Oracle Scratchpad

November 7, 2016

Reorg

Filed under: fragmentation,humour,Oracle — Jonathan Lewis @ 5:31 pm GMT Nov 7,2016

A current question on the OTN database forum asks: “What’s the difference between object and tablespace reorganization?” Here’s an analogy to address the question.

I have three crates of Guiness in the boot (trunk) of my car, one crate has 4 bottles left, one has 7 bottles left and one has 2 bottles. I also have two cases of Louis Roederer Brut NV champagne, one case has 2 bottles left and one has only one. (I have two objects in my tablespace – one of type Beer, one of type Champagne – and my boot requires manual free space management .)

I move all the Guiness bottles into a single crate and all the champagne bottles into a single case. That’s a couple of “shrink space compact” calls – I’ve re-organised the objects to get all the bottles in each object close to each other, but the crates are still taking up space in the boot.

I take the two empty crates and the empty case out of the boot. That’s a couple of “resize” (or “shrink space” without “compact”) calls that free up space in the boot.

I now want to load a port barrel into car, but it won’t fit until I slide the remaining beer crate and champagne case together at one side of the boot. That’s a couple of “move” commands that have reorganized the boot (tablespace) to make the free space usable.

 

6 Comments »

  1. Never mind the explanation, I will take the contents of your trunk.

    Comment by jkstill — November 7, 2016 @ 6:55 pm GMT Nov 7,2016 | Reply

  2. Fantastic analogy. Just one thing, where are you heading to now, in your car, with the Guiness, champagne and port? Just out of interest.

    Comment by patrickhurley — November 7, 2016 @ 10:13 pm GMT Nov 7,2016 | Reply

  3. You’ve changed. I remember the days when you’d only have 1/2 pint of cider! *{;-)

    Comment by Boneist — November 8, 2016 @ 8:34 am GMT Nov 8,2016 | Reply

  4. You can combine the port and Guiness to make a Purple Velvet – this is known as a “merge”.

    Comment by Phil A — November 8, 2016 @ 2:36 pm GMT Nov 8,2016 | Reply

    • Or maybe a cluster – though I don’t think champagne bottles would fit in a standard beer crate.

      It’s also possible to serve up Guiness mixed with Champagne: “Black Velvet” (invented to commemorate the death of Prince Albert) – traditionally drunk with oysters, I believe.

      Then there’s Champagne mixed with (tawny) port: “Nelson’s Blood” (invented to honour Admiral Lord Nelson after the battle of Trafalgar)

      Comment by Jonathan Lewis — November 8, 2016 @ 5:49 pm GMT Nov 8,2016 | Reply


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