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  1. Core Server
  2. SERVER-81132

Avoid scanning entire routing table during $merge stage planning

    • Type: Icon: Bug Bug
    • Resolution: Unresolved
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 4.2.24, 4.4.24, 6.0.10, 5.0.21, 7.1.0-rc2
    • Component/s: None
    • None
    • Query Optimization
    • ALL

      In SERVER-35905 we added a logic to partition a $merge stage on the shards.
      This logic requires scanning the entire routing table for the collection that before 7.0+ could potentially contain millions of entry.
      For collections of large number of chunks, this logic could take seconds to be executed.
      Additionally, this logic is creating a vector of the size of the routing table, potentially consuming several GBs of RAM.

            Assignee:
            backlog-query-optimization [DO NOT USE] Backlog - Query Optimization
            Reporter:
            tommaso.tocci@mongodb.com Tommaso Tocci
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              Created:
              Updated: