Current HVR Bulk Refresh behavior for Oracle targets below Oracle 23 appears to have limited target-side slice parallelization compared to HVR Repair (row-wise) with slicing.

Based on benchmarking in our environment, HVR Bulk Refresh showed significantly lower throughput than HVR Repair (row-wise) when processing large sliced refresh workloads.

Observed benchmark results:

• Bulk Refresh

  • Table Size: ~10 GB

  • Duration: ~2 hours

  • Throughput: ~83 MB/min

• Bulk Refresh

  • Table Size: ~20 GB

  • Duration: ~8 hours

  • Throughput: ~42 MB/min

• Bulk Refresh with slicing (slicing count = 505)

  • Table Size: ~227 GB

  • Throughput: ~13.6 MB/min

  • Estimated Completion Time: ~9 days 11 hours

• HVR Repair (row-wise) with slicing (slicing count = 505) and a target-side index on the slicing column

  • Table Size: ~227 GB

  • Duration: ~28 hours

  • Throughput: ~133 MB/min

In our Oracle environment, HVR Repair (row-wise) with slicing achieved approximately 10x higher throughput than HVR Bulk Refresh for large tables.

Expected Enhancement

When slicing is enabled for Oracle targets, HVR Bulk Refresh should be enhanced to better utilize target-side parallelism and improve throughput for large-table refresh operations.

Possible implementation approaches may include:

• Parallel processing of slices on the Oracle target side.

• Alternative loading strategies when current bulk loading behavior limits slice parallelization.

• Improved scalability for large sliced refresh workloads.

Business Impact

Large Oracle refresh operations currently require using HVR Repair (row-wise) as a performance workaround, despite Bulk Refresh being the generally recommended refresh mechanism for large tables.

Improving Oracle Bulk Refresh performance would reduce refresh windows, improve operational efficiency, and provide a more consistent experience across Oracle target environments.

Environment:
CPU:
Thread(s) per core:  2
Core(s) per socket:  3
Socket(s):           2
RAM: 250GB
Oracle Version: 
Oracle Database 19c EE Extreme Perf Release 19.0.0.0.0 - Production
Version 19.24.0.0.0