to the data dictionary, or many a DBA will be familiar with running “imp show=y” or “imp indexfile=…” in order to then laboriously extract the DDL required from the import log file.  DBMS_METADATA removed all of those… Read more

  • The death of UTL_FILE

    The death of UTL_FILE

    In a previous post I covered a technique to improve the performance of UTL_FILE, but concluded the post with a teaser: “you probably don’t need to use UTL_FILE ever again”. Time for me to back that statement up with some concrete evidence. UTL_FILE can read and write files. This blog post will cover the writing… Read more

  • When WHEN went faster

    When WHEN went faster

    Yeah…try saying that blog post title 10 times in a row as fast as you can But since we’re talking about doing things fast, this is just a quick post about a conversation I had a twitter yesterday about the WHEN clause in a trigger.   That is an easy benchmark to whip up –… Read more

  • Juicing up UTL_FILE

    Juicing up UTL_FILE

    Think about your rubbish bin for a second. Because, clearly this is going to be an oh so obvious metaphor leading into UTL_FILE right?  OK, maybe a little explanation is needed. I have a basket next to my desk into which I throw any waste paper. It is where I throw my stupid ideas and… Read more

  • The simplest things….can be risky

    Java and Oracle expert Lukas Eder tweeted yesterday about a potential optimization that could be done when reviewing database SQL code. This looks to be a logical thing to do.  Why scan the table T twice to perform an update, when the same job could be done in a single pass.  The benefits seem obvious:… Read more

  • The AskTOM data model

    I popped out a tweet yesterday in Throwback Thursday style showing the date of the first question we took AskTOM – 18 years ago! Many entire computer systems don’t even last that long, and AskTOM hasn’t really needed to change that much in those 18 years. We’ve added a new skin, added the ability to… Read more

  • “Call me!” Many many times!

    Some readers might recall that classic Blondie track “Call me”.  Of course, some readers might be wishing that I wouldn’t harp on about great songs from the 80’s. But bear with me, there is a (very tenuous) link to this post. If you haven’t heard the song, you can jump to the chorus right here. … Read more