Fix segfault on CAggs with multiple JOINs

Creating or changing to realtime a Continuous Aggregate with multiple
joins was leading to a segfault.

Fixed it by dealing properly with the `varno` when creating the `Quals`
for the union view in realtime mode.

Also get rid of some left over when we relaxed the CAggs joint
restrictions in timescale#7111

tsl/src/continuous_aggs/common.c

@@ -1332,55 +1332,27 @@ build_union_query(CAggTimebucketInfo *tbinfo, int matpartcolno, Query *q1, Query
 	/*
 	 * If there is join in CAgg definition then adjust varno
 	 * to get time column from the hypertable in the join.
-	 *
-	 * In case of joins it is enough to check if the first node is not RangeTblRef,
-	 * because the jointree has RangeTblRef as leaves and JoinExpr above them.
-	 * So if JoinExpr is present, it is the first node.
-	 * Other cases of join i.e. without explicit JOIN clause is confirmed
-	 * by reading the length of rtable.
 	 */
-	if (list_length(q2->rtable) == CONTINUOUS_AGG_MAX_JOIN_RELATIONS ||
-		!IsA(linitial(q2->jointree->fromlist), RangeTblRef))
-	{
-		Oid normal_table_id = InvalidOid;
-		RangeTblEntry *rte = NULL;
-		RangeTblEntry *rte_other = NULL;
+	varno = list_length(q2->rtable);
 
-		if (list_length(q2->rtable) == CONTINUOUS_AGG_MAX_JOIN_RELATIONS)
-		{
-			RangeTblRef *rtref = linitial_node(RangeTblRef, q2->jointree->fromlist);
-			rte = list_nth(q2->rtable, rtref->rtindex - 1);
-			RangeTblRef *rtref_other = lsecond_node(RangeTblRef, q2->jointree->fromlist);
-			rte_other = list_nth(q2->rtable, rtref_other->rtindex - 1);
-		}
-		else if (!IsA(linitial(q2->jointree->fromlist), RangeTblRef))
+	if (list_length(q2->rtable) > 1 || !IsA(linitial(q2->jointree->fromlist), RangeTblRef))
+	{
+		int nvarno = 1;
+		foreach (lc2, q2->rtable)
 		{
-			ListCell *l;
-			foreach (l, q2->jointree->fromlist)
+			RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc2);
+			if (rte->rtekind == RTE_RELATION)
 			{
-				Node *jtnode = (Node *) lfirst(l);
-				JoinExpr *join = NULL;
-				if (IsA(jtnode, JoinExpr))
+				/* look for hypertable in the list of RangeTableEntry */
+				if (rte->relid == tbinfo->htoid)
 				{
-					join = castNode(JoinExpr, jtnode);
-					rte = list_nth(q2->rtable, ((RangeTblRef *) join->larg)->rtindex - 1);
-					rte_other = list_nth(q2->rtable, ((RangeTblRef *) join->rarg)->rtindex - 1);
+					varno = nvarno;
+					break;
 				}
 			}
+			nvarno++;
 		}
-		if (rte->relkind == RELKIND_VIEW)
-			normal_table_id = rte_other->relid;
-		else if (rte_other->relkind == RELKIND_VIEW)
-			normal_table_id = rte->relid;
-		else
-			normal_table_id = ts_is_hypertable(rte->relid) ? rte_other->relid : rte->relid;
-		if (normal_table_id == rte->relid)
-			varno = 2;
-		else
-			varno = 1;
 	}
-	else
-		varno = list_length(q2->rtable);
 
 	q2_quals = build_union_query_quals(materialize_htid,
 									   tbinfo->htpartcoltype,

tsl/src/continuous_aggs/common.h

@@ -36,7 +36,6 @@
 #include "ts_catalog/catalog.h"
 #include "ts_catalog/continuous_agg.h"
 
