Posts by Don Seiler

Setting up Network ACLs in Oracle 11g… For Dummies

Oracle’s post-upgrade network ACL setup documentation is much more confusing than it needs to be, at least for simple minds like me. A colleague stepped forward with a simple set of commands for a basic setup that even the tired and stressed can understand. I’ll share that here, with some basic explanation.

Turn Off db_cache_advice To Avoid Latch Contention Bugs

A couple of weeks ago, we noticed some timeouts in some of our standard Oracle RDBMS health check scripts on a new instance. At first the timeouts were infrequent, but over the course of a week started to grow in frequencey until the point where none of the checks were finishing in the allowed timeframe. We ran an AWR report, and tucked far down in the “Latch Activity” section, a colleague noticed this…

Sending Timezone-Aware Email with UTL_SMTP

I’m back again with another in what I hope will be a long line of “Quick Tips for Newbies” series. At Pythian, we are spread across multiple timezones, since it wasn’t too long ago that everyone was in Ottawa, this is something that still presents little quirks. One such quirk involved email generated by one of our internal Oracle instances—via a stored procedure that used UTL_SMTP to send the messages—did not have timezone information in the “Date” email header. As a result, they would be stamped with the hour in Eastern timezone (Ottawa time), but the mail clients would think that hour was local. Even if you aren’t sending email to all the ends of the Earth, it won’t hurt to make your messages timezone-aware. I’m sure it will save some confusion and frustration down the line. Here`s how.

RMAN Redundancy is not a Viable Retention Policy

I have always had a preternatural dislike for using REDUNDANCY as a retention policy for Oracle RMAN, greatly preferring RECOVERY WINDOW instead, simply because REDUNDANCY doesn’t really guarantee anything valuable to me, whereas RECOVERY WINDOW guarantees that I’ll be able to do a point-in-time recovery to anytime within the past x days. The two biggest points to take away are: Tape backup failures are still serious backup failures and should be treated as such, even if you backup to disk first; and, REDUNDANCY is not a viable retention policy. In my house, it is configuration non grata.

GNU basename in PL/SQL

In the process of scripting a database migration, I was in need of something akin to the GNU basename utility that I know and love on Linux. basename is most famous for taking a full file path string and stripping away the leading path component, returning just the name of the file. This can be emulated in PL/SQL with calls to SUBSTR and INSTR, like this…

Ubiquity and Tahiti: Together At Last!

You can load the command in your Ubiquity-enabled browser by visiting this page. Ubiquity users should already see the notice at the top of the page to subscribe to this command. You can view the source code at the end of this post.

Does Oracle’s Block Change Tracking File Shrink?

.Recently in IRC (#oracle on freenode, to be precise), a fresh face asked if the Block Change Tracking file ever shrinks. I began to do some reading. For some reason, actually reading the official tahiti docs was last on my list. A search of the 10gR2 docs quickly yielded this (from RMAN Incremental Backups)…

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