Remove limitation of compression policy for continuous aggregates

Before compressed chunks were mutable, adding a compression policy
to a continuous aggregate that could include portions of the refrsh
window were blocked. When a continuous aggregate is refreshed, the
underlying chunks needed to allow DELETEs and INSERTs, so they
could not be compressed. Now, compressed chunks allow both operations
and there is no longer a need to prevent the refresh window and
compression window from overlapping.

.unreleased/pr_7656

@@ -0,0 +1 @@
+Implements: #7656 Remove limitation of compression policy for continuous aggregates

tsl/src/bgw_policy/compression_api.c

@@ -338,21 +338,6 @@ policy_compression_add_internal(Oid user_rel_oid, Datum compress_after_datum,
 							POL_COMPRESSION_CONF_KEY_COMPRESS_AFTER,
 							format_type_be(compress_after_type))));
 	}
-	/*
-	 * If this is a compression policy for a cagg, verify that
-	 * compress_after > refresh_start of cagg policy. We do not want
-	 * to compress regions that can be refreshed by the cagg policy.
-	 */
-	if (is_cagg && !policy_refresh_cagg_refresh_start_lt(hypertable->fd.id,
-														 compress_after_type,
-														 compress_after_datum))
-	{
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("compress_after value for compression policy should be greater than the "
-						"start of the refresh window of continuous aggregate policy for %s",
-						get_rel_name(user_rel_oid))));
-	}
 
 	JsonbValue *result = pushJsonbValue(&parse_state, WJB_END_OBJECT, NULL);
 	Jsonb *config = JsonbValueToJsonb(result);

tsl/test/expected/cagg_errors.out

@@ -595,14 +595,8 @@ ALTER MATERIALIZED VIEW i2980_cagg SET ( timescaledb.compress );
 NOTICE:  defaulting compress_orderby to time_bucket
 WARNING:  there was some uncertainty picking the default segment by for the hypertable: You do not have any indexes on columns that can be used for segment_by and thus we are not using segment_by for compression. Please make sure you are not missing any indexes
 NOTICE:  default segment by for hypertable "_materialized_hypertable_13" is set to ""
-SELECT add_compression_policy('i2980_cagg', '8 day'::interval);
-ERROR:  compress_after value for compression policy should be greater than the start of the refresh window of continuous aggregate policy for i2980_cagg
 SELECT add_continuous_aggregate_policy('i2980_cagg2', '10 day'::interval, '6 day'::interval);
 ERROR:  function add_continuous_aggregate_policy(unknown, interval, interval) does not exist at character 8
-SELECT add_compression_policy('i2980_cagg2', '3 day'::interval);
-ERROR:  compress_after value for compression policy should be greater than the start of the refresh window of continuous aggregate policy for i2980_cagg2
-SELECT add_compression_policy('i2980_cagg2', '1 day'::interval);
-ERROR:  compress_after value for compression policy should be greater than the start of the refresh window of continuous aggregate policy for i2980_cagg2
 SELECT add_compression_policy('i2980_cagg2', '3'::integer);
 ERROR:  unsupported compress_after argument type, expected type : interval
 SELECT add_compression_policy('i2980_cagg2', 13::integer);

tsl/test/expected/cagg_policy.out

@@ -1158,24 +1158,42 @@ ALTER MATERIALIZED VIEW mat_smallint SET (timescaledb.compress);
 NOTICE:  defaulting compress_orderby to a
 WARNING:  there was some uncertainty picking the default segment by for the hypertable: You do not have any indexes on columns that can be used for segment_by and thus we are not using segment_by for compression. Please make sure you are not missing any indexes
 NOTICE:  default segment by for hypertable "_materialized_hypertable_11" is set to ""
-\set ON_ERROR_STOP 0
-SELECT add_compression_policy('mat_smallint', 0::smallint);
-ERROR:  compress_after value for compression policy should be greater than the start of the refresh window of continuous aggregate policy for mat_smallint
+-- With immutable compressed chunks, these policies would fail by overlapping the refresh window
 SELECT add_compression_policy('mat_smallint', -4::smallint);
-ERROR:  compress_after value for compression policy should be greater than the start of the refresh window of continuous aggregate policy for mat_smallint
+ add_compression_policy 
+------------------------
+                   1053
+(1 row)
+
+SELECT remove_compression_policy('mat_smallint');
+ remove_compression_policy 
+---------------------------
+ t
+(1 row)
+
 SELECT add_compression_policy('mat_bigint', 0::bigint);
-ERROR:  compress_after value for compression policy should be greater than the start of the refresh window of continuous aggregate policy for mat_bigint
-\set ON_ERROR_STOP 1
+ add_compression_policy 
+------------------------
+                   1054
+(1 row)
+
+SELECT remove_compression_policy('mat_bigint');
+ remove_compression_policy 
+---------------------------
+ t
+(1 row)
+
+-- End previous limitation tests
 SELECT add_compression_policy('mat_smallint', 5::smallint);
  add_compression_policy 
 ------------------------
-                   1053
+                   1055
 (1 row)
 
