Sql Cannot establish new connection

• farax_x

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  August 28, 2017 at 1:54 pm

  #345893

  I have Sql Server 2016 running on windows server 2016 (Microsoft SQL Server 2016 (SP1-CU3) (KB4019916) - 13.0.4435.0 (X64)  Enterprise Edition (64-bit) on Windows Server 2016 Datacenter 6.3 <X64> (Build 14393: ) (Hypervisor)
  )
  Server is under large number of concurrent connections and transactions (about 3000 )
  When the number of connections is close to 3000, Sql is no longer able to open a new connection
  But the connections that are already open are working fine!
  Cpu utilization is about 85%
  Max connection is set to 0
   What should I do ?

• Chinnappan Balan

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  August 29, 2017 at 11:38 am

  #1957287

  Each and every connection required some memory allocation, Check for available free memory.

• durai nagarajan

  SSCoach

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  August 29, 2017 at 11:54 pm

  #1957355

  Can you post the exact error screen shot.

  Regards
  Durai Nagarajan

• andreas.kreuzberg

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  August 30, 2017 at 5:41 am

  #1957410

  Hi,
  if you got these kind of error:

  Logon,Unknown,SQL Server failed with error code 0xc0000000 to spawn a thread to process a new login or connection

  Just give the os more memory, and less to the sql server.

  You can select your possibility to create new connections/thread:

  SELECT * FROM sys.dm_os_nodes
  
  Watch for "THREAD_RESOURCES_LOW: No new threads can be created on this node because of a low-memory condition."

  https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-os-nodes-transact-sql

  Kind regards,
  Andreas