-#define CONTINUOUS_AGG_MAX_JOIN_RELATIONS 2
 #define DEFAULT_MATPARTCOLUMN_NAME "time_partition_col"
 #define CAGG_INVALIDATION_THRESHOLD_NAME "invalidation threshold watermark"
 

tsl/src/continuous_aggs/finalize.c

@@ -149,8 +149,7 @@ finalizequery_get_select_query(FinalizeQueryInfo *inp, List *matcollist,
 	 * which contains the information of the materialised hypertable
 	 * that is created for this cagg.
 	 */
-	if (list_length(inp->final_userquery->jointree->fromlist) >=
-			CONTINUOUS_AGG_MAX_JOIN_RELATIONS ||
+	if (list_length(inp->final_userquery->jointree->fromlist) > 1 ||
 		!IsA(linitial(inp->final_userquery->jointree->fromlist), RangeTblRef))
 	{
 		rte = makeNode(RangeTblEntry);
@@ -259,8 +258,7 @@ finalizequery_get_select_query(FinalizeQueryInfo *inp, List *matcollist,
 		}
 	}
 
-	if (list_length(inp->final_userquery->jointree->fromlist) >=
-			CONTINUOUS_AGG_MAX_JOIN_RELATIONS ||
+	if (list_length(inp->final_userquery->jointree->fromlist) > 1 ||
 		!IsA(linitial(inp->final_userquery->jointree->fromlist), RangeTblRef))
 	{
 		RangeTblRef *rtr;
@@ -290,15 +288,10 @@ finalizequery_get_select_query(FinalizeQueryInfo *inp, List *matcollist,
 	 * we can not copy the fromlist from inp->final_userquery as
 	 * it has two tables in this case.
 	 */
-	Assert(list_length(inp->final_userquery->jointree->fromlist) <=
-		   CONTINUOUS_AGG_MAX_JOIN_RELATIONS);
-
 	final_selquery->jointree = fromexpr;
 	final_selquery->targetList = inp->final_seltlist;
 	final_selquery->sortClause = inp->final_userquery->sortClause;
 
-	/* Already finalized query no need to copy group by or having clause. */
-
 	return final_selquery;
 }
 

