Start/notes.ini Parameters/Server_MaxConcurrentTrans

Server_MaxConcurrentTrans

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Parameter: Server_MaxConcurrentTrans
Short description: Maximum number of concurrent transactions the server handles – acts as an upper cap on the NRPC worker threads.

Profile

Parameter
Server_MaxConcurrentTrans
Category
Performance / Memory
Component
Server
Available since
9.0.1
Supported versions
9.0.1, 10.0, 11.0, 12.0, 14.0, 14.5, 14.5.1
GUI equivalent
Server document (Server Tasks → Maximum concurrent transactions)
Possible values
Integer (default 20 × number of CPUs; typically 40–500)

Description

Server_MaxConcurrentTrans limits the number of NRPC transactions processed concurrently. Once the server reaches this value, further requests are queued until a worker thread becomes available.
The default (20 × CPU cores) is sufficient for most environments. On servers with high load (mail hubs, many replicators), a moderate increase can make sense – but values that are too high degrade latency and memory consumption.

Example configuration

Server_MaxConcurrentTrans=200

Notes & pitfalls

  • Do not blindly raise the value – each worker uses memory and may hold locks.
  • Pairs with Server_MaxSessions, Server_Min_Possible_Trans_Time, Server_Max_Possible_Trans_Time.
  • Check current utilization via show stat server.transactions.* and show performance.
  • In cluster environments, scale through load distribution rather than this value alone.
  • The change takes effect after a server restart.