Add default index for continuous aggregates

Add indexes for materialization table created by continuous aggregates.
This behavior can be turned on/off by using timescaledb.create_group_indexes parameter
of the WITH clause when the continuous agg is created.

src/continuous_agg.c

@@ -50,6 +50,11 @@ static const WithClauseDefinition continuous_aggregate_with_clause_def[] = {
 			.arg_name = "max_interval_per_job",
 			.type_id = TEXTOID,
 		},
+		[ContinuousViewOptionCreateGroupIndex] = {
+			.arg_name = "create_group_indexes",
+			.type_id = BOOLOID,
+			.default_val = BoolGetDatum(true),
+		},
 };
 
 WithClauseResult *

src/continuous_agg.h

@@ -22,6 +22,7 @@ typedef enum ContinuousAggViewOption
 	ContinuousViewOptionRefreshLag,
 	ContinuousViewOptionRefreshInterval,
 	ContinuousViewOptionMaxIntervalPerRun,
+	ContinuousViewOptionCreateGroupIndex,
 } ContinuousAggViewOption;
 
 typedef enum ContinuousAggViewType

tsl/src/continuous_aggs/create.c

@@ -19,12 +19,15 @@
 #include <nodes/parsenodes.h>
 #include <nodes/makefuncs.h>
 #include <nodes/nodeFuncs.h>
+#include <catalog/index.h>
 #include <catalog/pg_type.h>
 #include <catalog/pg_aggregate.h>
 #include <catalog/toasting.h>
 #include <catalog/pg_collation.h>
 #include <catalog/pg_trigger.h>
+#include <commands/defrem.h>
 #include <commands/tablecmds.h>
+#include <commands/tablespace.h>
 #include <commands/trigger.h>
 #include <commands/view.h>
 #include <access/xact.h>
@@ -135,8 +138,12 @@ typedef struct MatTableColumnInfo
 	List *matcollist;		 /* column defns for materialization tbl*/
 	List *partial_seltlist;  /* tlist entries for populating the materialization table columns */
 	List *partial_grouplist; /* group clauses used for populating the materialization table */
-	int matpartcolno;		 /*index of partitioning column in matcollist */
+	List *mat_groupcolname_list; /* names of columns that are populated by the group-by clause
-	char *matpartcolname;	/*name of the partition column */
+									correspond to the partial_grouplist.
+									time_bucket column is not included here: it is the
+									matpartcolname */
+	int matpartcolno;			 /*index of partitioning column in matcollist */
+	char *matpartcolname;		 /*name of the partition column */
 } MatTableColumnInfo;
 
 typedef struct FinalizeQueryInfo
@@ -178,6 +185,7 @@ static void mattablecolumninfo_addinternal(MatTableColumnInfo *matcolinfo,
 static int32 mattablecolumninfo_create_materialization_table(MatTableColumnInfo *matcolinfo,
 															 int32 hypertable_id, RangeVar *mat_rel,
 															 CAggTimebucketInfo *origquery_tblinfo,
+															 bool create_addl_index,
 															 ObjectAddress *mataddress);
 static Query *mattablecolumninfo_get_partial_select_query(MatTableColumnInfo *matcolinfo,
 														  Query *userview_query);
@@ -317,6 +325,58 @@ cagg_add_trigger_hypertable(Oid relid, char *trigarg)
 	ts_cache_release(hcache);
 }
 
