How exactly to expand number of results sparql query can retrieve?

[megamattc]

Hello,

I have seen in a few places suggestions about how to expand the number of results a sparql query can retrieve from a general wikibase such as in Blazegraph's IOOptimization, as well in documentation for the wdqs container, i.e. increasing the heapsize for Blazegraph.

Similarly, the documentation from MediaWiki gives the following default values for environment variables HEAP_SIZE and MEMORY:

HEAP_SIZE | 16g | Java heap size for Blazegraph
-- | -- | --
MEMORY | -Xms${HEAP_SIZE} -Xmx${HEAP_SIZE} | Full Java memory settings for Blazegraph

I am trying to increase the number of results I can retrieve from my wikibase under a fixed query. Simply increasing the heapsize in docker-compose.yml by setting HEAP_SIZE = 2g (or 4g etc.) does not work.

On the other hand, the IOOptimization documentation says

# Sample JVM options showing allocation of a 4GB managed object heap
 # and allowing a 3GB native heap. Always use the -server mode JVM for
 # Blazegraph.
 -server -Xmx4G -XX:MaxDirectMemorySize=3000m

This looks like a Java command, but I am unsure where to run it. I tried it inside the wdqs container while all containers were up but it did not work.

Does anyone know what I should do with the -server -Xmx4G -XX:MaxDirectMemorySize=3000m command, or how else I could increase the number of results sparql can retrieve at a time?