On Wed, Nov 05, 2008 at 03:04:42PM +0100, Zdenek Kotala wrote: > Greg Stark napsal(a): > It is exceptional case between V3 and V4 and only on heap, because you save > in varlena. But between V4 and V5 we will lost another 4 bytes in a page > header -> page header will be 28 bytes long but tuple size is same. > > Try to get raw free space on each page in 8.3 database and you probably see > a lot of pages where free space is 0. My last experience is something about > 1-2% of pages.
Is this really such a big deal? You do the null-update on the last tuple of the page and then you do have enough room. So Phase one moves a few tuples to make room. Phase 2 actually converts the pages inplace. Have a nice day, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ > Please line up in a tree and maintain the heap invariant while > boarding. Thank you for flying nlogn airlines.
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