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  1. MariaDB MaxScale
  2. MXS-7705

Client waits for a connection for up to 1 s while the MaxScale thread uses 100 % CPU

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 25.10.0, 26.10.0
    • 25.10.5, 26.10.1
    • Core
    • None
    • Can result in unexpected behaviour
    • Under certain conditions with idle_session_pool_time set, MaxScale used 100% of the CPU for a brief moment.

    Description

      A client that waits for a free server connection is served late. The wait starts when another session closes and releases the connection. During the wait, one MaxScale thread uses 100 % CPU.
      Conditions (all required):

      • idle_session_pool_time is set on the service
      • The server has reached max_routing_connections and a client is waiting
      • The connection is freed by a closing session
      • MaxScale has no other traffic on that thread
        Impact: Low. Under load the delay is a few milliseconds.
        Affected versions: 25.10.0 and later
        Reproduce: threads=1, max_routing_connections=1, idle_session_pool_time=30s. Client A holds a transaction open. Client B sends a query and waits. Disconnect A abruptly.
        Workaround: None needed.

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            markus makela markus makela
            johan.wikman Johan Wikman
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            Dates

              Created:
              Updated:
              Resolved:

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