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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.

Deterministic functions sometimes are Deterministic, even on 10.2

A few years back, some colleagues of mine were bemoaning the fact that functions created as DETERMINISTIC weren’t actually implemented as such in 10.2. Just to be clear, this is no longer the case with Oracle 11. DETERMINISTIC functions actually are deterministic:

Why don’t more people know about the benefits of Scalar Subqueries?

Every now and then, I get involved in interviewing Oracle developers when we’re specifically after “performance” skills. I ask a range of fairly expansive questions but I always ask if they know what Scalar Subqueries are and why they can deliver amazing performance benefits. Not many people seem to have heard of Scalar Subqueries are and even fewer are aware of the caching benefits.

Advert – a new Blog to watch

A friend of mine who’s work and attitude towards Oracle performance and architecture I respect has just started blogging, so I thought I would give him a mention. Dave Webster, welcome to the world of blogging. I know from some discussions with Dave about blogging that he has a lot of things he wants to [...]

SQL*Plus Timers

SQL*Plus TIMING is a handy little utility that you can use to do a performance analysis on any commands or blocks run during a period. It is different from the SET TIMING command which is used to display timing data after each SQL command or PL/SQL block you run. Here is an example: TIMING SHOW [...]

Compiled new oci8(1.4.3) in PHP(5.3.3)

How to compile new oci8 in PHP source?

Using Flashback Database to perform PITR

Flashback database is great alternative for incomplete recovery because it is much less time consuming in some cases. You can find in documentation nice explanations how flashback database works so I won’t concentrate much on theory.

In this blog post I will perform simple demo case of point in time recovery using flashback database feature.

Database must be in ARCHIVELOG mode and FLASHBACK should be enabled.

Exclusive latches in memory. Oracle versions 7-11.2

Contrary to popular believe Oracle latches were significantly evolved through the last decade. Not only additional statistics appeared (and disappeared) and new (shared)  latch type was introduced,  the latch  itself was changed It is interesting to see how the latch was organized in the past and contemporary  versions. To see the latch in-memory seems hard, [...]

Oracle table reorganization: Online or Offline

When using tables with large amounts of rows and especially after a lot of rows have been deleted from such a table, reorganizing the table may improve the performance of the table.

Oracle knows two types of table reorganizations.

  • Rebuilding the table by means of recreating it
  • Rebuilding the table by shrinking its free space ( Oracle 10g and up )

Below the two methods are explained.

Rebuilding the table by means of recreating it

Oracle's Broken Links

It seems that like me, people like Tim Hall are finding some of the changes regarding the amalgamation of sites within Oracle a little frustrating.

I've noticed many of the comments within OTN contain links to pages that just aren't there any more.

This OTN entry here mentions a vital link to

Exadata storage server software released

As of this afternoon, version of Oracle’s Exadata storage server software, is out in the wild. This is the first publicly available version of the branch, a major release including a full OS image with an update to Oracle Enterprise Linux 5.5. A number of bugs causing cell server crashes and [...]

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