Calculate proximity in the DB for speed

We need to calculate and store a (potenially adjusted) proxmity for
each hold and copy for use in targetting and optimization of op
capture.  Before this commit, we do that within the hold target
code itself.  Now we'll do it when the hold-copy map is inserted,
because we have the same information available at that time as we
have in the targeter.  This will both speed up the apparent cost of
the calculation, because it avoids the cost of a network round-trip,
and the total number of SELECTs we must issue, because the proximity
value will now be cached for use by the proximity map function.

Backward compatability is retained for the create_prox_map() function
in case any other code is depending on that.

Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>
Conflicts:
	Open-ILS/src/perlmods/lib/OpenILS/Application/Storage/Publisher/action.pm

diff --git a/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.pre-calculate-prox-adjustment.sql b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.pre-calculate-prox-adjustment.sql
new file mode 100644 (file)
index 0000000..723699d
--- /dev/null
+++ b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.pre-calculate-prox-adjustment.sql
@@ -0,0 +1,16 @@
+BEGIN;
+
+CREATE OR REPLACE FUNCTION action.hold_copy_calculated_proximity_update () RETURNS TRIGGER AS $f$
+BEGIN
+    NEW.proximity := action.hold_copy_calculated_proximity(NEW.hold,NEW.target_copy);
+    RETURN NEW;
+END;
+$f$ LANGUAGE PLPGSQL;
+
+CREATE TRIGGER hold_copy_proximity_update_tgr BEFORE INSERT OR UPDATE ON action.hold_copy_map FOR EACH ROW EXECUTE PROCEDURE action.hold_copy_calculated_proximity_update ();
+
+-- Now, cause the update we need in a HOT-friendly manner (http://pgsql.tapoueh.org/site/html/misc/hot.html)
+UPDATE action.hold_copy_map SET proximity = proximity WHERE proximity IS NULL;
+
+COMMIT;
+