caching extention for org tree traversal

git-svn-id: svn://svn.open-ils.org/ILS/trunk@16780 dcc99617-32d9-48b4-a31d-7c20da2025e4

diff --git a/Open-ILS/src/sql/Pg/pgmemcache-ou_tree_traversal_cache.sql b/Open-ILS/src/sql/Pg/pgmemcache-ou_tree_traversal_cache.sql
new file mode 100644 (file)
index 0000000..111e356
--- /dev/null
+++ b/Open-ILS/src/sql/Pg/pgmemcache-ou_tree_traversal_cache.sql
@@ -0,0 +1,98 @@
+BEGIN;
+
+/*
+ * Use pgmemcache and memcached to increase the speed of org tree traversal
+ * ------------------------------------------------------------------------
+ *
+ * This set of functions allows the use of memcached as a caching mechanism for
+ * org tree traversal checks.  It is transparent and optional.  If memcache is
+ * not set up, either by not running or the lack of the pgmemcache postgres
+ * addon, then the default, existing behaviour is preserved and live database
+ * queries are used to test all org tree traversals.
+ *
+ * This Evergreen addon extention requires the pgmemcache-perm_cache.sql to be
+ * installed as well.  See that extention script for details on pgmemcache
+ * setup and installation.
+ *
+ * TODO: Make the cache timeout configurable via a global setting for EG 2.0
+ *
+ */
+
+
+CREATE OR REPLACE FUNCTION actor.org_unit_descendants ( INT, INT ) RETURNS SETOF actor.org_unit AS $$
+    SELECT  * FROM  actor.org_unit_descendants( (actor.org_unit_ancestor_at_depth($1,$2)).id );
+$$ LANGUAGE SQL STABLE;
+
+CREATE OR REPLACE FUNCTION actor.noncached_org_unit_descendants ( org INT ) RETURNS SETOF actor.org_unit AS $$
+DECLARE
+    kid             actor.org_unit%ROWTYPE;
+    curr_org        actor.org_unit%ROWTYPE;
+BEGIN
+
+    SELECT * INTO curr_org FROM actor.org_unit WHERE id = org;
+    RETURN NEXT curr_org;
+
+    FOR kid IN SELECT * FROM actor.org_unit WHERE parent_ou = org LOOP
+        FOR curr_org IN SELECT * FROM actor.noncached_org_unit_descendants(kid.id) LOOP
+            RETURN NEXT curr_org;
+        END LOOP;
+    END LOOP;
+
+    RETURN;
+END;
+$$ LANGUAGE PLPGSQL;
+
+CREATE OR REPLACE FUNCTION actor.org_unit_descendants ( org INT ) RETURNS SETOF actor.org_unit AS $func$
+DECLARE
+    kid             actor.org_unit%ROWTYPE;
+    curr_org        actor.org_unit%ROWTYPE;
+    idlist          INT[] := '{}'::INT[];
+    cached_value    RECORD;
+BEGIN
+
+    IF permission.mc_init() THEN
+        -- RAISE NOTICE 'Getting perm from cache';
+        EXECUTE $$SELECT memcache_get('oils_orgcache_$$ || org || $$') AS x;$$ INTO cached_value;
+
+        IF cached_value.x IS NOT NULL THEN
+            FOR curr_org IN
+                SELECT  *
+                  FROM  actor.org_unit
+                  WHERE id IN ( SELECT * FROM explode_array( STRING_TO_ARRAY( cached_value.x, ',' ) ) )
+            LOOP
+                RETURN NEXT curr_org;
+            END LOOP;
+    
+            RETURN;
+        END IF;
+
+    END IF;
+
+    SELECT * INTO curr_org FROM actor.org_unit WHERE id = org;
+    RETURN NEXT curr_org;
+
+    idlist := ARRAY_APPEND( idlist, curr_org.id );
+
+    FOR kid IN SELECT * FROM actor.org_unit WHERE parent_ou = org LOOP
+        FOR curr_org IN SELECT * FROM actor.noncached_org_unit_descendants(kid.id) LOOP
+            RETURN NEXT curr_org;
+            idlist := ARRAY_APPEND( idlist, curr_org.id );
+        END LOOP;
+    END LOOP;
+
+    IF permission.mc_init() THEN
+        EXECUTE $$
+            SELECT memcache_set(
+                'oils_orgcache_$$ || org || $$',
+                $$ || QUOTE_LITERAL(ARRAY_TO_STRING(idlist,',')) || $$,
+                '10 minutes'::INTERVAL
+            );
+        $$;
+    END IF;
+
+    RETURN;
+END;
+$func$ LANGUAGE PLPGSQL;
+
+COMMIT;
+