All Oracle Error Codes
Oracle DBA Forum

Frequent Oracle Errors

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: can't connect '/ as sysdba'

Janine Sisk


I finally found the problem.

I ran strace as several of you suggested. It didn't show anything
obvious failing, but it did show that sqlplus was reading sqlnet.ora
as part of the authentication process. The contents of that file were:


which looked ok to me, but this is not an area I'm expert in. So I
tried moving that file to a new name, to see what would happen if it
wasn't found.

I found that sqlplus was now reading a file called .sqlnet.ora (that
starts with a dot) that lives in the oracle user's home directory.  
That file looked like this:


Hmm... this looks like a leftover from another time, when the system
was used as a client for Oracle running on another server. So I
moved this file to another name, and presto - sqlplus '/ as sysdba'
started working. So I put the regular sqlnet.ora file back in place,
and it still works.

Here's the thing I don't get: the dot-sqlnet.ora file was not being
opened every time the thing failed. I have grepped for it in my
various trace output files and it was opened whenever sqlnet.ora
could not be found or if the listener was down. But it was not
opened if the listener was up and sqlnet.ora was in place, and yet
it's presence was still causing authentication to fail.

The only thing I can gather is that the presence of that file
influenced the starting up of the listener too, and therefore how or
where sqlplus was looking to authenticate.

Thanks for all the helpful suggestions!