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  1. Solution Center
  2. SOL-39

Connection management in EXASolution (query queue)

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    • Type: Explanation
    • Status: Obsolete
    • Affects Version/s: EXASolution 4.1.0, EXASolution 4.2.0
    • Fix Version/s: None
    • Component/s: None
    • Labels:
      None
    • Explanation:
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      Before EXASolution 4.2
      In case of a memory shortage EXASolutions resource management will ask all sql processes to stop. They will terminate if all of the following conditions are matched (safe disconnect):

      • no open transaction
      • no open prepared statement
      • no open resultset
      • no open subconnection

      If the user executes a command, the driver will perform a reconnect. The user won't notice the connection loss or the reconnect. The entry for this session in EXA_*_SESSIONS has the status IDLE after the safe disconnect.

      EXASolution 4.2
      EXASolution will ask all connected sql processes to be recycled if at least 80% of the maximum concurrent connections are in use (default: 100). The conditions for the process recycling are identical (see above). EXASolution uses the free sql process for other connections.

      Please note that connections with AUTOCOMMIT OFF cannot be recycled unless a commit is explicitly executed. This is especially important in the case of long-running sessions waiting for data. To avoid the queue overflow please execute a commit after the login.

      Sessions without a sql process are still displayed in EXA_*_SESSIONS.

      EXASolution 5.0
      Connections with AUTOCOMMIT OFF can be recycled without a explicit commit.

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      Before EXASolution 4.2 In case of a memory shortage EXASolutions resource management will ask all sql processes to stop. They will terminate if all of the following conditions are matched (safe disconnect): no open transaction no open prepared statement no open resultset no open subconnection If the user executes a command, the driver will perform a reconnect. The user won't notice the connection loss or the reconnect. The entry for this session in EXA_*_SESSIONS has the status IDLE after the safe disconnect. EXASolution 4.2 EXASolution will ask all connected sql processes to be recycled if at least 80% of the maximum concurrent connections are in use (default: 100). The conditions for the process recycling are identical (see above). EXASolution uses the free sql process for other connections. Please note that connections with AUTOCOMMIT OFF cannot be recycled unless a commit is explicitly executed. This is especially important in the case of long-running sessions waiting for data. To avoid the queue overflow please execute a commit after the login. Sessions without a sql process are still displayed in EXA_*_SESSIONS. EXASolution 5.0 Connections with AUTOCOMMIT OFF can be recycled without a explicit commit.
    • Category 1:
      Database Administration

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            • Assignee:
              CaptainEXA Captain EXASOL
              Reporter:
              CaptainEXA Captain EXASOL
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              • Created:
                Updated:
                Resolved: