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: Reducing sga_target in 10gR2 without getting ORA-00827

Schultz, Charles


We had significant problems with sga_target, enough that we finally
turned it off. Apparently, in there are some issues with the
algorithm that allocates/deallocates memory which can cause degradation.

Our Support Analyst(s) referenced the following bugs:
4466399/4472338 (dup) (SR 5386579.993): SYSTEM WIDE HANG ON MMON WAITING

Not sure if this is relevant for your situation, but wanted to offer it
up just in case.

-----Original Message-----
From: oracle-l-bounce@(protected)
Sent: Friday, June 16, 2006 9:31 AM
To: oracle-l@(protected)
Subject: Reducing sga_target in 10gR2 without getting ORA-00827

To attempt to mitigate ORA-04030 crashes we've been experiencing, Oracle
has suggested lowering sga_target. Unfortunately, the log/trace files
have provided no clues at all as to what is causing this crash every 3-5
weeks. The server has 4GB of physical RAM, but is not using the /3GB
switch so Oracle can only access 2GB. Currently sga_target is set at
1.2GB. The server runs only this 1 instance of Oracle so Windows has
plenty of mem.

select * from v$sga_dynamic_free_memory gives 0 because
sga_target=sga_max_size so Oracle has no memory to grow if needed. It
shouldn't need to since 1.2GB should be way more mem than it needs for

Based on note 295626.1 I don't think I can reduce sga_target appreciably
without getting ORA-00827 (could not shrink sga_target to specified
value). Currently the sum of the min sizes

(select component, current_size/1024/1024 "CURRENT_SIZE",
 min_size/1024/1024 "MIN_SIZE",
 user_specified_size/1024/1024 "USER_SPECIFIED_SIZE"
from v$sga_dynamic_components)

is 1188 and sga_target is 1200.

Is there any way I can reduce sga_target to 1000 dynamically? Will I
just have to keep doing it in small steps of 12 for example?


Michael Ray
Topshot Systems LLC