Simon Riggs wrote:
It would also be possible to introduce a special tweak there which is that if the block is not in cache, don't read it in at all. If its not in cache we know that nobody has a pin on it, so don't need to read it in just to say "got the lock". That icing for later.
Heh, that's clever :-). We could actually use a method like that to solve the whole problem. After the (replay of the) b-tree vacuum is finished, scan through all shared buffers, and get a vacuum lock on every page of that index that's in cache. Groveling through all shared buffers would be slower for small indexes, though.
I believe the "vacuum lock every leaf page" behavior is only needed for system catalogs. You have other issues with those still, namely that table locks are not yet taken appropriately, so I'm not sure if this is worth worrying about until that's done.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