 SELECT add_compression_policy('mat_bigint', 20::bigint);
  add_compression_policy 
 ------------------------
-                   1054
+                   1056
 (1 row)
 
 -- end of coverage tests
@@ -1227,7 +1245,7 @@ WITH NO DATA;
 SELECT add_continuous_aggregate_policy('metrics_cagg', '7 day'::interval, NULL, '1 h'::interval, if_not_exists => true);
  add_continuous_aggregate_policy 
 ---------------------------------
-                            1055
+                            1057
 (1 row)
 
 SELECT add_continuous_aggregate_policy('metrics_cagg', '7 day'::interval, '1 day'::interval, '1 h'::interval, if_not_exists => true);
@@ -1246,7 +1264,7 @@ SELECT remove_continuous_aggregate_policy('metrics_cagg');
 SELECT add_continuous_aggregate_policy('metrics_cagg', NULL, '1 day'::interval, '1h'::interval, if_not_exists=>true);
  add_continuous_aggregate_policy 
 ---------------------------------
-                            1056
+                            1058
 (1 row)
 
 SELECT add_continuous_aggregate_policy('metrics_cagg', NULL, '1 day'::interval, '1h'::interval, if_not_exists=>true); -- same param values, so we get a NOTICE
@@ -1287,7 +1305,7 @@ ERROR:  cannot use "compress_created_before" with continuous aggregate "metrics_
 SELECT add_compression_policy('metrics_cagg', '8 day'::interval) AS "COMP_JOB" ;
  COMP_JOB 
 ----------
-     1058
+     1060
 (1 row)
 
 SELECT remove_compression_policy('metrics_cagg');
@@ -1429,7 +1447,7 @@ SELECT set_integer_now_func('t', 'unix_now');
 SELECT add_retention_policy('t', 20);
  add_retention_policy 
 ----------------------
-                 1060
+                 1062
 (1 row)
 
 CREATE MATERIALIZED VIEW cagg(a, sumb) WITH (timescaledb.continuous)

tsl/test/sql/cagg_errors.sql

@@ -490,11 +490,8 @@ ALTER MATERIALIZED VIEW i2980_cagg2 SET ( timescaledb.compress, timescaledb.comp
 select add_continuous_aggregate_policy('i2980_cagg2', interval '10 day', interval '2 day' ,'4h') AS job_id ;
 SELECT add_compression_policy('i2980_cagg', '8 day'::interval);
 ALTER MATERIALIZED VIEW i2980_cagg SET ( timescaledb.compress );
-SELECT add_compression_policy('i2980_cagg', '8 day'::interval);
 
 SELECT add_continuous_aggregate_policy('i2980_cagg2', '10 day'::interval, '6 day'::interval);
-SELECT add_compression_policy('i2980_cagg2', '3 day'::interval);
-SELECT add_compression_policy('i2980_cagg2', '1 day'::interval);
 SELECT add_compression_policy('i2980_cagg2', '3'::integer);
 SELECT add_compression_policy('i2980_cagg2', 13::integer);
 

tsl/test/sql/cagg_policy.sql

@@ -505,11 +505,13 @@ SELECT * FROM mat_bigint WHERE a>100 ORDER BY 1;
 
 ALTER MATERIALIZED VIEW mat_bigint SET (timescaledb.compress);
 ALTER MATERIALIZED VIEW mat_smallint SET (timescaledb.compress);
-\set ON_ERROR_STOP 0
-SELECT add_compression_policy('mat_smallint', 0::smallint);
+-- With immutable compressed chunks, these policies would fail by overlapping the refresh window
 SELECT add_compression_policy('mat_smallint', -4::smallint);
+SELECT remove_compression_policy('mat_smallint');
 SELECT add_compression_policy('mat_bigint', 0::bigint);
-\set ON_ERROR_STOP 1
+SELECT remove_compression_policy('mat_bigint');
+-- End previous limitation tests
+
 SELECT add_compression_policy('mat_smallint', 5::smallint);
 SELECT add_compression_policy('mat_bigint', 20::bigint);