On Tue, Nov 26, 2013 at 5:34 PM, Alexander Korotkov <aekorot...@gmail.com>wrote:
> On Wed, Nov 20, 2013 at 9:02 PM, Heikki Linnakangas < > hlinnakan...@vmware.com> wrote: > >> On 06.11.2013 17:36, Alvaro Herrera wrote: >> >>> Just for my own illumination, can someone explain this bit? >>> >>> + If a posting list is too large to store in-line in a key entry, a >>> posting tree >>> + is created. A posting tree is a B-tree structure, where the >>> ItemPointer is >>> + used as the key. At the leaf-level, item pointers are stored >>> compressed, in >>> + "varbyte encoding". >>> >>> I think the first ItemPointer mentioned (the key) refers to a TID >>> pointing to the index, and "item pointers stored compressed" refers to >>> the TIDs pointing to the heap (the data). Is that correct? >>> >> >> No, they both refer to TIDs pointing to the heap. >> >> >> I'm also interested in the "FIXME explain varbyte encoding" explanation >>> currently missing, if somebody can write it down ... >>> >> >> Alexander's latest version filled in that explanation (haven't read it >> myself yet) > > > off-list > It appears to be not actually off-list, sorry :) > What's your plans about GIN now? I tried to rebase packed posting lists > with head. But I found that you've changed interface of placeToPage > function. That's conflicts with packed posting lists, because > dataPlaceToPageLeaf needs not only offset number to describe place to > insert item pointer. Do you like to commit rework of handling GIN > incomplete splits before? > ------ With best regards, Alexander Korotkov.
