HI JOE,
LASTLY i REDUCED THE SIZE OF SHARED_POOL WHICH WAS SET TO 230M TO 200M AND DB_BLOCK_BUFFERS TO 50000 WHICH WAS 60000 AND WATCHING FOR FURTHER HAPPENINGS,

IF THE PROBLEM STILL CONTINUES THEN i WILL LET U KNOW
AT U'R MAIL ADDRESS.

REGARDS AND THANKS

I AM READING IN THIS FORUM FROM LONG TIME TO SET SGA TO 30-40% OF MEMORY.BUT IN SOME BOOKS i FOUND SOMETHING ELSE,LIKE IF NO OTHER APPLICATION RUNNING IN SERVER I CAN SET SGA TO MORE THAN 50%.

WHAT DO U SAY?IN PREV VERSIONS OF ORACLE SOME VIEWS LIKE CURRENT_BUCKET AND RECENT_BUCKET WAS THERE TO FIND OUT THE NO. OF BLOCK BUFFERS NEEDED TO MAKE THE BUFFER HIT RATION >90%.IN VER 8.1.5 THEY R NOT THERE?HAVE U GOT ANY OTHER WAY TO FIND THE REQUIRED NO.OF BLOCK BUFFERS TO INCREASE HIT RATIO.OR JUST TO INCREASE AND CHECK THE RESULT.