Copy cartodb lib/sql scripts from CDB_CartodbfyTable branch

scripts-available/CDB_QueryTables.sql

@@ -0,0 +1,62 @@
+-- Return an array of table names scanned by a given query
+--
+-- Requires PostgreSQL 9.x+
+--
+CREATE OR REPLACE FUNCTION CDB_QueryTables(query text)
+RETURNS name[]
+AS $$
+DECLARE
+  exp XML;
+  tables NAME[];
+  rec RECORD;
+  rec2 RECORD;
+BEGIN
+  
+  tables := '{}';
+
+  FOR rec IN SELECT CDB_QueryStatements(query) q LOOP
+
+    IF NOT ( rec.q ilike 'select %' or rec.q ilike 'with %' ) THEN
+      --RAISE WARNING 'Skipping %', rec.q;
+      CONTINUE;
+    END IF;
+
+    BEGIN
+      EXECUTE 'EXPLAIN (FORMAT XML) ' || rec.q INTO STRICT exp;
+    EXCEPTION WHEN others THEN
+      -- TODO: if error is 'relation "xxxxxx" does not exist', take xxxxxx as
+      --       the affected table ?
+      RAISE WARNING 'CDB_QueryTables cannot explain query: % (%: %)', rec.q, SQLSTATE, SQLERRM;
+      RAISE EXCEPTION '%', SQLERRM;
+      CONTINUE;
+    END;
+
+    -- Now need to extract all values of <Relation-Name>
+
+    --RAISE DEBUG 'Explain: %', exp;
+
+    FOR rec2 IN WITH
+      inp AS ( SELECT xpath('//x:Relation-Name/text()', exp, ARRAY[ARRAY['x', 'http://www.postgresql.org/2009/explain']]) as x )
+      SELECT unnest(x)::name as p from inp
+    LOOP
+      --RAISE DEBUG 'tab: %', rec2.p;
+      tables := array_append(tables, rec2.p);
+    END LOOP;
+
+    -- RAISE DEBUG 'Tables: %', tables;
+
+  END LOOP;
+
+  -- RAISE DEBUG 'Tables: %', tables;
+
+  -- Remove duplicates and sort by name
+  IF array_upper(tables, 1) > 0 THEN
+    WITH dist as ( SELECT DISTINCT unnest(tables)::text as p ORDER BY p )
+       SELECT array_agg(p) from dist into tables;
+  END IF;
+
+  --RAISE DEBUG 'Tables: %', tables;
+
+  return tables;
+END
+$$ LANGUAGE 'plpgsql' VOLATILE STRICT;