Heikki.
I have idea. when i begining vacuum i must create structure like hash table. And the first action i fill this hash table.
in code this look like:
for( blkno = ..; all pages; blkno++) {
if(! gistPageIsLeaf(blkno)) {
for( all tuples in blkno ) {
hash[ blkno that is referenced by the tuple] = blkno;
}
}
}
getting is parent of page is fast and simple( hash[page] ).
But this solution is need 2 full reading of index.
but Alexander says me that: this solution may be have a problem, because there is maintenance_work_mem.
