Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-57483

Results from $lookup stage are not cached for a resharding operation's sub-pipeline

    • Fully Compatible
    • ALL
    • v5.0
    • Sharding 2021-06-14
    • 1

      DocumentSourceLookUp::buildPipeline() calls ShardServerProcessInterface::attachCursorSourceToPipeline() which calls sharded_agg_helpers::attachCursorToPipeline() and always serializes and re-parses, even when the pipeline may execute locally on the shard via ShardServerProcessInterface::attachCursorSourceToPipelineForLocalRead().

      Because the $sequentialCache stage omits itself from the serialized pipeline, the parsed pipeline which executes locally on the shard won't ever use the cache.

            Assignee:
            max.hirschhorn@mongodb.com Max Hirschhorn
            Reporter:
            max.hirschhorn@mongodb.com Max Hirschhorn
            Votes:
            0 Vote for this issue
            Watchers:
            9 Start watching this issue

              Created:
              Updated:
              Resolved: