 
pg_reorg can re-organize tables on a postgres database without any locks so that you can retrieve or update rows in tables being reorganized. The module is developed to be a better alternative of CLUSTER and VACUUM FULL.
Here shows the result of pg_reorg performance test. We have compared between non-fragmented table and fragmented table. Both tables have the same number of records, but fragmented table is bloated by UPDATEs.
 
| Category | Item | Details | 
|---|---|---|
| Hardware | CPU | Xeon E5645 2.4GHz (12 core) * 2 | 
| Memory | 32GB | |
| Storage | SAS 10,000rpm 2TB * 4 | |
| Software | OS | RHEL 6.2 (64bit) | 
| DB | PostgreSQL 9.3.4 | |
| pg_reorg | 1.1.10 | |
| Data | Scheme |  |