Fix creation of ordered projections

Author: knizhnik

sql/test.sql

@@ -31,3 +31,30 @@ select vit_refresh();
 select * from vit;
 select count(*) from vit where t='min'::text;
 select count(*) from vit where i>='1 minute'::interval;
+
+create table stock(symbol char(5), day date, low real, high real, open real, close real);
+insert into stock values
+('AAA', '01-11-2018', 10.0, 11.0, 10.1, 10.8),
+('AAA', '02-11-2018', 11.0, 12.0, 11.2, 11.5),
+('AAA', '03-11-2018', 10.4, 10.6, 10.5, 10.4),
+('AAA', '04-11-2018', 11.1, 11.5, 11.2, 11.4),
+('AAA', '05-11-2018', 11.0, 11.3, 11.4, 11.1);
+select create_projection('vstock','stock',array['day','low','high','open','close'],array['symbol'],'day');
+
+select vstock_refresh();
+select avg((open+close)/2),max(high-low) from stock group by day;
+set vops.auto_substitute_projections=on;
+explain (costs off) select avg((open+close)/2),max(high-low) from stock group by day;
+select avg((open+close)/2),max(high-low) from stock group by day;
+
+insert into stock values
+('AAA', '06-11-2018', 10.1, 10.8, 10.3, 10.2),
+('AAA', '07-11-2018', 11.1, 11.8, 10.2, 11.4),
+('AAA', '08-11-2018', 11.2, 11.6, 11.4, 11.3),
+('AAA', '09-11-2018', 10.6, 11.1, 11.3, 10.8),
+('AAA', '10-11-2018', 10.7, 11.3, 10.8, 11.1);
+select vstock_refresh();
+
+select avg((open+close)/2),max(high-low) from stock group by day;
+set vops.auto_substitute_projections=off;
+select avg((open+close)/2),max(high-low) from stock group by day;

vops--1.0.sql

@@ -3197,7 +3197,7 @@ declare
 		sep := ',';
 		if att_name=order_by
 		then
-			key_type = typname;
+			key_type := att_typname;
 		end if;
 	end loop;
 
@@ -3222,7 +3222,7 @@ declare
  	    execute create_index;
 		if key_type='timestamp' or key_type='date'
 		then
-		    min_value := '''-infinity''';
+		    min_value := '''''-infinity''''::'||key_type;
 		else
 			min_value := '-1'; -- assume that key have only non-negative values
 		end if;

vops.c

@@ -1932,7 +1932,7 @@ Datum vops_populate(PG_FUNCTION_ARGS)
         Oid type_id = DatumGetObjectId(SPI_getbinval(spi_tuple, spi_tupdesc, 2, &is_null));
 		types[i].tid = vops_get_type(type_id);
 		get_typlenbyvalalign(type_id, &types[i].len, &types[i].byval, &types[i].align);
-		if (types[i].len < 0) { /* varying length type: extract size from atttypmod */
+		if (types[i].tid != VOPS_LAST && types[i].len < 0) { /* varying length type: extract size from atttypmod */
 			types[i].len = DatumGetInt32(SPI_getbinval(spi_tuple, spi_tupdesc, 3, &is_null)) - VARHDRSZ;
 			if (types[i].len < 0) {
 				elog(ERROR, "Size of column %s is unknown", name);

vops.html

@@ -819,6 +819,11 @@ <h2><a name="projections">Table projections</a></h2>
   <li>Query performs aggregation of vector (tile) columns.</li>
   <li>All other expressions in target list, <code>ORDER BY</code> / <code>GROUP BY</code> clauses refers only to scalar attributes of projection.</li>
 </ul>
+<p>
+  Projection can be removed using <code>drop_projection(projection_name text)</code> function.
+  It not only drops the correspondent table, but also remove information about it from <code>vops_partitions</code> table
+  and drops generated refresh function.
+</p>
 
 
 <h2><a name="example">Example</a></h2>