How to update multiple rows using Hector

Is there a way I can update multiple rows in cassandra database using column family template like supply a list of keys. currently I am using updater columnFamilyTemplate to loop through a list of a keys and do an update for each row. I have seen queries like multigetSliceQuery but I don't know their equivalence in doing updates.

Solution

There is no utility method in ColumnFamilyTemplate that allow you to just pass a list of keys with a list of mutation in one call. You can implement your own using mutators.

This is the basic code on how to do it in hector

Set<String> keys = MY_KEYS;
Map<String, String> pairsOfNameValues = MY_MUTATION_BY_NAME_AND_VALUE;

Set<HColumn<String, String>> colums = new HashSet<HColumn<String,String>>();
for (Entry<String, String> pair : pairsOfNameValues.entrySet()) {
    colums.add(HFactory.createStringColumn(pair.getKey(), pair.getValue()));
}

Mutator<String> mutator = template.createMutator();
String column_family_name = template.getColumnFamily();
for (String key : keys) {
    for (HColumn<String, String> column : colums) {
        mutator.addInsertion(key, BASIC_COLUMN_FAMILY, column);
    }
}
mutator.execute();

Well it should look like that. This is an example for insertion, be sure to use the following methods for batch mutations:

mutator.addInsertion 
mutator.addDeletion
mutator.addCounter
mutator.addCounterDeletion

since this ones will execute right away without waiting for the mutator.execute():

mutator.incrementCounter
mutator.deleteCounter
mutator.insert
mutator.delete

As a last note: A mutator allows you to batch mutations on multiple rows on multiple column families at once ... which is why I generally prefer to use them instead of CF templates. I have a lot of denormalization for functionalities that use the "push-on-write" pattern of NoSQL.