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Database Feed

Oracle Database, Oracle 10g, Oracle 11g, Oracle XE, Oracle RAC, Oracle Instant Client, Oracle Data Guard and Oracle Exadata resources, news, and support articles.

FIXED_DATE and LAST_ANALYZED

I tested this on Oracle 11.2.0.1. You need to be careful when looking at the LAST_ANALYZED column in USER_TABLES.

Oracle: How to move OMF datafiles in 11g and 12c

With OMF datafiles, you don't manage the datafile name. Then how do you set the destination when you want to move them to another mount point? Let's see how it is easy (and online) in 12c. And how to do it with minimal downtime in 11g.

testcase

I create a tablespace with two datafiles. It's OMF and goes into /u01

Piggyback commits

Not every commit results in a redo write. This is because there are multiple optimizations (some controlled by the user e.g. with COMMIT_LOGGING parameter, some automatic) that aim at reducing the number of redo writes caused by commits by grouping redo records together. Such group or “piggyback” commits are important for understanding log file sync waits and various statistics around it.

Index Growing Larger Than The Table

Here is a very simple demonstration of a case where an Index can grow larger than the table.  This happens because the pattern of data deleted and inserted doesn't allow deleted entries to be reused.  For every 10 rows that are inserted, 7 rows are subsequently deleted after their status is changed to "Processed".  But the space for the deleted entries from the index cannot be reused.
SQL>
SQL>REM Demo Index growth larger than table !
SQL>
SQL>drop table hkc_process_list purge;

Table dropped.

Getting Started with Windows VDI by Andrew Fryer

Virtual desktop infrastructure (VDI) is the practice of hosting a desktop operating system within a virtua

Intra-Database IORM in action

I have been teaching the Enkitec Exadata Administration Class this week and made an interesting observation I thought was worth sharing with regards to IO Resource Management on Exadata.

I have created a Database Resource Manager (DBRM) Plan that specifically puts a resource consumer group to a disadvantage. Actually, quite severely so but the following shouldn’t be a realistic example in the first place: I wanted to prove a point. Hang-on I hear you say: you created a DBRM plan-the post has IORM in the subject though: what gives? Please allow me to explain.

Join Us in the Fight For Net Neutrality

“Net Neutrality” is the simple but powerful principle that cable and broadband providers must treat all internet traffic equally. Whether you’re loading a blog post on WordPress.com, streaming House of Cards on Netflix, or browsing handcrafted tea cozies on Etsy, your internet provider can’t degrade your connection speed, block sites, or charge a toll based on the content that you’re viewing.

Securing Oracle DB Accounts With Default Passwords

One view I didn’t know about until recently is DBA_USERS_WITH_DEFPWD. This view appeared in 11g but it obviously passed me by. The reason it cropped up recently was a requirement to ensure that the default accounts in an Oracle database were not left with default passwords, regardless of their account status.

Quiz Night

I have a table with several indexes on it, and I have two versions of a query that I might run against that table. Examine them carefully, then come up with some plausible reason why it’s possible (with no intervening DDL, DML, stats collection, parameter fiddling etc., etc., etc.) for the second form of the query to be inherently more efficient than the first.

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