Oracle

tanelpoder's picture

Oracle Session Snapper v3.10

Hi all, long time no see!  =8-)

Now as I’m done with the awesome Hotsos Symposium (and the training day which I delivered) and have got some rest, I’ll start publishing some of the cool things I’ve been working on over the past half a year or so.

The first is Oracle Session Snapper version 3!

There are some major improvements in Snapper 3, like ASH style session activity sampling!

When you troubleshoot a session’s performance (or instance performance) then the main things you want to know first are very very simple:

  1. Which SQL statements are being executed
  2. What are they doing, are they working on CPU or waiting.
  3. If waiting, then for what

Often this is enough for troubleshooting what’s wrong. For example, if a session is waiting for a lock, then wait interface will show you that. If a single SQL statement is taking 99% of total response time, the V$SESSION (ASH style) samples will point out the problem SQL and so on. Simple stuff.

However there are cases where you need to go beyond wait interface and use V$SESSTAT (and other) counters and even take a “screwdriver” and open Oracle up from outside by stack tracing :-)

When I wrote the first version of Snapper for my own use some 4-5 years ago I wrote it mainly having the “beyond wait interface” part in mind. So I focused on V$SESSTAT and various other counters and left the basic troubleshooting to other tools. I used to manually sample V$SESSION/V$SESSION_WAIT a few times in a row to get a rough overview of what a session was doing or some other special-purpose scripts.

However after Snapper got more popular and I started getting some feedback about it I saw the need for covering more with Snapper, not just the “beyond wait interface” part, but also the “wait interface” and “which SQL” part too.

marco's picture

Hotsos 2010 – Farewell…

Said farewell today to the guys I met in the lobby of the Omni Mandelay Hotel in Irving, Texas. The final bits of the Hotsos 2010 Symposium. It has been a good run.

By the way, what did you mean Doug, with “a big laptop”, regarding your new Sony VAIO ???

It isn’t that big…

Dougs New VAIO

;-)

marco's picture

Hotsos 2010 – A Training Day with Tanel Poder

My last day already, so I hereby leave you with some impressions from Tanel’s Training Day. Maybe until next year.

If you also want to learn from him, then here’s your chance in Holland. Scripts and tools used by Tanel can be found here.

8-)

marco's picture

Hotsos 2010 – Is it a Chicken, a Duck? No wait it’s Bob!

Bob Sneed being a hero and not to afraid to dance during the Hotsos Disco Night were others would chicken out…

marco's picture

Hotsos 2010 – Presenters, Presentations, Presenting

I never find it very easy to try to capture the atmosphere during a conference, the presenting part, the presentations or the discussions, for example, you could have with the presenters. Hotsos is such a cool and unique event were you have the opportunity, to listen but also to interact. The amount of people that attend isn’t that big, only a few hundreds, but they share all the same passion, the passion to improve on performance, mostly Oracle related. It has only two tracks and its not uncommon that people present and than go afterwards to a presentation to listen in what the other presenter has to say.

Due to the fact that it is manageable in terms of choice, located on a convenient location and well organized, you have the opportunity to pick just the thing you like and most of the time not miss out on “the other” presentation you would have liked to see. Besides that people stay in (overnight in the Hotel), so discussions about the technology, the method or an example during a presentation will be discussed in far more detail than you normally would do, from presenter to presenter or from presenter to the guy that attended and vice versa. The fact that all have the passion for performance or that they realize that performance is a beast with various angles to approach, bounds, and every point, every question is one to be heard and/or discussed. On equal terms. If you have seen my video impressions of Hotsos in 2009, you get a bit of what I am trying to say.

marco's picture

Hotsos 2010 – About swag, the Oscars and other stuff

Its Sunday and its raining outside. The nice weather on Saturday (approx. sunny / 20 degrees Celsius) has gone. After a decent flight on Friday where I actually made it to switch in Houston from the international Continental flight, going through customs and pick the next one, a domestic Continental Express flight, within the boundaries of 1 and 1/2 hour. I was so fast that switching for one flight to the other, that apparently my luggage didn’t manage to travel with the last flight. So after I found out that my luggage was still somewhere in Houston, I got from Dallas Love Field to the Omni Hotel in Las Colinas, Irving, where the Hotsos conference will be held again. The whole area is a bit in shambles because they are rebuilding a lot of the environment. While getting to the Grapevine Mills mall yesterday, I noticed that they also a building a new Irving Convention Center along the highway. Another addition to the already crowded Dallas/Plano/Irving Metroplex.

jkstill's picture

Who's using a database link?

Every once in awhile it is useful to find out which sessions are using a database link in an Oracle database. It's one of those things that you may not need very often, but when you do need it, it is usually rather important.

Unfortunately for those of us charged with the care and feeding of the Oracle RDBMS, this information is not terribly easy to track down.

marco's picture

Part of the Puzzle: Oracle XMLDB NFS Functionality

This story is long overdue and no its NOT about the Oracle Database 11g Database File System (DBFS). Its about an “undocumented” NFS functionality that, maybe someday, will be serviced by the XMLDB XDB Protocol Adapter. This post is “long overdue” because the actual attempts to try to figure it out were done during the bank holidays between X-mas and new year 2009.

So what is it all about. I once discovered in the Oracle 11gR1 documentation a small entry in the xmlconfig.xsd XML Schema regarding NFS elements that look like that they are or will be used for enabling NFS functionality based on the Oracle XMLDB Protocol Server architecture. In those days, when Oracle 11gR1 was just of the shelve, I made a few attempts, based on the xdbconfig.xsd XML Schema to adjust the corresponding xdbconfig.xml file that controls the XDB Protocol Server functionality, to see what would happen. At that time I only was able to get this far (see the picture) and I promised myself that I should look deeper into it trying to figure out if I could get it working and/or what the concepts were that made it tick in the XMLDB architecture but somewhere down the line I just didn’t come to it and it got “forgotten” by me due to my daily DBA workload.

NFS Protocol Server functionality enabled manually

Click picture to enlarge

harald's picture

Why does the size of my ORACLE_HOME increase?

Recently I discovered that the size of an ORACLE_HOME for a given release varies from machine to machine although the machines are of the same architecture and run the same operating system. A small difference in size can be explained by the fact that one ORACLE_HOME was re-linked in the past while the other wasn’t, […]

jkstill's picture

Cool but unknown RMAN feature

Unknown to me anyway until just this week.

Some time ago I read a post about RMAN on Oracle-L that detailed what seemed like a very good idea.

The poster's RMAN scripts were written so that the only connection while making backups was a local one using the control file only for the RMAN repository.

#eeeeee; border: 1px dashed rgb(153, 153, 153); color: black; font-family: Andale Mono,Lucida Console,Monaco,fixed,monospace; font-size: 12px; line-height: 14px; overflow: auto; padding: 5px; width: 100%;">rman target sys/manager nocatalog

After the backups were made, a connection was made to the RMAN catalog and a SYNC command was issued.

The reason for this was that if the catalog was unavailable for some reason, the backups would still succeed, which would not be the case with this command:

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