Interested to Buy Any Domain ? << Click Here >> for more details...
What is the difference between lookup and sparse lookup?
- 1 Answers
- 6793 Views
- I also Faced
- E-Mail Answers
Answer Posted / subhash
Normal lookup will provide data for an in-memory look up
whereas Sparse lookup will access the database directly.
Normal might provide poor performance when the reference
data is huge as it has to load large data into memory.
In such scenarios a join stage may work better(It will put
the data onto an internal dataset file for each link,
and then do the join based on the data provided). If your
stream/source data is small then a sparse lookup is
suggested
as a row is retrieved from the database for each input row
instead of the full reference data being brought into
memory.
Sparse lookup sends individual SQL statement for every
incoming row (If stream/source data is huge you can imagine
the number
of times it has to hit DB and hence the down side on
performance). It can be used when you want to get the next
sequence
number from your database (Again expensive overhead on your
job as noted before). Also note that sparse lookup is only
available for DB2 and Oracle. Normal Lookup stage can have
multiple reference link but Sparse can only have one
reference
link. When normal is used it is a good practice to choose
less volume data as reference data.
| Is This Answer Correct ? | 15 Yes | 1 No |
Post New Answer View All Answers
sed,awk,head
What is the Environment Variable need to Set to TRIM in Project Level?(In transfermer, we TRIM function but I need to impliment this project level using Environment variable)
Can you filter data in hashed file?
How many Key we can define in remove duplicate stage?
What is the difference between in process and inter process?
What are the differences between datastage and informatica?
What are the features of datastage flow designer?
Differentiate between hash file and sequential file?
tell me 5 situations when we r using oracle db stages like orecle connector, oracle enterprise
Explain ibm infosphere information server and highlight its main features?
explain about completely flow of sequencers technicaly,without using example??explain about lookup,nullhandling?
Why do you need stage variables?
which r the connectors used in san?
if i have two tables table1 table2 1a 1a,b,c,d 1b 2a,b,c,d,e 1c 1d 2a 2b 2c 2d 2e how can i get data as same as in tables? how can i implement scd typ1 and type2 in both server and in parallel? field1 field2 field3 suresh , 10,324 , 355 , 1234 ram , 23,456 , 450 , 456 balu ,40,346,23 , 275, 5678 how to remove the duplicate rows,inthe fields?
What is the difference between server job and parallel jobs?
