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title: "ALTER EXTERNAL RESOURCE POOL (Transact-SQL) | Microsoft Docs"
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# ALTER EXTERNAL RESOURCE POOL (Transact-SQL)
[!INCLUDE[tsql-appliesto-ss2016-xxxx-xxxx-xxx_md](../../includes/tsql-appliesto-ss2016-xxxx-xxxx-xxx-md.md)]

  Changes Resource Governor external pool that was defined resources for external processes. For R Services the external pool governs `rterm.exe`, `BxlServer.exe`, and other processes spawned by them.  
  
 ![Topic link icon](../../database-engine/configure-windows/media/topic-link.gif "Topic link icon") [Transact-SQL Syntax Conventions](../../t-sql/language-elements/transact-sql-syntax-conventions-transact-sql.md).  
  
## Syntax  
  
```  
ALTER EXTERNAL RESOURCE POOL { pool_name | "default" }  
[ WITH (  
    [ MAX_CPU_PERCENT = value ]  
    [ [ , ] AFFINITY CPU =    
            {  
                AUTO   
              | ( <cpu_range_spec> )   
              | NUMANODE = (( <NUMA_node_id> )   
            } ]   
    [ [ , ] MAX_MEMORY_PERCENT = value ]  
    [ [ , ] MAX_PROCESSES = value ]   
    )   
]  
[ ; ]  
  
<CPU_range_spec> ::=    
{ CPU_ID | CPU_ID  TO CPU_ID } [ ,...n ]  
```  
  
## Arguments  
 { *pool_name* | "default" }  
 Is the name of an existing user-defined external resource pool or the default external resource pool that is created when [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] is installed.  
"default" must be enclosed by quotation marks ("") or brackets ([]) when used with `ALTER EXTERNAL RESOURCE POOL` to avoid conflict with `DEFAULT`, which is a system reserved word.  
  
 MAX_CPU_PERCENT =*value*  
 Specifies the maximum average CPU bandwidth that all requests in the external resource pool will receive when there is CPU contention. *value* is an integer with a default setting of 100. The allowed range for *value* is from 1 through 100.  
  
AFFINITY {CPU = AUTO | ( \<CPU_range_spec> ) | NUMANODE = (\<NUMA_node_range_spec>)}
 Attach the external resource pool to specific CPUs. The default value is AUTO.  
  
AFFINITY CPU = **(** \<CPU_range_spec> **)** maps the external resource pool to the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] CPUs identified by the given CPU_IDs.
  
When you use AFFINITY NUMANODE = **(** \<NUMA_node_range_spec> **)**, the external resource pool is affinitized to the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] physical CPUs that correspond to the given NUMA node or range of nodes.
  
 MAX_MEMORY_PERCENT =*value*  
 Specifies the total server memory that can be used by requests in this external resource pool. *value* is an integer with a default setting of 100. The allowed range for *value* is from 1 through 100.  
  
 MAX_PROCESSES =*value*  
 Specifies the maximum number of processes allowed for the external resource pool. Specify 0 to set an unlimited threshold for the pool which will be bound only be computer resources. The default is 0.  
  
## Remarks  
 The [!INCLUDE[ssDE](../../includes/ssde-md.md)] implements resource pool when you execute the [ALTER RESOURCE GOVERNOR RECONFIGURE](../../t-sql/statements/alter-resource-governor-transact-sql.md) statement.  
  
 For more information on resource pools, see [Resource Governor Resource Pool](../../relational-databases/resource-governor/resource-governor-resource-pool.md), [sys.resource_governor_external_resource_pools &#40;Transact-SQL&#41;](../../relational-databases/system-catalog-views/sys-resource-governor-external-resource-pools-transact-sql.md), and [sys.dm_resource_governor_external_resource_pool_affinity &#40;Transact-SQL&#41;](../../relational-databases/system-dynamic-management-views/sys-dm-resource-governor-external-resource-pool-affinity-transact-sql.md).  
  
## Permissions  
 Requires `CONTROL SERVER` permission.  
  
## Examples  
 The following statement changes an external pool restricting the  CPU usage to 50 percent and the maximum memory to 25 percent of the available memory on the computer.  
  
```  
ALTER EXTERNAL RESOURCE POOL ep_1  
WITH (  
    MAX_CPU_PERCENT = 50  
    , AFFINITY CPU = AUTO  
    , MAX_MEMORY_PERCENT = 25  
);  
GO  
ALTER RESOURCE GOVERNOR RECONFIGURE;  
GO  
```  
  
## See Also  
 [external scripts enabled Server Configuration Option](../../database-engine/configure-windows/external-scripts-enabled-server-configuration-option.md)   
 [SQL Server R Services](../../advanced-analytics/r-services/sql-server-r-services.md)   
 [Known Issues for SQL Server R Services](../../advanced-analytics/r-services/known-issues-for-sql-server-r-services.md)   
 [CREATE EXTERNAL RESOURCE POOL &#40;Transact-SQL&#41;](../../t-sql/statements/create-external-resource-pool-transact-sql.md)   
 [DROP EXTERNAL RESOURCE POOL &#40;Transact-SQL&#41;](../../t-sql/statements/drop-external-resource-pool-transact-sql.md)   
 [ALTER RESOURCE POOL &#40;Transact-SQL&#41;](../../t-sql/statements/alter-resource-pool-transact-sql.md)   
 [CREATE WORKLOAD GROUP &#40;Transact-SQL&#41;](../../t-sql/statements/create-workload-group-transact-sql.md)   
 [Resource Governor Resource Pool](../../relational-databases/resource-governor/resource-governor-resource-pool.md)   
 [ALTER RESOURCE GOVERNOR &#40;Transact-SQL&#41;](../../t-sql/statements/alter-resource-governor-transact-sql.md)