Re: tbtape question

> > > Surely, 're-extenting' tables will effectively shrink them. As I > understand it tbunload/ tbload work at page level, so the only defragging > that won't get done is that within pages (of which the only examples I > can think of are pages with deleted rows, reallocation of modified > varchars and index compression), and physical page sequence. > Not in my personal experience using Online 4.11.... I have tbunloaded and tbloaded databases with large amounts of deleted rows, and had them expand with the tbload. I would imagine two things (at least) that can cause this. One, even if one row is left in an extent, due to some odd twist of hashing fate, the entire extent will remain intact. And two, (this is slightly bizarre), if the original table was created with freakily large first extents, I believe it will use that extent, no matter how many rows it has. One of our customers inadvertantly created a first extent with 2,000,000 pages, instead of 200,000. The tbload failed because it used such a big extent for the table, that nothing was left for the other tables. > Completely dead pages will not get re-created, and tbload will only > allocate sufficient extents to accommodate the pages which have got > something in them. I have not seen this in practice to be true. tbloads are often bigger than the original buggers. Really. Been there. Done that. In fact, it bit us big time in the butt. > The simplest way to force complete table compression is ALTER INDEX TO > CLUSTER (IIRC this is what the manual recommends), but you have to have > enough room in the dbspace for the new, re-built table before it drops > the old one. Yup, but we love this method as well, as its a pretty cheap and fast trick. If I remember correctly, even on tables with zillions on rows, we didnt have to turn off logging and exlusively lock the table. Can anyone confirm this on hugo-grande tables? We did have to alter our dbdiff to not consider the index changed if the only difference was clustering. -- Naomi Walker (aka N7FSA) | naomi@anasazi.com | Phoenix, Arizona ----------------------------------------------------------------- Dyslexsics, Untie! | Visualize Whirled Peas