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Databases

Posted by Alan Chen
Alan Chen
1,351 Points

Performing many queries in a single Hibernate session

Is it dangerous to perform hundreds to thousands of queries within a single Hibernate session?

I am reading an excel file that can have rows on the order of tens of thousands and I need to insert its information into a database. Right now I am reading the rows of the excel file into Java objects that I am storing in a List. I am then opening a Hibernate session and starting a transaction and iterating through the list, inserting each object one by one.

I have other methods that split up the list into chunks on the order of hundreds and then creating separate sessions/transactions for each of those chunks.

Should I be splitting the list up or does it not matter?

1 Answer

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

The "danger" might be loss of time on error.

I like doing time-intensive operations in smaller chunks because if an error occurs, you don't have to restart the entire thing from scratch.

Alan Chen
Alan Chen
1,351 Points

I understand splitting the operation into multiple transactions, but should I split it into multiple sessions (high overhead)? Is there a common practice for how to handle potentially long connections with databases?

Update: I read about batch processing https://docs.jboss.org/hibernate/orm/4.0/devguide/en-US/html/ch04.html and it seems like this is a possible solution to saving large sets of data.

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

Batch processing is great to offset reliance on maintaining a connection for an extended time, but I'd still recommend processing in chunks for the same reason (to reduce recover time from errors).