Sunday, September 28, 2008

OOW'08 ACE Directors Forum Session

Lewis Cunningham kindly took the reins of organizing a unique session - a panel of ACE Directors. But instead of a panel didcussing some topic, it welomed questions from the audience. sort of stump the chump with the questions. Lewis couldn;t have been a more perfect moderator/host. Most amazing, he came up with the idea to hand out blank index cards for the attendees to fill out with their questions, which forced the questions to be clearer.

On the panel we had Brad Brown (TUSC), Eddie Awad, Tim Hill, Mark Rittman, Hans Forbrich and your truly. Here is a coverage on Mark Rittman's blog (with a picture of the crew) http://www.rittmanmead.com/2008/09/26/oracle-open-world-2008-day-5-exadata-storage-server-and-ask-the-oracle-ace-directors/

I was nervous; and who wouldn't be, with the pressure? Fortunately, we, as a panel, with the expert moderation by Lewis, could ace the volleys. some of the questions I responded to with my answers:

  • Q: Will Transparent Tablespace Encryption (TTE) spell the doom for Tranparent data Encryption (TDE)?
  • A: Not at all. TDE encrypts a specific column or columns. TTE encrypts everything the tablespace - all tables and all columns. So, the performance definitely impacted. However, the biggest difference is the encryption in the database. Both technologies encrypt data in storage; but TTE decrypts the data in the SGA. So index scans do not suffer in case of TTE. TDE does *not* decrypt the values in SGA; so index scans are rather useless. So, in the case where a data value will most likely be found in SGA, the TTE option works well. The penalty is in the time when data is loaded from the database to the SGA. Since that happens a lot less, this will not cause a serious issue. In case data is frequently aged out of the buffer cache, the TTE option may prove expensive and TDE might become relatively attactive.
  • Q: What approach would you recommend for upgrading a 10 GB database to 11g from 10g - Data Pump, Exp/Imp, Transportable Tablespace?
  • A: None of the above. I would go for a Direct Path Insert (insert with the APPEND hint) over DB Link. This allows me several benefits - (i) I can do a database capture and replay it on 11g to minimize the risk of something breaking after upgrade. (ii) I can do a database reorg at the time of the move, i.e. partition unpartitioned objects, etc. (iii) have minimal time for migration.
  • Q: What is your least favorite new feature in Oracle?
  • A: I would rather answer it as most "unnecessary" new feature. It would be bigfile tablespaces - hands down. I always recommend creating smaller datafiles for tablespaces, no more thna 32 GB. This reduces the risk significantly in case of failures. If a block media recovery fails due to whatever reason, you can at least restore the file (or switch over to a copy) quickly. The bigger the file, the more time will be for restore and recovery. A large number of files increase the checkpoint time. so, try to find a balance. But in any case, dump bigfiles.
  • Q: How has life changed for you after being an OCP?
  • A: Not in the least. I have been an OCP since 8i and I finishd 9i, 10g and now 11g upgrade exams. However, no one ever bothered to ask me if I am an OCP.

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