Heikki Linnakangas escribió: > On 04.11.2013 23:44, Alexander Korotkov wrote: > >Attached version of patch has support of old page format. Patch still needs > >more documentation and probably refactoring, but I believe idea is clear > >and it can be reviewed. In the patch I have to revert change of null > >category placement for compatibility with old posting list format. > > I committed some of the refactorings and cleanup included in this > patch. Attached is a rebased version that applies over current head. > I hope I didn't joggle your elbow..
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? I'm also interested in the "FIXME explain varbyte encoding" explanation currently missing, if somebody can write it down ... Thanks, -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
