DBA Tips Archive for Oracle


What is the purpose of the sgadef.dbf file?

by Jeff Hunter, Sr. Database Administrator

The sgadef.dbf file can be found in the ${ORACLE_HOME}/dbs directory. It is important to remember that you CANNOT remove this file. It tells the oracle shadow process the address of the SGA when the process first connects to the database. If the process cannot find this file, it assumes the database is down.

Problems can arise when the reverse is true. (ie. the database is down but the sgadef file exists) This can happen when the system crashes. In this case, the memory segment addressed in the file doesn't exist which results in an error. (try ipcs -m to convince yourself)

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Last modified on
Saturday, 03-Jul-1999 00:00:00 EDT
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