Heikki Linnakangas wrote:
We need to give the indexam API some further thought. As you know, I've
been working on the Grouped Index Tuples stuff, which also requires
changes to the API to get full benefit. There's a bunch of functionality
I'd like to see:
* Support for streamed bitmaps, like you have implemented.
* Support for candidate matches. This is needed for GIT, as well as
range-encoded bitmap indexes if/when we add them.
* Support for returning tuples in partial order. This is again needed
for GIT, because grouped tuples don't keep track of the ordering within
the group, so they need to be sorted if ordering necessary. And again
it's also useful to return tuples in order from range-encoded bitmaps.
* Support for kill_prior_tuple on bitmap scans.
* A bulk insert API. When inserting a lot of tuples with similar keys,
we could a considerable amount of CPU with a bulk insert API. A bulk
insert to a B-tree for example would only need to descend the tree once,
find the insert location, lock the target page just once and insert all
the tuples that belong to that page. That would potentially also reduce
WAL traffic.
Forgot one:
* Ability return index tuple contents, not just pointers to heap, to
allow the executor to use the values stored in the index, see
http://archives.postgresql.org/pgsql-performance/2006-09/msg00080.php
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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