informix server config 200M shmvirtsize and 100M shmadd，But we find everyday,It will increase a share memory segment(100M),any way can I find out why the shmvirtsize turn to large? what operation will cause this situation? Thanks

Hi,

I suggest that you increase SHMVIRTSIZE=300M, but SHMADD=32768.
If the on-line allocate virtual segment, then increase SHMVIRTSIZE.
Some of the causes is update statistics, oncheck of indices, orde by bigs.


Gustavo.

Virtual Seg holds memory for connections, SQL statement memory for prepares/stored procedures, active result sets - basically anything that is not a data row (which goes to the buffer segment). Memory leaks like new SQL cursors being created but never closed or a large number of users running programs with lots of sql and returned rows can typically flood the virtual segment. You can remove 'stale' chunks of used memory using the 'onmode -F' command which can reduce the used % of the segment but it causes a brief performance hit while the search for stale memory is completed.