Re: Maximum extents

Ronald E. Major wrote: > > > > Mark D. Stock wrote: > > > > > > > I didn't see the original question, but the limit of 8 extents per > table > > > > was up to version 5.x, because only the first 8 extents are tracked > in > > > > SHM. > > > > In version 6.x onwards extents are tracked in the virtual portion of > > > > SHM, > > > > and therefore the number is dynamic. > > > > > > cool. i wasn't aware of that. thanks for the update. it's > good when > > > things like this are made dynamic. > > > > > > > This is not so true now in 7.x, but is still a good rule of thumb to > > > > bear > > > > in mind, in order to reduce fragmentation of tables. > > > > > > yes, still, you want to keep the number of extents as low as > possible, > > > performance degradation due to fragmentation. > > > > > > mickm > > > > In 5.x the partition page (slot 5) contains the extent address > > information used to locate the physical data page. Each extent takes up > > 8 bytes. There are other slot entries on this page which expand with > > the table data. The reason for the 200+ number is due to the page size > > of 2k / 8, but varying expansion of other slots data (or something like > > that). It depends on the index, column size...