tsl/test/expected/cagg_joins.out

@@ -1165,6 +1165,53 @@ JOIN location ON location.name = devices.location
 GROUP BY bucket, devices.name, location.name;
 NOTICE:  refreshing continuous aggregate "conditions_by_day"
 HINT:  Use WITH NO DATA if you do not want to refresh the continuous aggregate on creation.
+SELECT * FROM conditions_by_day ORDER BY bucket, device, location;
+            bucket            |         avg         |  device  | location  
+------------------------------+---------------------+----------+-----------
+ Sun Jun 13 17:00:00 2021 PDT | 26.0000000000000000 | thermo_1 | Moscow
+ Mon Jun 14 17:00:00 2021 PDT | 22.0000000000000000 | thermo_2 | Berlin
+ Tue Jun 15 17:00:00 2021 PDT | 24.0000000000000000 | thermo_3 | London
+ Wed Jun 16 17:00:00 2021 PDT | 24.0000000000000000 | thermo_4 | Stockholm
+ Thu Jun 17 17:00:00 2021 PDT | 27.0000000000000000 | thermo_4 | Stockholm
+ Fri Jun 18 17:00:00 2021 PDT | 28.0000000000000000 | thermo_4 | Stockholm
+ Sat Jun 19 17:00:00 2021 PDT | 30.0000000000000000 | thermo_1 | Moscow
+ Sun Jun 20 17:00:00 2021 PDT | 31.0000000000000000 | thermo_1 | Moscow
+ Mon Jun 21 17:00:00 2021 PDT | 34.0000000000000000 | thermo_1 | Moscow
+ Tue Jun 22 17:00:00 2021 PDT | 34.0000000000000000 | thermo_2 | Berlin
+ Wed Jun 23 17:00:00 2021 PDT | 34.0000000000000000 | thermo_2 | Berlin
+ Thu Jun 24 17:00:00 2021 PDT | 32.0000000000000000 | thermo_3 | London
+ Fri Jun 25 17:00:00 2021 PDT | 32.0000000000000000 | thermo_3 | London
+ Sat Jun 26 17:00:00 2021 PDT | 31.0000000000000000 | thermo_3 | London
+ Tue Jun 29 17:00:00 2021 PDT | 28.0000000000000000 | thermo_3 | London
+ Wed Jun 30 17:00:00 2021 PDT | 28.0000000000000000 | thermo_3 | London
+(16 rows)
+
+ALTER MATERIALIZED VIEW conditions_by_day SET (timescaledb.materialized_only = FALSE);
+-- Insert one more row on conditions and check the count
+INSERT INTO conditions (day, city, temperature, device_id) VALUES
+  ('2024-07-01', 'Moscow', 28, 3);
+SELECT * FROM conditions_by_day ORDER BY bucket, device, location;
+            bucket            |         avg         |  device  | location  
+------------------------------+---------------------+----------+-----------
+ Sun Jun 13 17:00:00 2021 PDT | 26.0000000000000000 | thermo_1 | Moscow
+ Mon Jun 14 17:00:00 2021 PDT | 22.0000000000000000 | thermo_2 | Berlin
+ Tue Jun 15 17:00:00 2021 PDT | 24.0000000000000000 | thermo_3 | London
+ Wed Jun 16 17:00:00 2021 PDT | 24.0000000000000000 | thermo_4 | Stockholm
+ Thu Jun 17 17:00:00 2021 PDT | 27.0000000000000000 | thermo_4 | Stockholm
+ Fri Jun 18 17:00:00 2021 PDT | 28.0000000000000000 | thermo_4 | Stockholm
+ Sat Jun 19 17:00:00 2021 PDT | 30.0000000000000000 | thermo_1 | Moscow
+ Sun Jun 20 17:00:00 2021 PDT | 31.0000000000000000 | thermo_1 | Moscow
+ Mon Jun 21 17:00:00 2021 PDT | 34.0000000000000000 | thermo_1 | Moscow
+ Tue Jun 22 17:00:00 2021 PDT | 34.0000000000000000 | thermo_2 | Berlin
+ Wed Jun 23 17:00:00 2021 PDT | 34.0000000000000000 | thermo_2 | Berlin
+ Thu Jun 24 17:00:00 2021 PDT | 32.0000000000000000 | thermo_3 | London
+ Fri Jun 25 17:00:00 2021 PDT | 32.0000000000000000 | thermo_3 | London
+ Sat Jun 26 17:00:00 2021 PDT | 31.0000000000000000 | thermo_3 | London
+ Tue Jun 29 17:00:00 2021 PDT | 28.0000000000000000 | thermo_3 | London
+ Wed Jun 30 17:00:00 2021 PDT | 28.0000000000000000 | thermo_3 | London
+ Sun Jun 30 17:00:00 2024 PDT | 28.0000000000000000 | thermo_3 | London
+(17 rows)
+
 -- JOIN with a foreign table
 \c :TEST_DBNAME :ROLE_SUPERUSER
 SELECT current_setting('port') AS "PGPORT", current_database() AS "PGDATABASE" \gset

tsl/test/sql/cagg_joins.sql

@@ -564,6 +564,16 @@ JOIN devices ON conditions.device_id = devices.device_id
 JOIN location ON location.name = devices.location
 GROUP BY bucket, devices.name, location.name;
 
+SELECT * FROM conditions_by_day ORDER BY bucket, device, location;
+
+ALTER MATERIALIZED VIEW conditions_by_day SET (timescaledb.materialized_only = FALSE);
+
+-- Insert one more row on conditions and check the count
+INSERT INTO conditions (day, city, temperature, device_id) VALUES
+  ('2024-07-01', 'Moscow', 28, 3);
+
+SELECT * FROM conditions_by_day ORDER BY bucket, device, location;
+
 -- JOIN with a foreign table
 \c :TEST_DBNAME :ROLE_SUPERUSER
 SELECT current_setting('port') AS "PGPORT", current_database() AS "PGDATABASE" \gset