Hi,

Hibernate:
8.2.6.ga
Database:
postgres and oracle


I have to read data from the oracle-database (legacy), do some stuff with the data and then insert it into the postgres-database.

however there is a lot of data (over a million rows with over 20 columns) and i dont want to hold all of the data in memory.

how can i partially read data from the oracle-database (e.g. 1000 rows each iteration)?
does the query-iterator fetch each row separately or does it load the whole data into memory and then iterate over it?

i dont want to do something like
select * where id between 1000 and 2000
because the ids are not really consecutively, there migth be only one row between id 101.000 and 102.000..

//ecit
is pagination the right answer?
like discussed here: http://forum.springframework.org/showthread.php?t=9658

Somtimes, when you're deaing with such a large number of rows, hibernate isn't necessarily the answer.

Perhaps, in a case like this, you might want to consider ETL tools like DataStage or something along those lines?