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August 2008

Effective Testing

I’ve been following a number of threads on forums.oracle.com recently – the quality of discussion seems to have improved markedly there since I gave up on it in 2001. Anyway there was a thread about interpreting the AWR report that Oracle provides (at extra cost) and which is very smilar to the Statspack report. The [...]

The simplest query for checking what’s happening in a database

Update: If you are able to download & run scripts, it's probably better to use my Snapper and @ashtop.sql tools for performance analysis. Neither of these scripts require any installation, Ashtop requires Diagnostics Pack (as it uses ASH), Snapper doesn't even need that - it can also run on Standard Edition! Search for them in my blog, or check an intro video in my YouTube channel.
When someone asks you to take a quick look into database performance and for whatever reason you can’t run your usual scripts or performance tools on there, ), then what query would you run first?

The simplest query for checking what’s happening in a database

Update: If you are able to download & run scripts, it's probably better to use my Snapper and @ashtop.sql tools for performance analysis. Neither of these scripts require any installation, Ashtop requires Diagnostics Pack (as it uses ASH), Snapper doesn't even need that - it can also run on Standard Edition! Search for them in my blog, or check an intro video in my YouTube channel.
When someone asks you to take a quick look into database performance and for whatever reason you can’t run your usual scripts or performance tools on there, ), then what query would you run first?

How I got picked for special attention in Denver International Airport

So my wife Anette and I are on our way home from Tim's wedding.

We flew British Airways both ways. In Copenhagen I told a lady at the BA check-in counter that I might have discovered a way for terrorists to put bombs on planes without being on the plane themselves.

You see, the last couple of times where I have had to change terminals in Heathrow and there's been approximately two hours or less between the flights my bags haven't made it.

So if the bags are onboard a plane but the passenger doesn't show up, they'll pull the bags. But if the bags are delayed they'll let the passenger fly without his luggage.

Application Express and E-Business Suite 11i.

I’m just starting an installation of Oracle APEX 3.1.1 into one of our development ebs instances for 2 reasons.

To provide a small applet to a project team
To provide the infrastructure for the dbas to write their own little applets.

I chose this method for the following reasons (unordered)

it’s fairly cool
we know pl/sql much better than java
we [...]

Library cache latches gone in Oracle 11g

In Oracle 11g even more library cache operations have been changed to use KGX mutexes instead of latches.

In Oracle 10.2.0.2+ the library cache pin latch usage was replaced with mutexes whenever _kks_use_mutex_pin was true, also few other things like V$SQLSTATS arrays and parent cursor examination were protected by mutexes. However the traversing of library cache hash chains (the right child cursor lookup using kksfbc()) was still protected by library cache latches which could become a problem with frequent soft parsing combined with too little cursor cache and long library cache hash chains (remember, the library cache latches were always taken exclusively even for plain hash chain scanning).

In 11g all library cache related latches except “library cache load lock” are gone and corresponding operations are protected by mutexes instead. The “library cache” latches have been replaced by “Library Cache” mutexes for example.

Library cache latches gone in Oracle 11g

In Oracle 11g even more library cache operations have been changed to use KGX mutexes instead of latches.

In Oracle 10.2.0.2+ the library cache pin latch usage was replaced with mutexes whenever _kks_use_mutex_pin was true, also few other things like V$SQLSTATS arrays and parent cursor examination were protected by mutexes. However the traversing of library cache hash chains (the right child cursor lookup using kksfbc()) was still protected by library cache latches which could become a problem with frequent soft parsing combined with too little cursor cache and long library cache hash chains (remember, the library cache latches were always taken exclusively even for plain hash chain scanning).

In 11g all library cache related latches except “library cache load lock” are gone and corresponding operations are protected by mutexes instead. The “library cache” latches have been replaced by “Library Cache” mutexes for example.

Tim is getting married...

Anette and I are in Denver, Colorado these days, because Tim Gorman is getting married to Lori tonight (Saturday). It's a hot wedding: This is, I think, the 20th day in a row with over 90 degrees Fahrenheit, which makes it the hottest period since 1857 or something like that.

Tim is very well known in the Oracle community: He spent many years inside Oracle where I had the pleasure of communicating a lot with him on the wonderful HELPKERN list there.

He also wrote a couple of books and contributed to the Tales of The OakTable book. Here's his website: http://www.evdbt.com/

Good luck to Lori & Tim! (said the guy on his third marriage...)