+/* add additional indexes to materialization table for the columns derived from
+ * the group-by column list of the partial select query
+ * if partial select query has:
+ * GROUP BY timebucket_expr, <grpcol1, grpcol2, grpcol3 ...>
+ * index on mattable is <grpcol1, timebucketcol>, <grpcol2, timebucketcol> ... and so on.
+ * i.e. #indexes =(  #grp-cols - 1)
+ */
+static void
+mattablecolumninfo_add_mattable_index(MatTableColumnInfo *matcolinfo, Hypertable *ht)
+{
+	IndexStmt stmt = {
+		.type = T_IndexStmt,
+		.accessMethod = DEFAULT_INDEX_TYPE,
+		.idxname = NULL,
+		.relation = makeRangeVar(NameStr(ht->fd.schema_name), NameStr(ht->fd.table_name), 0),
+		.tableSpace = get_tablespace_name(get_rel_tablespace(ht->main_table_relid)),
+	};
+	IndexElem timeelem = { .type = T_IndexElem,
+						   .name = matcolinfo->matpartcolname,
+						   .ordering = SORTBY_DESC };
+	ListCell *le = NULL;
+	foreach (le, matcolinfo->mat_groupcolname_list)
+	{
+		NameData indxname;
+		ObjectAddress indxaddr;
+		HeapTuple indxtuple;
+		char *grpcolname = (char *) lfirst(le);
+		IndexElem grpelem = { .type = T_IndexElem, .name = grpcolname };
+		stmt.indexParams = list_make2(&grpelem, &timeelem);
+		indxaddr = DefineIndexCompat(ht->main_table_relid,
+									 &stmt,
+									 InvalidOid,
+									 false,  /* is alter table */
+									 false,  /* check rights */
+									 false,  /* skip_build */
+									 false); /* quiet */
+		indxtuple = SearchSysCache1(RELOID, ObjectIdGetDatum(indxaddr.objectId));
+
+		if (!HeapTupleIsValid(indxtuple))
+			elog(ERROR, "cache lookup failed for index relid %d", indxaddr.objectId);
+		indxname = ((Form_pg_class) GETSTRUCT(indxtuple))->relname;
+		elog(NOTICE,
+			 "adding index %s ON %s.%s USING BTREE(%s, %s)",
+			 NameStr(indxname),
+			 NameStr(ht->fd.schema_name),
+			 NameStr(ht->fd.table_name),
+			 grpcolname,
+			 matcolinfo->matpartcolname);
+		ReleaseSysCache(indxtuple);
+	}
+}
+
 /*
  * Create the materialization hypertable root by faking up a
  * CREATE TABLE parsetree and passing it to DefineRelation.
@@ -333,7 +393,7 @@ static int32
 mattablecolumninfo_create_materialization_table(MatTableColumnInfo *matcolinfo, int32 hypertable_id,
 												RangeVar *mat_rel,
 												CAggTimebucketInfo *origquery_tblinfo,
-												ObjectAddress *mataddress)
+												bool create_addl_index, ObjectAddress *mataddress)
 {
 	Oid uid, saved_uid;
 	int sec_ctx;
@@ -379,6 +439,10 @@ mattablecolumninfo_create_materialization_table(MatTableColumnInfo *matcolinfo,
 	hcache = ts_hypertable_cache_pin();
 	ht = ts_hypertable_cache_get_entry(hcache, mat_relid);
 	mat_htid = ht->fd.id;
+
+	/* create additional index on the group-by columns for the materialization table */
+	if (create_addl_index)
+		mattablecolumninfo_add_mattable_index(matcolinfo, ht);
 	ts_cache_release(hcache);
 	return mat_htid;
 }
@@ -999,6 +1063,7 @@ mattablecolumninfo_init(MatTableColumnInfo *matcolinfo, List *collist, List *tli
 	matcolinfo->matcollist = collist;
 	matcolinfo->partial_seltlist = tlist;
 	matcolinfo->partial_grouplist = grouplist;
+	matcolinfo->mat_groupcolname_list = NIL;
 	matcolinfo->matpartcolno = -1;
 	matcolinfo->matpartcolname = NULL;
 }
@@ -1048,6 +1113,7 @@ mattablecolumninfo_addentry(MatTableColumnInfo *out, Node *input, int original_q
 		case T_TargetEntry:
 		{
 			TargetEntry *tle = (TargetEntry *) input;
+			bool timebkt_chk = false;
 			if (tle->resname)
 				colname = pstrdup(tle->resname);
 			else
@@ -1058,8 +1124,8 @@ mattablecolumninfo_addentry(MatTableColumnInfo *out, Node *input, int original_q
 			/* is this the time_bucket column */
 			if (IsA(tle->expr, FuncExpr))
 			{
-				bool chk = is_timebucket_expr(((FuncExpr *) tle->expr)->funcid);
+				timebkt_chk = is_timebucket_expr(((FuncExpr *) tle->expr)->funcid);
-				if (chk)
+				if (timebkt_chk)
 				{
 					colname = MATPARTCOLNM;
 					tle->resname = pstrdup(colname);
@@ -1067,6 +1133,10 @@ mattablecolumninfo_addentry(MatTableColumnInfo *out, Node *input, int original_q
 					out->matpartcolname = pstrdup(colname);
 				}
 			}
+			if (!timebkt_chk) /* add the names to the gorupcolname list */
+			{
+				out->mat_groupcolname_list = lappend(out->mat_groupcolname_list, pstrdup(colname));
+			}
 			coltype = exprType((Node *) tle->expr);
 			coltypmod = exprTypmod((Node *) tle->expr);
 			colcollation = exprCollation((Node *) tle->expr);
@@ -1518,6 +1588,7 @@ cagg_create(ViewStmt *stmt, Query *panquery, CAggTimebucketInfo *origquery_ht,
 	MatTableColumnInfo mattblinfo;
 	FinalizeQueryInfo finalqinfo;
 	CatalogSecurityContext sec_ctx;
+	bool is_create_mattbl_index;
 
