onstat -g seg command: Print shared memory segment statistics
Use the onstat -g seg command to show the statistics for shared memory segments.
This command shows how many segments are attached and their sizes. You can run the onstat -g seg command on a dump file that was created without the buffer pool.
Syntax: >>-onstat-- -g--seg--------------------------------------------><
Example output
Figure 1. onstat -g seg command output
Segment Summary:
id key addr size ovhd class blkused blkfree
720914 52e44801 44000000 4390912 248812 R 1072 0
753683 52e44802 44430000 131072000 769136 V 22573 9427
819221 52e44803 4c130000 66027520 1 B 16120 0
851990 52e44804 50028000 83648512 1 B 20422 0
Total: - - 285138944 - - 60187 9427
Virtual segment low memory reserve (bytes):4194304
Low memory reserve used 0 times and used maximum block size 0 bytes
Output description
- id
- The ID of the shared memory segment
- key
- The shared memory key that is associated with the shared memory segment ID
- addr
- The address of the shared memory segment
- size
- The size of the shared memory segment in bytes
- ovhd
- The size of the shared memory segment control information (overhead) in bytes
- class
- The class of the shared memory segment (B is for Buffferpool, R is for Resident, V is for Virtual, VX is for Virtual Extended, and M is for Message.)
- blkused
- The number of blocks of used memory
- blkfree
- The number of blocks of free memory
- Virtual segment low memory reserve (bytes)
- The size of reserved memory for use when critical activities are needed and the server has limited free memory, specified in bytes (You specify reserved memory in the LOW_MEMORY_RESERVE configuration parameter.)
- Low memory reserve used 0 times and used maximum block size 0 bytes)
- The number times that the server used the reserved memory and the maximum memory needed