Oracle Database Discussions

Platform used : Oracle 11g.

Here is a simple fact table (with measures m1,m2) and dimensions (a) Location (b) Calendar and (c) Product. The business problem is that aggregation operator for measure m1,m2 are different along location dimension and Calendar dimension. The intention is to preaggregate the measures for a product along the calendar dimension and Location dimension and store it as materialized views.

The direct option is to define a materialized view with Inline queries (Because of the different aggrergation operator, it is not possible to write a query without Inline query). http://download-uk.oracle.com/docs/cd/B28359_01/server.111/b28313/qradv.htm#BABEAJBF documents the limitations that it works only for 'Text match' and 'Equivalent queries' and that is too limiting.

So decided to have nested materialized view, with first view having just joins(my_dim_mvw_joins), the second view having aggregations along Calendar dimension (my_dim_mvw_calendar) and third view having aggregations along the Location dimension(my_dim_mvw_location). Obviously I do not want the query I fire to know about materialized views and I fire it against the fact table. I see that for the fired query (Which needs aggregations along both Calendar and Location), is rewritten with just second materialized view but not the third. (Had set QUERY_REWRITE_INTEGRITY as TRUSTED) .

Wanted to know whether there are limitations on Query Writes with nested materialized views? Thanks

(Have given a simple testable example below. Pls ignore the values given in 'CALENDAR_IDs', 'PRODUCT_IDs' etc as they are the same for all the queries)

-- Calendar hierarchy table

CREATE TABLE CALENDAR_HIERARCHY_TREE
( "CALENDAR_ID" NUMBER(5,0) NOT NULL ENABLE,
"HIERARCHY1_ID" NUMBER(5,0),
"HIERARCHY2_ID" NUMBER(5,0),
"HIERARCHY3_ID" NUMBER(5,0),
"HIERARCHY4_ID" NUMBER(5,0),
CONSTRAINT "CALENDAR_HIERARCHY_TREE_PK" PRIMARY KEY ("CALENDAR_ID")
);

-- Location hierarchy table

CREATE TABLE LOCATION_HIERARCHY_TREE
( "LOCATION_ID" NUMBER(3,0) NOT NULL ENABLE,
"HIERARCHY1_ID" NUMBER(3,0),
"HIERARCHY2_ID" NUMBER(3,0),
"HIERARCHY3_ID" NUMBER(3,0),
"HIERARCHY4_ID" NUMBER(3,0),
CONSTRAINT "LOCATION_HIERARCHY_TREE_PK" PRIMARY KEY ("LOCATION_ID")
) ;

-- Product hierarchy table

CREATE TABLE PRODUCT_HIERARCHY_TREE
( "PRODUCT_ID" NUMBER(3,0) NOT NULL ENABLE,
"HIERARCHY1_ID" NUMBER(3,0),
"HIERARCHY2_ID" NUMBER(3,0),
"HIERARCHY3_ID" NUMBER(3,0),
"HIERARCHY4_ID" NUMBER(3,0),
"HIERARCHY5_ID" NUMBER(3,0),
"HIERARCHY6_ID" NUMBER(3,0),
CONSTRAINT "PRODUCT_HIERARCHY_TREE_PK" PRIMARY KEY ("PRODUCT_ID")
);

-- Fact table

CREATE TABLE RETAILER_SALES_TBL
( "PRODUCT_ID" NUMBER,
"PRODUCT_KEY" VARCHAR2(50 BYTE),
"PLAN_ID" NUMBER,
"PLAN_PERIOD_ID" NUMBER,
"PERIOD_ID" NUMBER(5,0),
"M1" NUMBER,
"M2" NUMBER,
"M3" NUMBER,
"M4" NUMBER,
"M5" NUMBER,
"M6" NUMBER,
"M7" NUMBER,
"M8" NUMBER,
"LOCATION_ID" NUMBER(3,0),
"M9" NUMBER,
CONSTRAINT "RETAILER_SALES_TBL_LOCATI_FK1" FOREIGN KEY ("LOCATION_ID")
REFERENCES LOCATION_HIERARCHY_TREE ("LOCATION_ID") ENABLE,
CONSTRAINT "RETAILER_SALES_TBL_PRODUC_FK1" FOREIGN KEY ("PRODUCT_ID")
REFERENCES PRODUCT_HIERARCHY_TREE ("PRODUCT_ID") ENABLE,
CONSTRAINT "RETAILER_SALES_TBL_CALEND_FK1" FOREIGN KEY ("PERIOD_ID")
REFERENCES CALENDAR_HIERARCHY_TREE ("CALENDAR_ID") ENABLE
);

-- Location dimension definition to promote query rewrite

create DIMENSION LOCATION_DIM
LEVEL CHAIN IS LOCATION_HIERARCHY_TREE.HIERARCHY1_ID
LEVEL CONSUMER_SEGMENT IS LOCATION_HIERARCHY_TREE.HIERARCHY3_ID
LEVEL STORE IS LOCATION_HIERARCHY_TREE.LOCATION_ID
LEVEL TRADING_AREA IS LOCATION_HIERARCHY_TREE.HIERARCHY2_ID
HIERARCHY PROD_ROLLUP (
STORE CHILD OF
CONSUMER_SEGMENT CHILD OF
TRADING_AREA CHILD OF
CHAIN
);

