Below are the results of performance testing comparing performance of Fedora-based applications with real-world data.
Plum Ingest
Ingesting a large book with 1000 100MB TIFF images, repeated with Fedora 4.5.1 release (based on Modeshape 4), and the experimental Modeshape 5 branch (in both cases, Fedora was configured to use the PostgreSQL database object store). Durations are reported as HH:MM:SS, for batches of 100 images loaded using Princeton's Hydra head, Plum.
| Batch | Duration (Modeshape4) | Duration (Modeshape5) | Improvement |
|---|---|---|---|
| 1 | 0:19:19 | 0:13:52 | 28.2% |
| 2 | 0:27:03 | 0:23:19 | 13.8% |
| 3 | 0:39:16 | 0:33:41 | 14.2% |
| 4 | 0:52:13 | 0:43:43 | 16.3% |
| 5 | 1:06:22 | 0:56:36 | 14.7% |
| 6 | 1:23:29 | 1:10:46 | 15.2% |
| 7 | 1:41:26 | 1:26:30 | 14.7% |
| 8 | 2:02:22 | 1:43:08 | 15.7% |
| 9 | 3:17:40 | 2:37:31 | 20.3% |
| 10 | 3:47:48 | 3:10:14 | 16.5% |
Retrieving Objects With Many Links to Repository Objects
Compared to objects with a large number of literal properties or URI properties, objects with a large number of links to repository objects are much slower. E.g., an object with 10,000 properties where the objects are literals or non-repository URIs can be retrieved in 200 milliseconds, but an object with 10,000 properties where the objects are repository objects takes 7-36 seconds, depending on the settings, storage backend, etc.
There are also significant differences between LevelDB and PostgreSQL/MySQL backends, with LevelDB being much faster: 7-10 seconds as opposed to 29-36 seconds for the object with 10,000 links to repository objects.
| Version/Branch | LevelDB | MySQL | PostgreSQL |
|---|---|---|---|
| 4.5.0 | 8 | ||
| 4.5.1 | 10 | TODO | TODO |
| master (a58f5a05) | 7 | 32 | 29 |
| modeshape5 (c177adc8) | n/a | TODO | 30 |
| acoburn:fcrepo-1957 (4bf3ecab) | 9 | 36 | 30 |
See test scripts.
Testing initially focused on:
- using properties explicitly set on the object, as compared to IndirectContainers
- debugging the RDF-generation code that produces the IndirectContainer triples
- running under Tomcat instead of Jetty
However, those do not appear to significantly impact performance. So the process of converting a node reference to a URI seems like the most likely culprit (hence looking at acoburn:fcrepo-1957).