 	Query *final_selquery;
 	Query *partial_selquery;	/* query to populate the mattable*/
@@ -1558,10 +1629,12 @@ cagg_create(ViewStmt *stmt, Query *panquery, CAggTimebucketInfo *origquery_ht,
 	ts_catalog_restore_user(&sec_ctx);
 	PRINT_MATINTERNAL_NAME(relnamebuf, "_materialized_hypertable_%d", materialize_hypertable_id);
 	mat_rel = makeRangeVar(pstrdup(INTERNAL_SCHEMA_NAME), pstrdup(relnamebuf), -1);
+	is_create_mattbl_index = with_clause_options[ContinuousViewOptionCreateGroupIndex].is_default;
 	mattablecolumninfo_create_materialization_table(&mattblinfo,
 													materialize_hypertable_id,
 													mat_rel,
 													origquery_ht,
+													is_create_mattbl_index,
 													&mataddress);
 	/* Step 2: create view with select finalize from materialization
 	 * table

tsl/src/continuous_aggs/options.c

@@ -198,4 +198,8 @@ continuous_agg_update_options(ContinuousAgg *agg, WithClauseResult *with_clause_
 			*DatumGetIntervalP(with_clause_options[ContinuousViewOptionRefreshInterval].parsed);
 		ts_bgw_job_update_by_id(agg->data.job_id, job);
 	}
+	if (!with_clause_options[ContinuousViewOptionCreateGroupIndex].is_default)
+	{
+		elog(ERROR, "cannot alter create_group_indexes option for continuous aggregates");
+	}
 }

tsl/test/expected/continuous_aggs.out

@@ -49,6 +49,7 @@ select a, count(b)
 from foo
 group by time_bucket(1, a), a;
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_2_a_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_2 USING BTREE(a, time_partition_col)
 SELECT * FROM _timescaledb_config.bgw_job;
   id  |          application_name           |       job_type       | schedule_interval | max_runtime | max_retries | retry_period 
 ------+-------------------------------------+----------------------+-------------------+-------------+-------------+--------------
@@ -514,6 +515,7 @@ SELECT
 \set ECHO errors
 psql:include/cont_agg_equal.sql:8: NOTICE:  drop cascades to 2 other objects
 psql:include/cont_agg_equal.sql:13: NOTICE:  adding not-null constraint to column "time_partition_col"
+psql:include/cont_agg_equal.sql:13: NOTICE:  adding index _materialized_hypertable_13_location_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_13 USING BTREE(location, time_partition_col)
                            ?column?                            | count 
 ---------------------------------------------------------------+-------
  Number of rows different between view and original (expect 0) |     0
@@ -756,8 +758,11 @@ WITH ( timescaledb.continuous, timescaledb.refresh_lag = '5 hours', timescaledb.
 as
 select time_bucket('1day', timec), min(location), sum(temperature),sum(humidity)
 from conditions
-group by time_bucket('1day', timec);
+group by time_bucket('1day', timec), location, humidity, temperature;
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_17_grp_5_5_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING BTREE(grp_5_5, time_partition_col)
+NOTICE:  adding index _materialized_hypertable_17_grp_6_6_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING BTREE(grp_6_6, time_partition_col)
+NOTICE:  adding index _materialized_hypertable_17_grp_7_7_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING BTREE(grp_7_7, time_partition_col)
 SELECT schedule_interval FROM _timescaledb_config.bgw_job;
  schedule_interval 
 -------------------
@@ -783,6 +788,39 @@ SELECT schedule_interval FROM _timescaledb_config.bgw_job;
  @ 2 hours
 (1 row)
 
