Sql to create logical partitions

Question

Oracle: 10.2.0.5
I am working with another group and they are pulling data from one of the databases I work on. They are using what they call 'logical partitions'. Basically it is a sql statement with a MOD function in the where clause.
select *
from table
where mod(field,10) = 0This allows them to divide the table up into 10 chunks. So they run 10 sessions to pull data across the network. They are using array processing(1000 records at a time) in a 3rd party tool to pull the data and write it to teradata. I have no ability to change this process to something else. They are not using a cursor. its just a fetch of 1000 recorsd at a time. I checked that first.
The MOD function forces a full table scan. Before I go and and add a bunch of function based indexes to support this, does anyone know of another way to write these sqls without having to have a function on the left side of the where clause and get it to use an index? I want an index in part because 10 sessions is too slow to pull the data in an acceptable time so I want to increase the number of sessions i can handle. We are pulling from a number of tables so if its all full table scans I am far more constrained on my side.
I am hoping there is a way to on the fly chunk a table with buckets or something and use an index. So I can ramp this up to say 20-30 sessions per table so each session gets 1/20 or 1/30 of the table.

Answer 1

Guess2 wrote:
Oracle: 10.2.0.5
I am working with another group and they are pulling data from one of the databases I work on. They are using what they call 'logical partitions'. Basically it is a sql statement with a MOD function in the where clause.
select *
from table
where mod(field,10) = 0This allows them to divide the table up into 10 chunks. So they run 10 sessions to pull data across the network. They are using array processing(1000 records at a time) in a 3rd party tool to pull the data and write it to teradata. I have no ability to change this process to something else. They are not using a cursor. its just a fetch of 1000 recorsd at a time. I checked that first.
The MOD function forces a full table scan. Before I go and and add a bunch of function based indexes to support this, does anyone know of another way to write these sqls without having to have a function on the left side of the where clause and get it to use an index? I want an index in part because 10 sessions is too slow to pull the data in an acceptable time so I want to increase the number of sessions i can handle. We are pulling from a number of tables so if its all full table scans I am far more constrained on my side.
I am hoping there is a way to on the fly chunk a table with buckets or something and use an index. So I can ramp this up to say 20-30 sessions per table so each session gets 1/20 or 1/30 of the table.From the school of thought that if some is good, then more is better.
I suspect that the spindle upon which this table resides will be saturated
with I/O requests long before 20 is reached.
Session (CPU) is 100 - 1000 times faster than mechanical disk.
Sessions as few as a half dozen can overwhelm single disk drive.