Improvement of communication with external graphs

[chenejac]

Is your feature request related to a problem? Please describe. It looks performance in communication with external/remote graph bases is quite low. This task is to improve that.

Describe the solution you'd like

• [ ] The analysis of testing performance
• [ ] Conduct analysis of the code which might be bottle neck (time stamps for operations)
• [ ] Improve the performance

Additional context Testing performance analysis from DSpace community

• https://wiki.lyrasis.org/display/DSPACE/DSpace+7+Performance+Analysis

[chenejac]

Conclusions from discussion:

• We might try to speed up http communication by using some contemporary libraries
• Frequency of firing SPARQL queries should be optimized (all requested data for one page in one SPARQL query instead of many SPARQL queries)
• We might consider using Solr for fetching information in some cases