+select indexname, indexdef from pg_indexes where tablename = 
+(SELECT h.table_name
+FROM _timescaledb_catalog.continuous_agg ca
+INNER JOIN _timescaledb_catalog.hypertable h ON(h.id = ca.mat_hypertable_id)
+WHERE user_view_name = 'mat_with_test')
+order by indexname;
+                         indexname                          |                                                                                  indexdef                                                                                   
+------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ _materialized_hypertable_17_grp_5_5_time_partition_col_idx | CREATE INDEX _materialized_hypertable_17_grp_5_5_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING btree (grp_5_5, time_partition_col DESC)
+ _materialized_hypertable_17_grp_6_6_time_partition_col_idx | CREATE INDEX _materialized_hypertable_17_grp_6_6_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING btree (grp_6_6, time_partition_col DESC)
+ _materialized_hypertable_17_grp_7_7_time_partition_col_idx | CREATE INDEX _materialized_hypertable_17_grp_7_7_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING btree (grp_7_7, time_partition_col DESC)
+ _materialized_hypertable_17_time_partition_col_idx         | CREATE INDEX _materialized_hypertable_17_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_17 USING btree (time_partition_col DESC)
+(4 rows)
+
+drop view mat_with_test cascade;
+--no additional indexes
+create or replace view mat_with_test( timec, minl, sumt , sumh)
+WITH ( timescaledb.continuous, timescaledb.refresh_lag = '5 hours', timescaledb.refresh_interval = '1h', timescaledb.create_group_indexes=false)
+as
+select time_bucket('1day', timec), min(location), sum(temperature),sum(humidity)
+from conditions
+group by time_bucket('1day', timec), location, humidity, temperature;
+NOTICE:  adding not-null constraint to column "time_partition_col"
+select indexname, indexdef from pg_indexes where tablename = 
+(SELECT h.table_name
+FROM _timescaledb_catalog.continuous_agg ca
+INNER JOIN _timescaledb_catalog.hypertable h ON(h.id = ca.mat_hypertable_id)
+WHERE user_view_name = 'mat_with_test');
+                     indexname                      |                                                                          indexdef                                                                          
+----------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------
+ _materialized_hypertable_18_time_partition_col_idx | CREATE INDEX _materialized_hypertable_18_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_18 USING btree (time_partition_col DESC)
+(1 row)
+
 DROP TABLE conditions CASCADE;
 NOTICE:  drop cascades to 2 other objects
 --test WITH using a hypertable with an integer time dimension
@@ -903,7 +941,7 @@ WARNING:  type integer text
 (3 rows)
 
 DROP view mat_ffunc_test cascade;
-NOTICE:  drop cascades to table _timescaledb_internal._hyper_21_61_chunk
+NOTICE:  drop cascades to table _timescaledb_internal._hyper_22_61_chunk
 create or replace view mat_ffunc_test
 WITH ( timescaledb.continuous, timescaledb.refresh_lag = '-200')
 as

tsl/test/expected/continuous_aggs_dump.out

@@ -99,6 +99,7 @@ CREATE VIEW mat_before
 WITH ( timescaledb.continuous, timescaledb.refresh_lag='-30 day')
 AS :QUERY_BEFORE;
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_3_location_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_3 USING BTREE(location, time_partition_col)
 --materialize this VIEW after dump this tests
 --that the partialize VIEW and refresh mechanics
 --survives the dump intact
@@ -106,6 +107,7 @@ CREATE VIEW mat_after
 WITH ( timescaledb.continuous, timescaledb.refresh_lag='-30 day')
 AS :QUERY_AFTER;
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_4_location_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_4 USING BTREE(location, time_partition_col)
 --materialize mat_before
 REFRESH MATERIALIZED VIEW mat_before;
 INFO:  new materialization range for public.conditions_before (time column timec) (1548633600000000)

tsl/test/expected/continuous_aggs_errors.out

@@ -370,6 +370,10 @@ INNER JOIN _timescaledb_catalog.hypertable h ON(h.id = ca.mat_hypertable_id)
 WHERE user_view_name = 'mat_with_test'
 \gset
 \set ON_ERROR_STOP 0
+ALTER VIEW mat_with_test SET(timescaledb.create_group_indexes = 'false');
+ERROR:  cannot alter create_group_indexes option for continuous aggregates
+ALTER VIEW mat_with_test SET(timescaledb.create_group_indexes = 'true');
+ERROR:  cannot alter create_group_indexes option for continuous aggregates
 ALTER VIEW mat_with_test SET(timescaledb.refresh_lag = '1 joule');
 ERROR:  invalid input syntax for type interval: "1 joule"
 ALTER VIEW mat_with_test RESET(timescaledb.refresh_lag);

