On 8-6-2012 18:07, Ann Harrison wrote: > On Fri, Jun 8, 2012 at 11:24 AM, Alec Swan <alecs...@gmail.com> wrote: > >> Thanks Vlad, but this is too complicated to give as a guidance to our >> customers. However, it sounds like rebuilding an index cannot require more >> space that the database size itself, right? > > > On a bad day, yes it could. To have a day that bad, you'd have to have > keys that are most of the size of the record, with columns that are often > null, zero, or contain values much smaller than the declared size of the > column. There may be a situation during the merge phase of the sort when > there's more than one copy of each record.
Question out of curiosity: why does an index rebuild actually require a sort? I would think that for an index rebuild this would be sufficient: * deactivate index * clear index * for each record (sequential read of all pages?) * insert column value into index * activate index These steps would not require any additional temporary space. -- Mark Rotteveel
