By A Web Design
- Category: Marketing on Big Data Blog
- Published on Tuesday, 25 October 2011 19:58
- Written by John Leach
- Hits: 879
A few challenges arise when querying HBase via JDO (Datanucleus) with indexes.
- Index Selection – We take into account fields in the case where there are only and operators and we allow tree traversal for multi-key indexes in the case there is an equals operator. We added special handling for startsWith since it helps us with front end search and sorting.
- Key Creation – The keys need to be multi-column, byte sortable, and searchable.
- Filter Creation – The filters need to be specialized to understand the index and implement a comparison of values. In essence, the index definition provides the typing for comparison.
- Paging – Based on sorting, the index, and the page size, Hbase needs to determine whether it can page or if the paging needs to pass to JDO.
- JDOQLEvaluator override – Does the JDOEvaluator need to filter the data, sort the data, or page the data? It depends on the index utilization cases.