Calculating average time from two records from the same table.

Question

Hi all
I need to calculate the average time between two events that are recorded in the same table.
The table is TMS_MESSAGE_AUDIT_LOG
MESSAGE_ID VARCHAR2(16 BYTE) NOT NULL,
MESSAGE_VERSION NUMBER(2) NOT NULL,
CREATE_TM VARCHAR2(18 BYTE) NOT NULL,
MESSAGE_STATUS VARCHAR2(30 BYTE),
TRANSACTION_TYPE_NM VARCHAR2(30 BYTE),
MESSAGE_TP VARCHAR2(3 BYTE),
WORKFLOW_OBJECT VARCHAR2(30 BYTE) NOT NULL,
WORKFLOW_REQUEST VARCHAR2(30 BYTE) NOT NULL,
WORKFLOW_RETURN_CD VARCHAR2(30 BYTE) NOT NULL,
AUDIT_ACTION VARCHAR2(255 BYTE),
LAST_UPDATE_USER_LOGON_ID VARCHAR2(12 BYTE),
LOCAL_TM VARCHAR2(18 BYTE) NOT NULL,
LOCAL_TIME_ZN_NM VARCHAR2(70 BYTE) NOT NULL,
LOCAL_DAYLIGHT_IN CHAR(1 BYTE) NOT NULL,
FPRINT VARCHAR2(30 BYTE)
What i now need is
When the MESSAGE_ID is the same i need have the average time between when the MESSAGE_STATUS is AA and BB ( I need the time out of the CREATE_TM field )
And this for every 15 minutes interval.
Because this table will become BIG millions and millions of records it needs to be fast.
Can anybody help me.
Marcel

Answer 1

Something like this?
CREATE TABLE wr_test
( message_id                 VARCHAR2(16 BYTE) NOT NULL
, message_version            NUMBER(2) NOT NULL  -- Assumption: Acknowledged ver > Received ver
, create_tm                  VARCHAR2(18 BYTE) NOT NULL
, message_status             VARCHAR2(30 BYTE)
, transaction_type_nm        VARCHAR2(30 BYTE)
, workflow_object            VARCHAR2(30 BYTE) DEFAULT 'x' NOT NULL
, workflow_request           VARCHAR2(30 BYTE) DEFAULT 'x' NOT NULL
, workflow_return_cd         VARCHAR2(30 BYTE) DEFAULT 'x' NOT NULL
, audit_action               VARCHAR2(255 BYTE)
, last_update_user_logon_id  VARCHAR2(12 BYTE)
, local_tm                   VARCHAR2(18 BYTE) NOT NULL
, local_time_zn_nm           VARCHAR2(70 BYTE) DEFAULT 'GMT' NOT NULL
, local_daylight_in          CHAR(1 BYTE) DEFAULT 'x' NOT NULL );
INSERT ALL
INTO   wr_test
       ( message_id
       , message_version
       , create_tm
       , message_status
       , local_tm )
VALUES ( message_id
       , 1
       , create_tm
       , '(Receive)'
       , TO_CHAR(local_tm,'YYYYMMDD HH24:MI:SS') )
INTO   wr_test
       ( message_id
       , message_version
       , create_tm
       , message_status
       , local_tm )
VALUES ( message_id
       , 2
       , create_tm
       , 'Wait CLSB Ack'
     , TO_CHAR
       ( local_tm + NUMTODSINTERVAL(DBMS_RANDOM.VALUE(0,2e5),'SECOND')
       , 'YYYYMMDD HH24:MI:SS' ) )
SELECT ROWNUM AS message_id
     , TO_CHAR(SYSDATE,'YYYYMMDD HH24:MI:SS') AS create_tm
     , DATE '2000-01-01' + DBMS_RANDOM.VALUE(0,3) AS local_tm
FROM dual CONNECT BY ROWNUM < 100000;
WITH src AS
     ( SELECT message_id
            , message_status
            , message_version
            , TO_DATE(SUBSTR(local_tm,1,17),'YYYYMMDD HH24:MI:SS') AS dt
            , TO_DATE(SUBSTR(local_tm,1,8),'YYYYMMDD') AS dt_day
            , TO_CHAR(TO_DATE(SUBSTR(local_tm,10,8),'HH24:MI:SS'),'SSSSS') AS dt_sec
       FROM   wr_test
       WHERE  message_status IN ('(Receive)','Wait CLSB Ack') )
SELECT dt_day + NUMTODSINTERVAL(period,'SECOND') AS dt
     , NUMTODSINTERVAL(AVG(elapsed),'DAY') AS avg_elapsed
     , NUMTODSINTERVAL(MIN(elapsed),'DAY') AS min_elapsed
     , NUMTODSINTERVAL(MAX(elapsed),'DAY') AS max_elapsed
     , COUNT(*)
FROM   ( SELECT message_id
              , message_status
              , dt_day
              , TRUNC(dt_sec/300)*300 AS period
              , LEAD(dt) OVER (PARTITION BY message_id ORDER BY message_version) AS ack_dt
              , LEAD(dt) OVER (PARTITION BY message_id ORDER BY message_version) - dt AS elapsed
         FROM   src ) cal
WHERE  cal.message_status = '(Receive)'
GROUP BY dt_day, period
ORDER BY 1;Replace "wr_test" with "tms_message_audit_log" in the WITH subquery to test on your data.