Bulk scroller should automatically turn to produceImmediate

The default configuration for the scroller is to be atomic, which means that if the scroll fails there is no downstream activity,

The downstream records that contain the document ids are kept in memory and pushed downstream only when scrolling is completed.

It is possible to handles millions of records this way but it will cost few GB of memory.

This can turn into OOM for larger repository, in this case the configuration should be adapted:

 <extension target="org.nuxeo.runtime.ConfigurationService" point="configuration">
     <property name="nuxeo.core.bulk.scroller.produceImmediate">true</property>
     ...

where records are produced downstream while the scroll continues, in the case of failure during scroll the action is partially processed.

We can alleviate the problem using a limit: use an atomic behavior unless we have more than 100k docs.