Re: extent problem

If you do not specify your extent size at object creation then Informix will default your extent size to 8 pages. The Informix extent algorithm doubles every 16 extents so extents 17-32 will be made up of 16 pages, 33-48 will be 32 pages per extent and so on and so on. You can man- ually assign initial extent size (highly recommended), it does not have to be 8 page (min extent size is 4 pages) allocations. When allocating extents Informix starts with the first chunk and works it's way to the last chunk (numeric sequence, chunk ordering by cron- ological sequence) trying to find contiguous space equal to the size of the extent. Informix will not create an extent that spans chunks, instead if it cannot find a large enough contiguous extent, it will allocate the largest extent possible given the available space after considering all chunks. In addition Informix will not give you an error message telling you if your extent allocation failed and instead you were allocated only a small fraction of that extent space. You can see that the doubling effect can get out of control quickly and if your dbspace is comprised of multiple chunks these can be excessively fragmented within a very short time. It would be interest- ing to determine where the 'free space' is that your dbspace has left and how fragmented it is ? 1) Check your disk space to ensure you actually have the space you think you have, that underlays the Informix chunks. One of the resolutions for the -271 error is that Informix thinks you have a no more available space on the device in question. 2) Assuming cooked devs, check the ulimit on the Informix user is sufficient to allow filesystem consumption as per your table load. 3) Assuming you are dealing with a very large table that will likely use most or all of the dbspace in question, try setting your initial extent to the size of the primary chunk, if all subsequent chunks are the same size you can assign up 8 chunks to the dbspace before you have to consider the effect of extent-doubling. Moreover, your system will not be thrashing itself trying to continuously allocate extents for a table load. This is unneccess- ary overhead that can be easily avoided. The Informix sysadmin manuals are very clear on extent architect- ure. When you get a chance I recommend broadening your under- standing of how this fits into the scheme of things. have a nice day. Yan Zhu wrote: > hey all: > > Trying to load a table, having the following problem: > > 271: Could not insert new row into the table. 136: ISAM error: no> more extents > 847: Error in load file line 59770.> > hmm, what does this mean? and how can I fix it? I don't even remeber > setting up extents when I create the tables. > I checked the dbspace, plenty left, how could it run out? > > running 7.23 on solaris 7.0. > > thanks a lot guys. > > yan