Display database SGA statistics

DECLARE
libcac NUMBER(10,2);
rowcac NUMBER(10,2);
bufcac NUMBER(10,2);
redlog NUMBER(10,2);
spsize NUMBER;
blkbuf NUMBER;
logbuf NUMBER;
BEGIN
SELECT VALUE INTO redlog FROM v$sysstat
WHERE name = 'redo log space requests';
SELECT 100*(SUM(pins)-SUM(reloads))/SUM(pins) INTO libcac FROM v$librarycache;
SELECT 100*(SUM(gets)-SUM(getmisses))/SUM(gets) INTO rowcac FROM v$rowcache;
SELECT 100*(cur.VALUE + con.VALUE - phys.VALUE)/(cur.VALUE + con.VALUE) INTO bufcac
FROM v$sysstat cur,v$sysstat con,v$sysstat phys,v$statname ncu,v$statname nco,v$statname nph
WHERE cur.statistic# = ncu.statistic#
AND ncu.name = 'db block gets'
AND con.statistic# = nco.statistic#
AND nco.name = 'consistent gets'
AND phys.statistic# = nph.statistic#
AND nph.name = 'physical reads';
SELECT VALUE INTO spsize FROM v$parameter WHERE name = 'shared_pool_size';
SELECT VALUE INTO blkbuf FROM v$parameter WHERE name = 'db_block_buffers';
SELECT VALUE INTO logbuf FROM v$parameter WHERE name = 'log_buffer';
DBMS_OUTPUT.put_line('> SGA CACHE STATISTICS');
DBMS_OUTPUT.put_line('> ********************');
DBMS_OUTPUT.put_line('> SQL Cache Hit rate = '||libcac);
DBMS_OUTPUT.put_line('> Dict Cache Hit rate = '||rowcac);
DBMS_OUTPUT.put_line('> Buffer Cache Hit rate = '||bufcac);
DBMS_OUTPUT.put_line('> Redo Log space requests = '||redlog);
DBMS_OUTPUT.put_line('> ');
DBMS_OUTPUT.put_line('> INIT.ORA SETTING');
DBMS_OUTPUT.put_line('> ****************');
DBMS_OUTPUT.put_line('> Shared Pool Size = '||spsize||' Bytes');
DBMS_OUTPUT.put_line('> DB Block Buffer = '||blkbuf||' Blocks');
DBMS_OUTPUT.put_line('> Log Buffer = '||logbuf||' Bytes');
DBMS_OUTPUT.put_line('> ');
IF
libcac < 99 THEN DBMS_OUTPUT.put_line
('*** HINT: Library Cache too low! Increase the Shared Pool Size.');
END IF;
IF
rowcac < 85 THEN DBMS_OUTPUT.put_line
('*** HINT: Row Cache too low! Increase the Shared Pool Size.');
END IF;
IF
bufcac < 90 THEN DBMS_OUTPUT.put_line
('*** HINT: Buffer Cache too low! Increase the DB Block Buffer value.');
END IF;
IF
redlog > 100 THEN DBMS_OUTPUT.put_line
('*** HINT: Log Buffer value is rather low!');
END IF;
END;
/