Tag: dba

Your New Years Resolution

Aligning roughly with the calendar year, based on the Chinese zodiak we’re about to go from the year of the dog to the year of the pig. But for me, in the “Information Technology Zodiak” , 2018 was the year of the hack, just…

Automatic sequences not being dropped

One of the nice new things in 12c was the concept of identity columns. In terms of the functionality they provide (an automatic number default) it is really no different from anything we’ve had for years in the database via sequences, but native support…

The phantom tablespace

(Cueing my deep baritone Morpheus voice…) What if I told you that you can reference non-existent tablespaces in your DDL? OK, it sounds like a gimmick but there is a real issue that I’ll get to shortly. But first the gimmick I’ve created a…

18c and the ignoring of hints

  One of the new features in 18c is the ability to ignore any optimizer hints in a session or across the entire database. A motivation for this feature is obviously our own Autonomous Data Warehouse, where we want to optimize queries without the…

Add ORDER BY to make ANY query faster

Yes it’s SCBT day here in Perth! SCBT = Silly Click Bait Title This post is just a cautionary tale that it is easy to get caught up judging SQL performance solely on a few metrics rather than taking a more common sense approach…

Interval versus Range partitions

One of the nice things about partitioning in the database is that partition pruning can quickly eliminate the requirement to read large amounts of data when the partitioning key(s) are appropriately provided in your queries (and DML). This also extends to queries where the…

18c XE–running locally

There’s already a few blog posts out there, showing people (easily) getting their 18c XE instance downloaded, installed and running, so I won’t rehash that here. For the majority of people, I’d imagine they’ll have their XE instance running on a small box and…