Troubleshooting

Nitin Singh,AAO/EDP,RTI Allahabad 1

Troubleshooting


Trace Files

Each server and background process can write to an associated trace file

When an internal error is detected by a process, it dumps information about the error to its trace file.

One special trace file is the ALERT file. It Keeps the information all internal errors (ORA-600), block corruption errors (ORA-1578), and deadlock errors (ORA-60) that occur


Administrative operations, such as CREATE/ALTER/DROP DATABASE/TABLESPACE/ROLLBACK SEGMENT SQL statements and STARTUP, SHUTDOWN, ARCHIVE LOG, and RECOVER SQL*DBA statementsSeveral messages and errors relating to the functions of shared server and dispatcher processesThe values of all initialization parameters when the database and instance start


Specifying the Location of Trace Files

All trace files for background processes and the ALERT file are written to the destination specified by the initialization parameter BACKGROUND_DUMP_DEST.

All trace files for server processes are written to the destination specified by the initialization parameter USER_DUMP_DEST


ORA-00604 error occurred at recursive SQL level num Cause:An error occurred while processing a recursive SQL statement (a statement applying to internal dictionary tables). Action: If the situation described in the next message on the stack can be corrected, do so; otherwise, contact Worldwide Customer Support.

Such problem is accompanied by some Secondary errors like ora-01652. Also this error with secondary error will be written to trace


Common Oracle Errors that DBA

face on day-to -day basis


ORA-01000 maximum open cursors exceeded

Cause: A host language program attempted to open too many cursors. The maximum number of cursors per user is determined by the initialization parameter OPEN_CURSORS.

Action: Modify the program to use fewer cursors. If this error occurs often, shut down ORACLE, increase the value of OPEN_CURSORS, and then restart ORACLE.

This problem is generally encountered in Pro *C programs ,VB,D2K applications etc change the OPEN_CURSORS parameter for init.ora file


ORA-01122 data file name - failed verification check

Cause:The information in the data file is inconsistent with information from the control file. This could

be because the control file is from a time earlier than the data files, or the data file size does not match the size specified in the control file, or the data file is

corrupted.

Action:Make certain that the data files and control files are the correct files for this database, then retry

the operation. This error is accompanied with other messages and are encountered during the startup of the Database. These errors are reported when we attempt to recover from a backup.


ORA-01545 rollback segment #'name' was not available Cause: Either: 1) A non-existent rollback segment was specified. 2) An instance tried to acquire a rollback segment that is in use or offline. 3) An attempt was made to drop a rollback segment that contains active transactions.

Action: Either: 1) Check spelling and specify a valid rollback segment name. If the name of the rollback segment to be changed is unknown, reopen the database and query the data dictionary for the names of existing rollback segments.


2) To start up an instance that tried to acquire this rollback segment, specify another rollback segment in the initialization parameter ROLLBACK_SEGMENTS or bring the tablespace containing the rollback segment online.

To drop a rollback segment that is in use, shut down the instance using it; or if it needs recovery, find out the errors that are preventing the rolling back of the transactions, and take appropriate actions.


By simply taking the rollback name from the ROLLBACK_SEGMENTS parameter we can start the Database.

Most probable reason is that the tablespace must be taken offline with IMMEDAITE option..


ORA-1652 to 1654

01652-- No More space for temporary segment01653-- No More space to allocate for table01654-- No More space to allocate index

01652 -00000, "unable to extend temp segment by %s in tablespace %s"// *Cause: Failed to allocate an extent for temp segment in tablespace.// *Action: Use ALTER TABLESPACE ADD DATAFILE statement to add one or more files to the tablespace indicated.


The ORA-165X error is possible the most encountered errors by the DBA’s. It provides 2 parameters SIZE and TABLESPACE_NAME

If the SYSTEM tablespace has space problem than this error will be accompanied by ORA-604


ORA-01628 max # of extents (number) reached for rollback segment number

Cause:An attempt was made to extend a rollback segment that already has reached its maximum size.

Action:If possible, increase the value of either the MAXEXTENTS or PCTINCREASE initialization parameters.

Related errors 163X 1630- for temp segment in tablespace1631- for extents in table1632- For extents in index


ORA-03113 end-of-file on communication channel This error is always followed by

ORA-03114 not connected to ORACLE Cause: A call to ORACLE was attempted when no connection was established. Usually this happens because a user-written program has not logged on. It may also happen if communication trouble causes a disconnection.

Action:Try again. If the message recurs and the program is user-written, check the program

For such type of errors Alert log on server should be looked into.


ORA-04031 Out of shared memory when trying to allocate num bytes(str)

Cause:More shared memory is needed than was allocated in the SGA.

Action:Reduce use of shared memory, or increase the amount of available shared memory byincreasing the value of the initializationparameter SHARED_POOL_SIZE.

Fragmentation of shared pool memory is common problem.This is faced when trying to load a big size packages,procedures so on.


ORA-01045 user name lacks CREATE SESSION privilege; logon denied

Cause:An attempt was made to connect to a userid that does not have create session privilege.

Action:If required, GRANT the user the CREATE SESSION privilege.

Connect as system and give the grants required


ORA-01950 no privileges on tablespace 'name'

Cause:The attempt to give the user a tablespace quota failed because the user does not have the necessary system privileges.

Action:Either grant the user the system privileges needed to create objects in the specified tablespace, or grant the user a specific space resource in the tablespace.

Alter user <username > quota 10M on <tbspnm>


SQL>Drop user username

ORA-01922 CASCADE must be specified to drop 'name'

Cause:The user owns objects that need to be dropped along with the user.

Action:Use the CASCADE command.

Use cascade to drop user and all objects owned by user permanently


Connectivity Errors

All connections to ORACLE on different computer require listener process running on the server

Example listener.ora and TNSnames.ora

Path is OS dependent usually located at $ORACLE_HOME/network/admin


12203, 00000, "TNS:unable to connect to destination"// *Cause: Invalid TNS address supplied or destination is not listening. This error can also occur because of underlying network transport// problems.// *Action: Verify that the service name you entered on the command line was correct. Ensure that the listener is running at the remote node and that the ADDRESS parameters specified in TNSNAMES.ORA are correct. Finally, check that all Interchanges needed to make the connection are up and running

Start listener on the Server


12154, 00000, "TNS:could not resolve service name"// *Cause: The service name specified is not defined correctly in the// TNSNAMES.ORA file. Enter/Update the entry for the SID for which connection is sought

12545, 00000, "Connect failed because target host or object does not exist"// *Cause: The address specified is not valid, or the program being connected to does not exist.

Update the host connection entry in the TCP/IP alias.


ERROR: ORA-12505: TNS:listener could not resolve SID given in connect descriptor

// *Action: Check to make sure that the SID specified is correct. The SIDs that are currently registered with the listener can be obtained by typing "LSNRCTL SERVICES <listener name>". These SIDs correspond to SID_NAMEs in TNSNAMES.ORA, or db_names in INIT.ORA.

// *Comment: This error will be returned if the database instance has not registered with the listener; the instance may need to be started.


12500, 00000, "TNS:listener failed to start a dedicated server process"// *Cause: The process of starting up a dedicated server process failed. The executable could not be found or the environment may be set up incorrectly.

This is a O/S error . Such problem arises only when the number of oracle sessions exhaust.In SCO Unix The increasing MAXUP process solves the problem

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Troubleshooting