ORA-02085 I created a database link without any problem. But when I tried to test the link, I got ORA-02085. SQL> select sysdate from dual@source_link; select sysdate from dual@source_link * ERROR at line 1: ORA-02085: database link SOURCE_LINK connects to SOURCE_DATABASE Let’s see […]
UNDO_RETENTION At times, you may find out or feel that UNDO_RETENTION is useless at all. Raising the number of seconds cannot resolve ORA-01555. This is true under some specific conditions. Here I quote the requisites from the official document below: Fix-sized Undo Tablespace The UNDO_RETENTION parameter is ignored for a fixed size undo tablespace. The […]
DBAs usually set PROCESSES when initializing a new database:SQL> alter system set processes=3000 scope=both;System altered.Another important parameter SESSIONS will be derived from PROCESSES automatically in this manner:SESSIONS = (1.5 * PROCESSES) + 22In a dedicated server environment, the derived value of SESSIONS could be somewhat close to the facts of database. You can accept the value […]
If you are planning to install additional database by DBCA on a Linux server, you should notice not only the limitation of semaphores, but also the limitation of the shared memory, otherwise, you might see ORA-00845 like the following when trying to startup the second database after the first one is online:SQL> startup;ORA-00845: MEMORY_TARGET not […]
BYTE vs CHAR in NLS_LENGTH_SEMANTICS Most of databases set NLS_LENGTH_SEMANTICS as BYTE by default, but there are some databases in Non-English country will take CHAR as the default unit of data type for CHAR and VARCHAR2.
When you ALTER SYSTEM to modify an initialization parameter, it sometimes fails with ORA-02097 ORA-02097: parameter cannot be modified because specified value is invalid Reproduce ORA-02097 Let’s me show you some examples that can reproduce ORA-02097 and I will explain it more detailed along with the context. Here I would like to change DB_RECOVERY_FILE_DEST location. […]
For a RAC database, we may want to archive the redo logs to local destinations of instances rather than ASM. That is, put instance #1, #2 archive thread #1, #2 redo logs to their respective local destinations. To achieve this goal, LOG_ARCHIVE_DEST_1 should be setup more granularly by sid like this way:SQL> alter system set log_archive_dest_1=’location=/oracle/oradata/arch1′ […]
A misconfigured database is a database which was set with wrong values of initialization parameters in SPFILE, it will prevent the database from startup. Let’s see a typical example that can reproduce the problem: Reproducing ORA-00837 We are trying to change MEMORY_TARGET. First of all, we should check the original value. SQL> show parameter memory […]