tsl/test/expected/continuous_aggs_usage.out

@@ -40,6 +40,7 @@ FROM
   device_readings
 GROUP BY bucket, device_id; --We have to group by the bucket column, but can also add other group-by columns
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_2_device_id_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_2 USING BTREE(device_id, time_partition_col)
 --Next, insert some data into the raw hypertable
 INSERT INTO device_readings
 SELECT ts, 'device_1', (EXTRACT(EPOCH FROM ts)) from generate_series('2018-12-01 00:00'::timestamp, '2018-12-31 00:00'::timestamp, '30 minutes') ts;
@@ -237,6 +238,7 @@ FROM
   device_readings
 GROUP BY bucket, device_id;
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_3_device_id_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_3 USING BTREE(device_id, time_partition_col)
 DROP VIEW device_summary CASCADE;
 -- Option 2: Keep things as TIMESTAMPTZ in the view and convert to local time when
 -- querying from the view
@@ -255,6 +257,7 @@ FROM
   device_readings
 GROUP BY bucket, device_id;
 NOTICE:  adding not-null constraint to column "time_partition_col"
+NOTICE:  adding index _materialized_hypertable_4_device_id_time_partition_col_idx ON _timescaledb_internal._materialized_hypertable_4 USING BTREE(device_id, time_partition_col)
 REFRESH MATERIALIZED VIEW device_summary;
 INFO:  new materialization range for public.device_readings larger than allowed in one run, truncating (time column observation_time) (1546236000000000)
 INFO:  new materialization range for public.device_readings (time column observation_time) (1543723200000000)

tsl/test/sql/continuous_aggs.sql

@@ -558,7 +558,7 @@ WITH ( timescaledb.continuous, timescaledb.refresh_lag = '5 hours', timescaledb.
 as
 select time_bucket('1day', timec), min(location), sum(temperature),sum(humidity)
 from conditions
-group by time_bucket('1day', timec);
+group by time_bucket('1day', timec), location, humidity, temperature;
 
 SELECT schedule_interval FROM _timescaledb_config.bgw_job;
 SELECT _timescaledb_internal.to_interval(refresh_lag) FROM _timescaledb_catalog.continuous_agg WHERE user_view_name = 'mat_with_test';
@@ -567,6 +567,28 @@ ALTER VIEW mat_with_test SET(timescaledb.refresh_lag = '6 h', timescaledb.refres
 SELECT _timescaledb_internal.to_interval(refresh_lag) FROM _timescaledb_catalog.continuous_agg WHERE user_view_name = 'mat_with_test';
 SELECT schedule_interval FROM _timescaledb_config.bgw_job;
 
+select indexname, indexdef from pg_indexes where tablename = 
+(SELECT h.table_name
+FROM _timescaledb_catalog.continuous_agg ca
+INNER JOIN _timescaledb_catalog.hypertable h ON(h.id = ca.mat_hypertable_id)
+WHERE user_view_name = 'mat_with_test')
+order by indexname;
+
+drop view mat_with_test cascade;
+--no additional indexes
+create or replace view mat_with_test( timec, minl, sumt , sumh)
+WITH ( timescaledb.continuous, timescaledb.refresh_lag = '5 hours', timescaledb.refresh_interval = '1h', timescaledb.create_group_indexes=false)
+as
+select time_bucket('1day', timec), min(location), sum(temperature),sum(humidity)
+from conditions
+group by time_bucket('1day', timec), location, humidity, temperature;
+
+select indexname, indexdef from pg_indexes where tablename = 
+(SELECT h.table_name
+FROM _timescaledb_catalog.continuous_agg ca
+INNER JOIN _timescaledb_catalog.hypertable h ON(h.id = ca.mat_hypertable_id)
+WHERE user_view_name = 'mat_with_test');
+
 DROP TABLE conditions CASCADE;
 
 --test WITH using a hypertable with an integer time dimension

tsl/test/sql/continuous_aggs_errors.sql

@@ -367,6 +367,8 @@ WHERE user_view_name = 'mat_with_test'
 \gset
 
 \set ON_ERROR_STOP 0
+ALTER VIEW mat_with_test SET(timescaledb.create_group_indexes = 'false');
+ALTER VIEW mat_with_test SET(timescaledb.create_group_indexes = 'true');
 ALTER VIEW mat_with_test SET(timescaledb.refresh_lag = '1 joule');
 ALTER VIEW mat_with_test RESET(timescaledb.refresh_lag);
 ALTER VIEW mat_with_test ALTER timec DROP default;