Question

I have a Map, that I want to persist. The domain object is something like this:

public class Settings {
    private String key;
    private String value;

    public String getKey() { ... }
    public String getValue() { ... }
    public void setKey(String key) { ... }
    public void setValue(String value) { ... }
}

The standard approach is to generate a Setting for each pair, and saveOrUpdate() it. But it generates way too much queries, because I need to save lots of settings at a time, and it really affects perfomance. Is there a way to do this using one update query?

UPD: Okay, maybe there is a hql syntax for updating multiple rows? Something like

update Settings s1 set s1.value = :value1 where s1.key = :key1
                s2 set s2.value = :value2 where s2.key = :key2

Answer 1

If each setting is a row in a table then there needs to be as many update statements issued. But a few things to look at would be

1) Tweaking hibernate batch size to say 20 or so which means although hibernate issues 20 updates they are all sent as a batch (with hopefully one network round trip providing drivers permit batching)

2) Modifying your dao code/transaction logic to do things in batch

3) Having a stored procedure and passing array values (hibernate and storedprocs are not good friends I think)