[Mondrian] Issue with Cross Join 10 dimensions

Kurtis.Walker at thomsonreuters.com Kurtis.Walker at thomsonreuters.com
Wed Oct 20 09:03:34 EDT 2010


How many members are in each of your dimensions?  Are there values for
each intersection?  Mondrian has a couple of parameters you can set to
handle axes with high cardinality better,
mondrian.native.nonempty.enable and mondrian.native.crossjoin.enable.
Turning them on will enable Mondrian to evaluate the whole crossjoin
with a single SQL.  Caveat is the axis has to have "non empty"
specified.  Hope that helps.

 

Kurt

 

From: mondrian-bounces at pentaho.org [mailto:mondrian-bounces at pentaho.org]
On Behalf Of Venkatesh U
Sent: Wednesday, October 20, 2010 7:07 AM
To: mondrian at pentaho.org
Subject: [Mondrian] Issue with Cross Join 10 dimensions

 

Hi ,

  What I observed generally is it takes very longer when i try to do a
crossjoin with more than 7 dimensions. I am trying to run the below
query it runs for a very longer time 

select {
CrossJoin([Service].Members,CrossJoin([Product].Members,CrossJoin([Month
].Members,CrossJoin([TOD].Members,CrossJoin([IO].Members,[ForeignNetwork
].Members)))))
} on rows,
{[Measures].Members}
on columns
from [ServiceFactsByMonthWC]

Below is the tail of log file where mondrian is spending lot of time.
What is it doing? Is there any way to optimize cross joins? . I am
trying to use cross join as an option to prepopulate the Cube with a
single MDX query, so that the subsequent executions will be faster, is
there any better way to prepopulate the Cube, please let me know if
there are any,


DEBUG http-8080-4 mondrian.rolap.FastBatchingCellReader -
FastBatchingCellReader:
bitkey=0x000000000000000000000000000000000000000000000000000110101111000
0
  Service (4): "SERVICE_DIMENSION"."SERVICE_NAME"
  Product (5): "PRODUCT_DIMENSION"."PRODUCT_NAME"
  Year (6): "MONTH_DIMENSION"."CALENDER_YEAR"
  Quarter (7): "MONTH_DIMENSION"."CALENDER_QUARTER"
  Month (Key) (9): "MONTH_DIMENSION"."CALENDER_MONTH_NUMBER_IN_YEAR"
  IO (11): "INCOMING_OUTGOING_DIMENSION"."DIRECTION"
  ForeignNetworkName (12): "FOREIGN_NETWORK_DIMENSION"."FND_NAME"

DEBUG http-8080-4 mondrian.rolap.FastBatchingCellReader -
FastBatchingCellReader:
bitkey=0x000000000000000000000000000000000000000000000000000001101111000
0
  Service (4): "SERVICE_DIMENSION"."SERVICE_NAME"
  Product (5): "PRODUCT_DIMENSION"."PRODUCT_NAME"
  Year (6): "MONTH_DIMENSION"."CALENDER_YEAR"
  Quarter (7): "MONTH_DIMENSION"."CALENDER_QUARTER"
  Month (Key) (9): "MONTH_DIMENSION"."CALENDER_MONTH_NUMBER_IN_YEAR"
  TOD (10): "TIME_OF_DAY_DIMENSION"."TOD_NAME"

DEBUG http-8080-4 mondrian.rolap.FastBatchingCellReader -
FastBatchingCellReader:
bitkey=0x000000000000000000000000000000000000000000000000000101101111000
0
  Service (4): "SERVICE_DIMENSION"."SERVICE_NAME"
  Product (5): "PRODUCT_DIMENSION"."PRODUCT_NAME"
  Year (6): "MONTH_DIMENSION"."CALENDER_YEAR"
  Quarter (7): "MONTH_DIMENSION"."CALENDER_QUARTER"
  Month (Key) (9): "MONTH_DIMENSION"."CALENDER_MONTH_NUMBER_IN_YEAR"
  TOD (10): "TIME_OF_DAY_DIMENSION"."TOD_NAME"
  ForeignNetworkName (12): "FOREIGN_NETWORK_DIMENSION"."FND_NAME"

DEBUG http-8080-4 mondrian.rolap.FastBatchingCellReader -
FastBatchingCellReader:
bitkey=0x000000000000000000000000000000000000000000000000000011101111000
0
  Service (4): "SERVICE_DIMENSION"."SERVICE_NAME"
  Product (5): "PRODUCT_DIMENSION"."PRODUCT_NAME"
  Year (6): "MONTH_DIMENSION"."CALENDER_YEAR"
  Quarter (7): "MONTH_DIMENSION"."CALENDER_QUARTER"
  Month (Key) (9): "MONTH_DIMENSION"."CALENDER_MONTH_NUMBER_IN_YEAR"
  TOD (10): "TIME_OF_DAY_DIMENSION"."TOD_NAME"
  IO (11): "INCOMING_OUTGOING_DIMENSION"."DIRECTION"

DEBUG http-8080-4 mondrian.rolap.FastBatchingCellReader -
FastBatchingCellReader:
bitkey=0x000000000000000000000000000000000000000000000000000111101111000
0
  Service (4): "SERVICE_DIMENSION"."SERVICE_NAME"
  Product (5): "PRODUCT_DIMENSION"."PRODUCT_NAME"
  Year (6): "MONTH_DIMENSION"."CALENDER_YEAR"
  Quarter (7): "MONTH_DIMENSION"."CALENDER_QUARTER"
  Month (Key) (9): "MONTH_DIMENSION"."CALENDER_MONTH_NUMBER_IN_YEAR"
  TOD (10): "TIME_OF_DAY_DIMENSION"."TOD_NAME"
  IO (11): "INCOMING_OUTGOING_DIMENSION"."DIRECTION"
  ForeignNetworkName (12): "FOREIGN_NETWORK_DIMENSION"."FND_NAME"






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