Recommendation on ID indexes about cqengine HOT 1 CLOSED

Hi Sandeep, this belongs more in the forum than as an issue.

Have you tried IndexQuantization? This is a good way to reduce memory usage.

Also are your ID values sparse? If so you could write your own quantizer to 
better handle sparse values, like this one:

/**
 * Converts sparse double values, to a fixed number of buckets.
 * <p/>
 * This quantizer should only be used with equality-based indexes, such as {@code HashIndex}.
 */
public class SparseDoubleQuantizer implements Quantizer<Double> {
    private final int numBuckets;
    public SparseDoubleQuantizer(int numBuckets) {
        this.numBuckets = numBuckets;
    }
    @Override
    public Double getQuantizedValue(Double attributeValue) {
        return (double) attributeValue.longValue() % numBuckets;
    }
}

The quantizer above will restrict the size of an equality-based index (e.g. 
HashIndex) to a fixed number of buckets, independent of the number of unique 
values of your IDs. But it cannot be used with a NavigableIndex.

This is not the best place to answer questions. If you like post your question 
in the forum http://groups.google.com/group/cqengine-discuss and we can 
continue discussion there. thanks!