RE: number of extents

There is a limit to the number of page extents you can have per table which varies according to your page size and how you are using the table. For a simple table (no odd data types, no gls, limited indices) on a 2K page I figure it at about 150 extents. For a 4K page you should get much higher. You can check the fullness of the partition page which points to your table by: oncheck -pt database:tabname Take the Physical address (first line) e.g.: Physical Address 100033 Break it apart into Chunk and page offset: (1, 00033) oncheck -pP 0x1 0x33 This will show you the partition page for the table in question. My understanding is that if the page fills you're SOL. "frcnt" is the number of bytes left on the page, and it takes 12 bytes to describe each extent. (Logical page, Physical Address, Slot entry). Try to use this power only for good. Realize also, that it makes little sense to rebuild just one table in a dbspace/chunk/slice. Perhaps you have the contiguous space aropund to fit it all into one extent, but you're leaving all of those newly freed bits in little drabs around the dbspace. If you really want to clean up, unload everything on the space/chunk/slice and rebuild it. While it doesn't make as much of a difference under 7+.x as it did under 5.x. I start keeping an eye on tables which get over 4 extents. If the dbspace looks like spaghetti, I rebuild it. For example - I'll let this one slide: (Names changed to protect the innocent - this is one chunk/space within a 16-wide slice) Chunk: xxxx Size: 8192.00 Used: 5739.57 Ckfree: 2452.43 PctFree: 29.94 Tab1 0.02 Extents 1 Tab2 0.02 Extents 1 Tab3 0.75 Extents 1 Tab4 5665.94 Extents 5 ***** Tab5 0.03 Extents 2 Tab6 20.00 Extents 1 Tab7 29.88 Extents 8 ***** Tab8 20.00 Extents 1 While this one could stand a rebuild: (this is one chunk/space within a 32-wide slice) Chunk: xxxx Size: 8192.00 Used: 5568.00 Ckfree: 2624.00 PctFree: 32.03 Tab10 181.25 Extents 1 Tab11 2395.45 Extents 9 ***** Tab12 2871.09 Extents 15 ***** Tab13 10.00 Extents 1 Tab14 110.00 Extents 4 ***** (furthermore, in my environment, I'm wondering what those itty-bitty tables are doing on my main drives. (tabs1,2,3,5,6,7,8 and 13) - sigh getting close to spring cleaning time). cheers j. > -----Original Message----- > From: Andrew Hamm [mailto:ahamm@sanderson.net.au] > Sent: Wednesday, January 31, 2001 1:03 AM > To: informix-list@iiug.org > Subject: Re: number of extents > > > David Williams (and others) wrote ... > > > We tend to hit a limit around 180-200 extents. >20 needs > looking at, > > [Deletia]