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sys.dm_fts_memory_buffers

Updated: 12 December 2006

Returns information about memory buffers belonging to a specific memory pool that are used as part of a full-text crawl or a full-text crawl range. This dynamic management view can be used to determine the shared memory usage of a full-text population.

Column name Data type Description

pool_id

int

ID of the allocated memory pool.

0 = Small buffers

1 = Large buffers

memory_address

varbinary(8)

Address of the allocated memory buffer.

name

nvarchar(8000)

Name of the shared memory buffer for which this allocation was made.

is_free

bit

Current state of memory buffer.

0 = Busy

1 = Free

row_count

int

Number of rows that this buffer is currently handling.

bytes_used

int

Amount, in bytes, of memory in use in this buffer.

percent_used

int

Percentage of allocated memory used.

Requires VIEW SERVER STATE permission on the server.

From To Relationship

dm_fts_memory_buffers.pool_id

dm_fts_memory_pools.pool_id

Many-to-one

A. Returning shared memory usage for all active populations.

The following example returns the shared memory usage for all active full-text populations.

SELECT SUM(pools.buffer_size) FROM sys.dm_fts_memory_pools pools
    JOIN sys.dm_fts_memory_buffers buffers 
    ON (pools.pool_id = buffers.pool_id)
    WHERE buffers.is_free = 0

B. Determining the efficiency of full-text shared memory usage

The following example returns the average percentage of memory that is being used for all active full-text memory buffers.

SELECT AVG(percent_used) AS "memory usage efficiency" 
    FROM sys.dm_fts_memory_buffers 
    WHERE is_free = 0

Release History

12 December 2006

New content:
  • Added the examples.
Changed content:
  • Fixed the description of the is_free field.
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