Slow upload speed for large series

Hi all,
I have discovered a slow down in file loading that is dependent on the size of the dicom series.

I have discovered that load speeds are dependent on series size and get crippling slow at >20000 images in a series.

I tested on Orthanc 1.3 (also observed on 1.1 and 1.2), using postgresql plugin (index=true, storage=false) running on Linux Mint 18.1 (built following Ubuntu build notes and using static build).

I loaded three local studies (via python script, but also observed during push from MRI scanner), each with ~53000 images and watched the storage folder grow - see plot 1 (note doing a simple file count on the storage folder so showing 2x number of images). Obvious rapid loading and a period of very slow loading for each study.
I then repeated with one subject with the large study comprising 21000 images removed (plot 2) almost constant, rapid loading.
I then looked at the number of files in each series and the rate of loading (files per second) (plot 3 - results shown only for series > 100 images) and there is a clear trend of decrease in speed with increase in the number of images per series.

A study with 53528 images (single image dicoms) took 212 minutes to load to a local Orthanc instance. 195 mins of that time (92%) was spent loading a single series of 21600 images (41% of images).

Is this known/understood?

Obviously I would like the high speeds irrelevant of the series size.

Anything that I can modify in my setup to achieve this?

Note - obviously things like file size are to be considered also - but all “large series” presented here (>5000 images) are smaller individual files than other, faster loading, series.

Thanks for your help.


First of all, please make sure you compiled Orthanc and its associated plugins with the “-DCMAKE_BUILD_TYPE=Release” option while invoking CMake:


Thanks - yes have done this. Build commands tested were:




cmake …/OrthancPostgreSQL-2.0/ -DSTATIC_BUILD=ON -DCMAKE_BUILD_TYPE=Release

and in Config file:

“PostgreSQL” : {
“EnableIndex” : true,
“EnableStorage”: false,
“ConnectionUri” : “postgresql://localhost/orthanc?user=orthanc&password=orthanc”


As a consequence, you are most probably observing the following issues:


I see.
Thanks for the links.

Hi as a final update to this topic.
I have used a work around for this issue.
The large (20000+) file series is not needed in our server. It is for research only. So we deal with that separately and don’t import.

I appreciate the software, thanks for everyone’s efforts. I hope the MySQL implementation has not been completely shelved. Sorry we were not aware of it earlier.



Thanks for the feedback.

Regarding DB optimizations and MySQL support, be reassured that this is clearly still on our roadmap.