Q: What’s this FAQ about ?
A: General information about Phat4Oracle
Q: What’s Phat4Oracle
A: Performance History Analysis Tool for Oracle. (Phat also meant something else I discovered later on http://en.wikipedia.org/wiki/Phat)
Q: Is there a Phat for any other RDBMS ?
A: Not that I know of, and I have no plans to make it for another RDBMS than Oracle. It’s just that the name phat.blogspot.com was already taken. So I came up with Phat4Oracle
Q: Why Phat ?
A: There are a lot of good performance & analysis tools out there for Oracle. But they cost ! You need consultants to implement them. You need hardware to host a performance warehouse. You need to install agents on all database servers. You need training to be able to use it. Phat’s free and simple, it’s for the ‘Poor Man’.
Q: What about the 10g ADDM, ASH, AWR, etc ?
A: ‘$’ too ! Turn it off after installing Oracle and creating your database, unless you donated the extra ‘$’ to Oracle. “Database Diagnostics Pack” and “Database Tuning Pack” are not free. Check out the “Oracle technology price list”, it can be found here at the moment I am writing this.
Q: Is Phat just as good as the other products ?
A: No, maybe, it depends. There’s no fancy GUI, not an UI of any kind. It doesn’t do low weight direct SGA access. You can measure as precise as your Statspack snapshot frequency. But from my experience: Phat can still do way more than 50% of all performance analysis tasks you need to do. Sometimes you have bad luck, bind variables are not used and the rotten queries get flushed out of the SGA before Statspack can catch them in a snapshot.
Q: Is it free ?
A: Yes ! I repeat, YES ! FREE ! Do with it what you want, but don’t sell it, don’t use it as part of your product, and please always keep my name and my messages in it. Let me have a little honour, this won’t cost you much ! Please ?
Q: So, I install it and my performance problems are solved ?
A: No. It’s only an analysis tool.
Q: Tool ?
A: Well . . . tool is a ‘bit’ overrated maybe. It’s just a bunch of views. You still need a method, knowlegde of the Oracle database, and a big heavy object to hit the one who wrote the queries.
Q: Is that all I need ?
A: No. This is what you also need:
- Statspack. This is used to collect the data with snapshots. Extra views have to be created in the PERFSTAT schema. In stead of letting Statspack spit out 30+ pages of numbers, you do some queries, and you’ll be comparing dozens of snapshots at once.
- A tool to run queries would be handy. SqlPlus is not very suitable for the queries you need to run, they’ll have a lot of columns you need to copy+past to a chart tool. Toad is nice for this task. Other tools could be suiteable too.
- Some piece of software to make graphs is great to have. The human brain is capable of spotting trends in graphs in a fraction of a second. It becomes a bit harder if you are presented a sheet with a few hundred numbers.
Q: What’s so special about Phat combined with Statspack ?
A: Now: that’s the most important question ! Statspack tells you a lot about one certrain interval. But if it tells you there were 100.000 logical I/O’s, is this a problem ? Is this a lot ? It depends, what’s your baseline ? You would need to compare a lot of Statspack reports to figure this out. This is where Phat comes in. It can give you the amount of logical I/O’s for all intervals. This will give you a little overview of trends and exceptions going on in your database.
Q: How does it work ?
A: You create a bunch of views on top of the Statspack schema. To do analysis you run queries on those views. In stead of looking at all metrics of one interval, you’ll be looking at a view which shows one metric across all intervals. This will give you the abillity to spot trands and anomalies.
Q: On what versions of Oracle will Phat work ?
A: Phat was made on 9i. A copy of the views have been backported to 8i. It runs fine on 10g, but it does not yet use all Statspack information 10g provides.
Q: So, how do I use it ?
A: Well, have a look around on this site. I did a lot of work producing some pages to get you started. Give me some feedback to keep me motivated.