blog

CPU bound queries

Tue, 15 Jan 2013 23:38:31 +0100

This can be used to find queries that use CPU heavily. It starts by determining a baseline and then identifies those queries that use more CPU than the baseline * an arbitrary multiplier. If you want to use this in a balanced RAC environment change the references to v$sqlarea to gv$sqlarea. Functions are used to return topCPU and user to the mainline.

SET SERVEROUTPUT ON SIZE 1000000

DECLARE

topCPUkount                 NUMBER;
multiplier                  NUMBER     := .60;

CURSOR cpuCursor (cKount NUMBER) IS
SELECT *
    FROM v$sqlarea
   WHERE cpu_time > cKount;

FUNCTION topCPU RETURN NUMBER IS
num NUMBER;
BEGIN
SELECT MAX(cpu_time)
    INTO num
    FROM v$sqlarea;
RETURN num;
EXCEPTION
WHEN OTHERS THEN
    dbms_output.put_line(SQLERRM);
END;

FUNCTION getUser(uid    NUMBER) RETURN VARCHAR2 IS
str VARCHAR2(30);
BEGIN
SELECT username
    INTO str
    FROM dba_users
   WHERE user_id = uid;
RETURN str;
EXCEPTION
WHEN OTHERS THEN
    dbms_output.put_line(SQLERRM);
END;

BEGIN
topCPUkount := topCPU;
dbms_output.put_line('Top CPU Count = '||topCPUkount);
FOR i IN cpuCursor (topCPUkount * multiplier) LOOP
    dbms_output.put_line('--------');
    dbms_output.put_line('Last Active = '||TO_CHAR(i.last_active_time,'YYYY-MM-DD HH:MI'));
    dbms_output.put_line(getUser(i.parsing_user_id));
    dbms_output.put_line(i.sql_text);
END LOOP;

EXCEPTION
WHEN OTHERS THEN
    dbms_output.put_line(SQLERRM);
END;

Check for Locked objects

Mon, 16 May 2011 13:13:44 +0100

A handy script to check for locked objects in a database.

SET SERVEROUTPUT ON SIZE 1000000

DECLARE

kount           NUMBER   := 0;
objectName dba_objects.object_name%TYPE;
objectType dba_objects.object_type%TYPE;
schemaOwner dba_objects.owner%TYPE;

CURSOR lock_cursor IS
SELECT *
    FROM gv$locked_object;

BEGIN
FOR i IN lock_cursor LOOP
    kount := kount + 1;
    SELECT owner,object_name,object_type
      INTO schemaOwner,objectName,objectType
      FROM dba_objects
     WHERE object_id = i.object_id;
   dbms_output.put_line(i.inst_id||'    '||RPAD(schemaOwner,20)||' ' || objectName ||' '||objectType);
END LOOP;
   dbms_output.put_line('Locked Object Count = '||kount);
EXCEPTION
WHEN OTHERS THEN
    dbms_output.put_line(SQLERRM);
END;
/

Check Oracle Tablespace Size

Mon, 16 May 2011 12:49:50 +0100

A useful script for checking the size of tablespaces

SET PAGESIZE 100

COL "Tablespace" FOR a22
COL "Used MB" FOR 99,999,999
COL "Free MB" FOR 99,999,999
COL "Total MB" FOR 99,999,999

SELECT df.tablespace_name "Tablespace",
       totalusedspace "Used MB",
       (df.totalspace - tu.totalusedspace) "Free MB",
        df.totalspace "Total MB",
        round(100 * ( (df.totalspace - tu.totalusedspace)/ df.totalspace)) "Pct. Free"
FROM
    (SELECT tablespace_name,
            round(sum(bytes) / 1048576) TotalSpace
       FROM dba_data_files
       GROUP BY tablespace_name) df,
                (select round(sum(bytes)/(1024*1024)) totalusedspace, tablespace_name
        FROM dba_segments
       GROUP BY tablespace_name) tu
WHERE df.tablespace_name = tu.tablespace_name
ORDER BY df.tablespace_name