the size of tempfile?

[dervisali]

when i apply "alter database tempfile /path_to_temp01/temp01.dbf resize 500M;" command, i can see via oem that the size takes a value what i set. But in the operating system environment (which is linux) i can not see the changed size with du -ha command. it remains constant. what is the reason of this? will this situation be a problem for the temp file? and How can i calculate the ideal size of this file?

[dbasan]

when i apply "alter database tempfile /path_to_temp01/temp01.dbf resize 500M;" command, i can see via oem that the size takes a value what i set. But in the operating system environment (which is linux) i can not see the changed size with du -ha command. it remains constant. what is the reason of this? will this situation be a problem for the temp file? and How can i calculate the ideal size of this file?

you would see them when the objects occupy the resized space.
Generally you would see them immediately (as in Soalris).

[tomcat]

Sizing of temp depends entirely on your application. DDS / Data whse type stuff, usually requires a larger temp. Straight OLTP - probably smaller temp is fine. Depends on size of data.

See v$sort_usage and v$sort_segment for usage. I monitor mine, so I can tell who is running large sorts.