---
fixes:
  - Evaluation of final workflow context was very heavy in cases
    when the workflow had a lot of parallel tasks with large
    inbound contexts. Merging of those contexts in order to
    evaluate the workflow output consumed a lot of memory.
    Now this algorithm is rewritten with batched DB query and
    Python generators so that GS has a chance to destroy
    objects that have already been processed. Previously all
    task executions had to stay in memory until the end of the
    processing. The result is that now it consumes 3 times less
    memory on heavy cases.