Re: dbspace stat

oncheck -pT takes some time for larger tables which suggests to me thatit scans the table rather than simply querying the sysmaster tables. It would seem that the current number of pages used in a table can't be obtained through the sysmaster tables. However, I have noticed on occasion a *decrease* in ti_npused for a given table. Could it be that ti_npused is in fact set to a currently correct value under certain conditions? Here are some candidate conditions: - Update statistics (nope, tested that). - Reboot of the database engine (nope, tested that). - Version upgrade of the database engine. Maybe someone from Informix could say. June Tong wrote: > > mosserp@WellsFargo.COM wrote: > > > Recently, we have been trying to find out how to get not only total_space > > (sum (chksize)) and allocated_space (sum (chksize - nfree)), but also the > > amount of space actually USED within the extents. The closest we've come is > > sysmaster:systabinfo.ti_npused (comes from sysptnhdr.npused), which is at > > the tablespace/partition level. This is the same datum that shows up in > > oncheck -pT output.> > > > The problem with this is that ti_npused, according to Informix, is the > > MAXIMUM number of pages that have been used SO FAR, i.e., it's basically a > > "high-water" mark. That means that large deletes, freeing up large numbers > > of pages, would NOT reduce npused! But something that I saw in a posting > > from June recently SEEMED to imply that npused is intended to go up AND DOWN > > as pages are used/freed. June, can you comment? Or anyone else for that > > matter? > > *I* said that??? I think I was talking about npdata, which does go up and > down. It is definitely true that npused never goes down. > > I always use oncheck -pT to show the number of data, index, bit-map, BLOB and > free pages. AFAIK, this is always accurate. This information must be in > sysmaster somewhere, but I don't know where. > > June > -- > june_t@hotmail.com > Grounded in Palo Alto, living on M&M's (plain) ________________________________________________________________ John H. Frantz Power-4gl: Extending Informix-4gl john@rl.is http://www.rl.is/~john/pow4gl.html