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What leads to server crash? [message #339393] Thu, 07 August 2008 07:27 Go to next message
Suwarna
Messages: 10
Registered: August 2008
Location: Mumbai
Junior Member
Hello,

Just wanted to know what kind of queries can lead to server crash... and how do we come to know that it has crashed?...

will doing 'explain plan' before firing the query be a good precaution?.. i am new to oracle and it would be great if there were some suggestions on what to do after such a crash.

thanks
Re: What leads to server crash? [message #339403 is a reply to message #339393] Thu, 07 August 2008 07:39 Go to previous messageGo to next message
Frank
Messages: 7880
Registered: March 2000
Senior Member
What makes you think that executing a query can make your server crash?
Re: What leads to server crash? [message #339409 is a reply to message #339403] Thu, 07 August 2008 07:56 Go to previous messageGo to next message
tahpush
Messages: 961
Registered: August 2006
Location: Stockholm/Sweden
Senior Member

Quote:
and how do we come to know that it has crashed?

By all the phone-calls made by angry users
Re: What leads to server crash? [message #339444 is a reply to message #339409] Thu, 07 August 2008 09:09 Go to previous messageGo to next message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
Or the muffled screams from the server room as the DBA's notice.

Re: What leads to server crash? [message #339445 is a reply to message #339409] Thu, 07 August 2008 09:11 Go to previous messageGo to next message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
After a crash, you let someone who knows what he's doing investigate the cause of the crash, and restart/restore & recover the database.

Doing an explain plan will have no effect at all on the liklihood of the server coming down.
Re: What leads to server crash? [message #339446 is a reply to message #339393] Thu, 07 August 2008 09:14 Go to previous messageGo to next message
BlackSwan
Messages: 25046
Registered: January 2009
Location: SoCal
Senior Member
In recalling my experiences with servers crashing,
the last I can recall was Solaris 7 running Oracle V7.3.4.5 about 15 years ago.
Operating systems have much improved since then.

Still today Oracle session will occasionally core dump, but for me those are few & far between.
Re: What leads to server crash? [message #339447 is a reply to message #339444] Thu, 07 August 2008 09:16 Go to previous messageGo to next message
tahpush
Messages: 961
Registered: August 2006
Location: Stockholm/Sweden
Senior Member

JRowbottom wrote on Thu, 07 August 2008 16:09
Or the muffled screams from the server room as the DBA's notice.



A new word to my english vocabulary - "muffled"
Smile
Re: What leads to server crash? [message #339450 is a reply to message #339446] Thu, 07 August 2008 09:21 Go to previous messageGo to next message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
I had to take the server out from underneath an 8i instance a couple of times.
The client had a lovingly handcrafted Dll that they were calling via Extproc, and it would occasionally crash while holding a lot of locks, and not respond to Kill session commands.
It actually left the database in such a state that a Shutdown Abort wouldn't take it down.

Re: What leads to server crash? [message #339452 is a reply to message #339447] Thu, 07 August 2008 09:22 Go to previous messageGo to next message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
If you stand near DBA's after crashing their Database, you'll probably learn some other new words.... Cool
Re: What leads to server crash? [message #339607 is a reply to message #339393] Thu, 07 August 2008 22:52 Go to previous messageGo to next message
Suwarna
Messages: 10
Registered: August 2008
Location: Mumbai
Junior Member
well,

What i meant was...
wat if we write a code such as -

while x<10
loop
insert into tempp values (x,'in while loop');
x:=x+1
end loop

Now,if we omit the condition x:=x+1, the program goes into an infinite loop..inserting values into tempp, hence occupying the entire HDD and leading to server failure...

pls post your thoughts.. am i thinking rite?.

P.S My apologies for the unformatted code .. its just a snippet i havent tried out..
Re: What leads to server crash? [message #339610 is a reply to message #339393] Thu, 07 August 2008 23:19 Go to previous messageGo to next message
BlackSwan
Messages: 25046
Registered: January 2009
Location: SoCal
Senior Member
>am i thinking rite?.
You might be able to shoot yourself in the foot & do something as brain dead foolish in your post on YOUR system, but
it would not occur in 99.999% actual Production systems.

Tablespaces on in my database can not fill up the disk.
Even if a volume fills up, neither OS nor Oracle will crash.
The application may start spewing errors, but both Oracle & the OS remain online to report difficulties.

Assuming you are running supported configurations, "crashes" no longer occur.
One flavor of problems can still impact organization & they are hardware failures. The use of redundant SAN & clusters can effectively provide 24x365 application availability.

Simply put, with proper design & engineering, downtime can be effectively eliminated.

Your concerns were justified a decade ago, but are history today.
Re: What leads to server crash? [message #339612 is a reply to message #339393] Thu, 07 August 2008 23:35 Go to previous message
Suwarna
Messages: 10
Registered: August 2008
Location: Mumbai
Junior Member
Thank you. since i am new , I did not know...
anyway...now on will look for answers elsewhere first, so that as a beginner I donot sound too naive...
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