Jeff: I will poke around there, thanks. I love Objectify by the way - great
work.
I think one workaround might be to create a 'Sharded Index'. Let's say we
want to index a timestamp; we could do the following:
public void setTimestamp(Long timestamp) {
int shardNum= <well distributed numeric value in a defined range,either
randomly generated
or from existing variable>
this.shardedTimestamp= String.valueOf(shardNum) + String.valueOf(
timestamp);
}
public Long getTimestamp() {
return Long.parseLong(timestamp.substring(1));
}
When it comes time to query, we create a utility wrapper that creates
sharded queries. Something like this:
public class ShardedQuery<T>
{
int numberOfShards;
public List<Query<T>> queries;
public ShardedQuery(Query<T> q, int numberOfShards){
this.numberOfShards= numberOfShards;
this.queries= new ArrayList<Query<T>>(numberOfShards);
for(int i=0; i < numberOfShards; i++){
this.queries.add(q.clone());
}
}
public void addShardedFilter(String condition, String value){
for(int i=0; i < numberOfShards; i++){
String shardedVal= String.valueOf(i) + value;
this.queries.get(i).filter(condition, shardedVal);
}
}
public List<T> execute(){
List<QueryResultIterable<T>> iterables= new ArrayList<
QueryResultIterable<T>>(numberOfShards);
for(int i=0; i < numberOfShards; i++){
iterables.add(this.queries.get(i).fetch());
}
List<T> out= new LinkedList<T>();
for(QueryResultIterable<T> result : iterables){
for (T item : result){
out.add(item);
}
}
return out;
}
}
Actually, you could probably add something into Objectify to handle all
this for you.. perhaps create a '@ShardedIndex' annotation that would
automatically prepend a shardNum and split queries for you.
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