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TNS:could not resolve the connect identifier specified
Backtrace message unwound by exceptions
invalid identifier
PL/SQL compilation error
internal error
missing expression
table or view does not exist
end-of-file on communication channel
TNS:listener unknown in connect descriptor
insufficient privileges
PL/SQL: numeric or value error string
TNS:protocol adapter error
ORACLE not available
target host or object does not exist
invalid number
unable to allocate string bytes of shared memory
resource busy and acquire with NOWAIT specified
error occurred at recursive SQL level string
ORACLE initialization or shutdown in progress
archiver error. Connect internal only, until freed
snapshot too old
unable to extend temp segment by string in tablespace
Credential retrieval failed
missing or invalid option
invalid username/password; logon denied
unable to create INITIAL extent for segment
out of process memory when trying to allocate string bytes
shared memory realm does not exist
cannot insert NULL
TNS:unable to connect to destination
remote database not found ora-02019
exception encountered: core dump
inconsistent datatypes
no data found
TNS:operation timed out
PL/SQL: could not find program
existing state of packages has been discarded
maximum number of processes exceeded
error signaled in parallel query server
ORACLE instance terminated. Disconnection forced
TNS:packet writer failure
see ORA-12699
missing right parenthesis
name is already used by an existing object
cannot identify/lock data file
invalid file operation
quoted string not properly terminated

Re: unix - calc file descriptors

Gogala, Mladen

2005-07-12

Replies:
Sean Hull wrote:

>I'm wondering how to calculate the number of file descriptors Oracle will
>use on Unix. Obviously there will be one file descriptor for each file,
>and for each socket (connection through listener). How about for IPC
>connections? How about for Oracle processes (oracle executable file)?
>I'm assuming device files aren't counted, as the OS or root user has those
>mounted & open.
>
>Perhaps someone could point me to a document, or metalink reference which
>details this.
>
>
>
Sean, the best document I can point you to is here:
http://publib.boulder.ibm.com/infocenter/ids9help/index.jsp?topic=/com.ibm.perf.doc/perf02.htm

Be warned, this is the publication about tuning the Great Enemy of
Oracle Corp, the UDB (DB2) database.
On modern Unix boxes, the file descriptor table is dynamic and the
number of file descriptors is set
per process, with setrusage based mechanisms and configuration files
(/etc/security/limits.conf on RH Linux)
My experience is that if I set it to 2048 file descriptors per process,
it will not create any problems for me.
Kernel file descriptor table is dynamic and, normally, you can not limit
it. Per process descriptor table is
a table of pointers, which contain integer offset to the system open
inode table (each file is an inode). So, if you
set 2048 open file descriptors per process on a 64 bit machine you will
increase the address space for 8kb.
On a database server which typically has memory measured in gigabytes,
8k per process is not worth mentioning.
May the force be with you.

--
Mladen Gogala
Oracle DBA
Ext. 121


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