Last week I needed the latest security patch for a new install of Oracle Application Server. After spending an inordinate amount of time on Oracle’s site I finally found it. Then I thought “I wonder if there’s an RSS feed for this?”

So I copied the URL out of IE and into a modern browser (Firefox in this case) and sure enough, I got the familiar feed icon in the location bar. I then proceeded to add the link to my RSS aggregator and can now find the updates without hassle!

So, if you’re looking for the latest security alerts from Oracle, here’s the link If you are using a news aggregator or portal which allows RSS you should consider adding the URL to your aggregator so you’ll always have the links to the latest patches handy.

oracle, rdbms, security, database

Satya commented on my post about finding the first or second Monday in a month asking how to find the last Saturday of a year using SQL. This is a good question as I think it is typical of the battles people fight with dates in Oracle.

So here we go… For this example we’ll use sysdate but you can use a date column or a to_date instead.

SQL> select sysdate from dual;

SYSDATE
---------
13-SEP-06

Now we’ll jump forward a year and start working backwards:

SQL> select sysdate+numtoyminterval(1, 'YEAR') from dual;

SYSDATE+N
---------
13-SEP-07

Now that we’re safely into next year we’ll reel it back to January 1st of next year using the trunc function to truncate the date down to the year.

SQL> select trunc(sysdate+numtoyminterval(1, 'YEAR'), 'YEAR') from dual;

TRUNC(SYS
---------
01-JAN-07

To work with the last week of the year we’ll go back 8 days. We need to go back 8 instead of 7 because we’re going to use the next_day function later which only looks after the date it is passed.

SQL> select trunc(sysdate+numtoyminterval(1, 'YEAR'), 'YEAR') - 8 from dual;

TRUNC(SYS
---------
24-DEC-06

Now we use the next_day function to look for the next Saturday after the date we’ve got.

SQL> select next_day(trunc(sysdate+numtoyminterval(1, 'YEAR'), 'YEAR') - 8, 'SATURDAY') from dual;

NEXT_DAY(
---------
30-DEC-06

So we figured out the last Saturday of this year by taking today’s date, adding one year, going back to January 1 of that year, stepping back 8 days from then and looking for the next Saturday.

Hope this helps Satya! Thanks for the great question.

oracle, dates, database, sql, dba, dbms, database development, database programming

Apple's Xserve RAIDIt looks like Oracle has decideded to adopt Apple’s XServe RAID as a low-cost storage solution

Based on our own experience with Apple technology, Xserve RAID is a great match for applications running Oracle.

With the appetite of one to two petabytes annually Oracle is of course looking to control costs and the SATA-based Xserve RAID combines value, capacity, performance and availability. The current top configuration offers 7000GB on dual RAID controllers with redundant power and cooling for a mere $12999. Sure that’s the price of a small car, but it works out to only $1.86/GB for some serous industry-level storage.

Thanks to Zach for sending this on to me.

apple, oracle, xserve, raid, xserve raid, storage, disk, hard drive

While researching the effect of RAID 5 disk configuration on Oracle databases I came accrost more than I thought I expected on the topic.

With disk as cheap as it is today there is no reason to ever use RAID 5 on an Oracle database. Even for a database which sees only a moderate amount of updates the performance loss incurred by using RAID 5 is too high. RAID 1 or some combination of RAID 1 and RAID 0 should be used when high availability is required. Database 10g users should also consider allowing Oracle’s new Automatic Storage Management to handle redundancy on un-mirrored disks (or even raw partitions.)

But don’t take my word for it. Here are some opinions from some notable Oracle administrators:

Oracle Database RAID 5
Mark Rittman

No RAID5. Use RAW whenever possible and consider RAID10 or 0+1. RAID 5 can severely affect performance on highly updated databases.

Oracle Database Administration: The Essential Reference
David Kreines & Brian Laskey

RAID-5 is, in fact, very powerful and inexpensive. It is also a technology to be avoided in most cases when configuring your Oracle database! This may seem a harsh statement, but the reality is that although RAID-5 provides good levels of data protection at a low monetary cost, this comes at a very high cost for disk I/O. In particular, write operations on RAID-5 arrays can be orders of magnitude slower than the same operations on a single disk.

Oracle and RAID usage
Mike Ault

Use RAID10 when possible, RAID5 if it is not. Size the array based on IO needs first, then storage capacity and you can’t go wrong.

Disk Management for Oracle
Donald Burleson

Oracle recommends using (SAME) Stripe And Mirror Everywhere (a.k.a., RAID 1+0) for all systems that experience significant updates. This is because of the update penalty with RAID 5 architectures.

Using RAID 5 for a high-update Oracle system can be disastrous to performance, yet many disk vendors continue to push RAID 5 as a viable solution for highly updated systems.

RAID 5 is not recommended for high-update Oracle systems. The performance penalty from the parity checking will clobber Oracle performance.

If you’re still not convinced check out Baarf.com. This site is committed to the Battle Against Any Raid Five (or four or free, uh, three.) The site has links to several more articles exposing the perils of RAID 5.

oracle, rdbms, dba, systems administration, sysadmin, raid, raid 5

Sun T2000Well things weren’t quite as easy as Johnathan Schwarts, now CEO of Sun implied when he wrote “if you write a blog that fairly assesses the machine’s performance (positively or negatively), send us a pointer, we’re likely to let you keep the machine.” but after a little extra paperwork and a more formal contest we have won a Sun Fire T2000 server!

That’s right! Thanks to considerable help from Scott Maziarz, an outstanding Plymouth State University IT major who has been working with me on all things Oracle, we were able to evaluate the performance of the Sun Fire T2000 against our existing Sun Fire V440. Scott ran a series of tests based on some jobs we run daily to recreate data marts in our production system.

Scott ran the tests and compiled the results and I wrote up our findings here on Life After Coffee for others to see (and so we could enter the contest.) We ended up shipping our T2000 back as our 60 day trial was over before we were chosen for the contest, but now Sun says they’ll be sending it back to us.

So a big thanks to Scott for his help and to Sun for running this program and choosing us as a winner!

« Previous PageNext Page »