-- Calendar dimension definition

create DIMENSION CALENDAR_DIM
LEVEL MONTH IS CALENDAR_HIERARCHY_TREE.HIERARCHY3_ID
LEVEL QUARTER IS CALENDAR_HIERARCHY_TREE.HIERARCHY2_ID
LEVEL WEEK IS CALENDAR_HIERARCHY_TREE.CALENDAR_ID
LEVEL YEAR IS CALENDAR_HIERARCHY_TREE.HIERARCHY1_ID
HIERARCHY CALENDAR_ROLLUP (
WEEK CHILD OF
MONTH CHILD OF
QUARTER CHILD OF
YEAR
);

-- Materialized view with just joins needed for other views

CREATE MATERIALIZED VIEW my_dim_mvw_joins build immediate refresh complete enable query rewrite as
select product_id, lht.HIERARCHY1_ID, lht.HIERARCHY2_ID, lht.HIERARCHY3_ID, lht.location_id, cht.HIERARCHY1_ID year,
cht.HIERARCHY2_ID quarter, cht.HIERARCHY3_ID month, cht.calendar_id week, m1, m3, m7, m9
from retailer_sales_tbl RS, calendar_hierarchy_tree cht, location_hierarchy_tree lht
WHERE RS.period_id = cht.CALENDAR_ID
and RS.location_id = lht.location_id
and cht.CALENDAR_ID in (10,236,237,238,239,608,609,610,611,612,613,614,615,616,617,618,619,1426,1427,1428,1429,1430,1431,1432,1433,1434,1435,1436,1437,1438,1439,1440,1441,1442,1443,1444,1445,1446,1447,1448,1449,1450,1451,1452,1453,1454,1455,1456,1457,1458,1459,1460,1461,1462,1463,1464,1465,1466,1467,1468,1469,1470,1471,1472,1473,1474,1475,1476,1477)
AND product_id IN (5, 6, 7, 8, 11, 12, 13, 14, 17, 18, 19, 20)
AND lht.location_id IN (2, 3, 11, 12, 13, 14, 15, 4, 16, 17, 18, 19, 20)

-- Materialized view which aggregate along calendar dimension

CREATE MATERIALIZED VIEW my_dim_mvw_calendar build immediate refresh complete enable query rewrite as
select product_id, HIERARCHY1_ID , HIERARCHY2_ID , HIERARCHY3_ID ,location_id, year, quarter, month, week,
sum(m1) m1_total, sum(m3) m3_total, sum(m7) m7_total, sum(m9) m9_total,
GROUPING_ID(product_id, location_id, year, quarter, month, week) dim_mvw_gid
from my_dim_mvw_joins
GROUP BY product_id, HIERARCHY1_ID , HIERARCHY2_ID , HIERARCHY3_ID , location_id,
rollup (year, quarter, month, week);

-- Materialized view which aggregate along Location dimension

CREATE MATERIALIZED VIEW my_dim_mvw_location build immediate refresh complete enable query rewrite as
select product_id, year, quarter, month, week, HIERARCHY1_ID, HIERARCHY2_ID, HIERARCHY3_ID, location_id,
sum(m1_total) m1_total_1, sum(m3_total) m3_total_1, sum(m7_total) m7_total_1, sum(m9_total) m9_total_1,
GROUPING_ID(product_id, HIERARCHY1_ID, HIERARCHY2_ID, HIERARCHY3_ID, location_id, year, quarter, month, week) dim_mvw_gid
from my_dim_mvw_calendar
GROUP BY product_id, year, quarter, month, week,
rollup (HIERARCHY1_ID, HIERARCHY2_ID, HIERARCHY3_ID, location_id)


-- SQL Query Fired (for simplicity have used SUM as aggregation operator for both, but they will be different)

select product_id, year, HIERARCHY1_ID, HIERARCHY2_ID,
sum(m1_total) m1_total_1, sum(m3_total) m3_total_1, sum(m7_total) m7_total_1, sum(m9_total) m9_total_1
from
(
select product_id, HIERARCHY1_ID , HIERARCHY2_ID , year,
sum(m1) m1_total, sum(m3) m3_total, sum(m7) m7_total, sum(m9) m9_total
from
(
select product_id, lht.HIERARCHY1_ID , lht.HIERARCHY2_ID , lht.HIERARCHY3_ID ,lht.location_id, cht.HIERARCHY1_ID year, cht.HIERARCHY2_ID quarter, cht.HIERARCHY3_ID month, cht.calendar_id week,m1,m3,m7,m9
from
retailer_sales_tbl RS, calendar_hierarchy_tree cht, location_hierarchy_tree lht
WHERE RS.period_id = cht.CALENDAR_ID
and RS.location_id = lht.location_id
and cht.CALENDAR_ID in (10,236,237,238,239,608,609,610,611,612,613,614,615,616,617,618,619,1426,1427,1428,1429,1430,1431,1432,1433,1434,1435,1436,1437,1438,1439,1440,1441,1442,1443,1444,1445,1446,1447,1448,1449,1450,1451,1452,1453,1454,1455,1456,1457,1458,1459,1460,1461,1462,1463,1464,1465,1466,1467,1468,1469,1470,1471,1472,1473,1474,1475,1476,1477)
AND product_id IN (5, 6, 7, 8, 11, 12, 13, 14, 17, 18, 19, 20)
AND lht.location_id IN (2, 3, 11, 12, 13, 14, 15, 4, 16, 17, 18, 19, 20)
)
GROUP BY product_id, HIERARCHY1_ID , HIERARCHY2_ID , HIERARCHY3_ID , location_id, year
) sales_time
GROUP BY product_id, year,HIERARCHY1_ID, HIERARCHY2_ID

This Query rewrites only with my_dim_mvw_calendar. (as saw in Query Plan and EXPLAIN_MVIEW). But we would like it to use my_dim_mvw_location as that has aggregations for both dimensions.