On 14.07.2011 22:10, Tom Lane wrote:
Heikki Linnakangas<heikki.linnakan...@enterprisedb.com> writes:
Why is the posting tree a tree? AFAICS, we never search it using the
TID, it's always scanned in whole. It would be simpler to store the TIDs
in a posting list in no particular order. This could potentially make
insertions cheaper, as you could just append to the last posting list
page for the key, instead of traversing the posting tree to a particular
location. You could also pack the tids denser, as you wouldn't need to
reserve free space for additions in the middle.
Surely VACUUM would like to search it by TID for deletion purposes?
It doesn't, it scans all the tid lists in whole. I guess it could search
by TID, it could be a win if there's only a few deleted tuples, in a
small range of pages.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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