# Copyright (C) 2022-present MongoDB, Inc.
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global:
  cpp_namespace: "mongo"
  cpp_includes:
    - "mongo/db/admission/ticketholder_manager.h"
    - "mongo/db/admission/concurrency_adjustment_validator.h"

enums:
  StorageEngineConcurrencyAdjustmentAlgorithm:
    description: "Algorithm for adjusting the number of concurrent storage engine transactions"
    type: string
    # 'kFixedConcurrentTransactions': Number of concurrent transactions are controlled by
    # storageEngineConcurrentWriteTransactions/storageEngineConcurrentReadTransactions and will
    # not be adjusted automatically based on overall system throughput.
    #
    # 'kThroughputProbing': Number of concurrent transactions are dynamically adjusted, either
    # increasing or decreasing concurrency in the storage engine, based on system throughput.
    values:
      kFixedConcurrentTransactions: "fixedConcurrentTransactions"
      kThroughputProbing: "throughputProbing"

server_parameters:
  storageEngineConcurrentWriteTransactions:
    description: "Storage Engine Concurrent Write Transactions"
    set_at: [ startup, runtime ]
    cpp_vartype: AtomicWord<int32_t>
    cpp_varname: gConcurrentWriteTransactions
    on_update: "admission::TicketHolderManager::updateConcurrentWriteTransactions"
    deprecated_name:
      - wiredTigerConcurrentWriteTransactions
    # Default value being 0 on startup means we're allowing the underlying storage engines 
    # to use their default values. Updating it to 0 again after startup does not use the default value.
    # This parameter is only compatible with the 'kFixedConcurrentTransactions' option for
    # storageEngineConcurrencyAdjustmentAlgorithm.
    default: 0
    validator:
      callback: "admission::TicketHolderManager::validateConcurrentWriteTransactions"
    redact: false

  storageEngineConcurrentReadTransactions:
    description: "Storage Engine Concurrent Read Transactions"
    set_at: [ startup, runtime ]
    cpp_vartype: AtomicWord<int32_t>
    cpp_varname: gConcurrentReadTransactions
    on_update: "admission::TicketHolderManager::updateConcurrentReadTransactions"
    deprecated_name:
      - wiredTigerConcurrentReadTransactions
    # Default value being 0 on startup means we're allowing the underlying storage engines 
    # to use their default values. Updating it to 0 again after startup does not use the default value.
    # This parameter is only compatible with the 'kFixedConcurrentTransactions' option for
    # storageEngineConcurrencyAdjustmentAlgorithm.
    default: 0
    validator:
      callback: "admission::TicketHolderManager::validateConcurrentReadTransactions"
    redact: false

  lowPriorityAdmissionBypassThreshold:
    description: >-
        Only applicable when Deprioritization is enabled for global lock ticket admission. Limits
        the number of consecutive times a queue of low-priority operations is bypassed in favor of
        waking normal-priority operations for ticket admission. Once the threshold is met, an
        operation from the low-priority queue will be woken for ticket admission.
    set_at: [ startup, runtime ]
    cpp_vartype: AtomicWord<int32_t>
    cpp_varname: gLowPriorityAdmissionBypassThreshold
    on_update: "admission::TicketHolderManager::updateLowPriorityAdmissionBypassThreshold"
    # 0 means low priority operations will never be admitted when there are normal priority
    # operations waiting for ticket admission.
    default: 5000
    validator:
      gte: 0
    redact: false

  storageEngineConcurrencyAdjustmentAlgorithm:
    description: >-
      The algorithm to be used for adjusting the number of concurrent storage engine transactions.
    set_at: startup
    cpp_vartype: std::string
    cpp_varname: gStorageEngineConcurrencyAdjustmentAlgorithm
    default: "throughputProbing"
    validator:
      callback: validateConcurrencyAdjustmentAlgorithm
    redact: false

  storageEngineConcurrencyAdjustmentIntervalMillis:
    description: >-
      The interval in milliseconds in which to run the concurrency adjustment algorithm, if it is
      not set to fixedConcurrentTransactions.
    set_at: startup
    cpp_vartype: int32_t
    cpp_varname: gStorageEngineConcurrencyAdjustmentIntervalMillis
    default: 100
    validator:
      gte: 10
    redact: false