[MADLIB-1342] Mini-batch preprocessor for images - performance issue

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: v1.17
• Component/s: Module: Utilities
• Assignee: Unassigned
• Reporter: Frank McQuillan
• Created: 13/May/19 17:44
• Updated: 12/Feb/20 19:35
• Resolved: 12/Feb/20 19:35

Description

Improve performance of mini-batch preprocessor for images. May involve writing a new matrix aggregation function to support multi-dimensional arrays.

I have a 2 segment GP5 cluster set up:

• preprocessing 50k training rows from CIFAR-10 fits into 3 buffers and takes ~1 hour (buffer size of 24415 is reported in the summary file) – i.e. used NULL buffer size

• preprocessing 10k training rows from CIFAR-10 fits into 1 buffer and takes ~2 minutes

More info:

If I use `buffer_size=5000` it takes 979 sec
If I use `buffer_size=500` it takes 75 sec

So I think there is an issue with large buffer sizes