Verify compression configuration on compression rollup

Add a check to verify compression settings for chunks to be rolled
up are identical.

src/ts_catalog/array_utils.c

@@ -4,10 +4,14 @@
  * LICENSE-APACHE for a copy of the license.
  */
 #include <postgres.h>
+#include <catalog/pg_collation.h>
 #include <catalog/pg_type.h>
+#include <fmgr.h>
 #include <utils/array.h>
 #include <utils/builtins.h>
+#include <utils/fmgroids.h>
 
+#include <compat/compat.h>
 #include <debug_assert.h>
 #include "array_utils.h"
 
@@ -29,6 +33,26 @@ ts_array_length(ArrayType *arr)
 	return ARR_DIMS(arr)[0];
 }
 
+extern TSDLLEXPORT bool
+ts_array_equal(ArrayType *left, ArrayType *right)
+{
+	/* Quick exit if both are NULL or point to same thing. */
+	if (left == right)
+		return true;
+
+	if (left == NULL || right == NULL)
+		return false;
+
+	Assert(left != NULL && right != NULL && ARR_NDIM(left) == 1 && ARR_NDIM(right) == 1);
+
+	Datum result = OidFunctionCall2Coll(F_ARRAY_EQ,
+										DEFAULT_COLLATION_OID,
+										PointerGetDatum(left),
+										PointerGetDatum(right));
+
+	return DatumGetBool(result);
+}
+
 extern TSDLLEXPORT bool
 ts_array_is_member(ArrayType *arr, const char *name)
 {

src/ts_catalog/array_utils.h

@@ -18,6 +18,7 @@
  */
 
 extern TSDLLEXPORT int ts_array_length(ArrayType *arr);
+extern TSDLLEXPORT bool ts_array_equal(ArrayType *left, ArrayType *right);
 extern TSDLLEXPORT bool ts_array_is_member(ArrayType *arr, const char *name);
 extern TSDLLEXPORT int ts_array_position(ArrayType *arr, const char *name);
 

src/ts_catalog/compression_settings.c

@@ -19,6 +19,15 @@ static ScanTupleResult compression_settings_tuple_update(TupleInfo *ti, void *da
 static HeapTuple compression_settings_formdata_make_tuple(const FormData_compression_settings *fd,
 														  TupleDesc desc);
 
+bool
+ts_compression_settings_equal(const CompressionSettings *left, const CompressionSettings *right)
+{
+	return ts_array_equal(left->fd.segmentby, right->fd.segmentby) &&
+		   ts_array_equal(left->fd.orderby, right->fd.orderby) &&
+		   ts_array_equal(left->fd.orderby_desc, right->fd.orderby_desc) &&
+		   ts_array_equal(left->fd.orderby_nullsfirst, right->fd.orderby_nullsfirst);
+}
+
 CompressionSettings *
 ts_compression_settings_materialize(Oid ht_relid, Oid dst_relid)
 {

src/ts_catalog/compression_settings.h

@@ -23,6 +23,8 @@ TSDLLEXPORT CompressionSettings *ts_compression_settings_create(Oid relid, Array
 TSDLLEXPORT CompressionSettings *ts_compression_settings_get(Oid relid);
 TSDLLEXPORT CompressionSettings *ts_compression_settings_materialize(Oid ht_relid, Oid dst_relid);
 TSDLLEXPORT bool ts_compression_settings_delete(Oid relid);
+TSDLLEXPORT bool ts_compression_settings_equal(const CompressionSettings *left,
+											   const CompressionSettings *right);
 
 TSDLLEXPORT int ts_compression_settings_update(CompressionSettings *settings);
 

tsl/src/compression/api.c

@@ -385,6 +385,13 @@ find_chunk_to_merge_into(Hypertable *ht, Chunk *current_chunk)
 		compressed_chunk_interval + current_chunk_interval > max_chunk_interval)
 		return NULL;
 
+	/* Get reloid of the previous compressed chunk */
+	Oid prev_comp_reloid = ts_chunk_get_relid(previous_chunk->fd.compressed_chunk_id, false);
+	CompressionSettings *prev_comp_settings = ts_compression_settings_get(prev_comp_reloid);
+	CompressionSettings *ht_comp_settings = ts_compression_settings_get(ht->main_table_relid);
+	if (!ts_compression_settings_equal(ht_comp_settings, prev_comp_settings))
+		return NULL;
+
 	return previous_chunk;
 }
 

tsl/test/expected/compression_merge.out

@@ -659,3 +659,132 @@ SELECT count(*) FROM test8 WHERE series_id = 1;
    481
 (1 row)
 
+-- Verify rollup is prevented when compression settings differ
+CREATE TABLE test9(time TIMESTAMPTZ NOT NULL, value DOUBLE PRECISION NOT NULL, series_id BIGINT NOT NULL);
+SELECT create_hypertable('test9', 'time', chunk_time_interval => INTERVAL '1 h');
+  create_hypertable  
+---------------------
+ (17,public,test9,t)
+(1 row)
+
+ALTER TABLE test9 set (timescaledb.compress,
+    timescaledb.compress_segmentby = 'series_id',
+    timescaledb.compress_orderby = 'time',
+    timescaledb.compress_chunk_time_interval = '1 day');
+-- create chunk and compress
+INSERT INTO test9 (time, series_id, value) SELECT '2020-01-01 00:00:00'::TIMESTAMPTZ, 1, 1;
+SELECT compress_chunk(show_chunks('test9'), true);
+              compress_chunk               
+-------------------------------------------
+ _timescaledb_internal._hyper_17_320_chunk
+(1 row)
+
+INSERT INTO test9 (time, series_id, value) SELECT '2020-01-01 01:00:00'::TIMESTAMPTZ, 1, 1;
+-- should be 2 chunk before rollup
+SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 01:00:00 2020 PST
+ test9           | Wed Jan 01 01:00:00 2020 PST | Wed Jan 01 02:00:00 2020 PST
+(2 rows)
+
+SELECT compress_chunk(show_chunks('test9'), true);
+NOTICE:  chunk "_hyper_17_320_chunk" is already compressed
+              compress_chunk               
+-------------------------------------------
+ _timescaledb_internal._hyper_17_320_chunk
+ _timescaledb_internal._hyper_17_320_chunk
+(2 rows)
+
+-- should be 1 chunk because of rollup
+SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 02:00:00 2020 PST
+(1 row)
+
+INSERT INTO test9 (time, series_id, value) SELECT '2020-01-01 02:00:00'::TIMESTAMPTZ, 1, 1;
+-- should be 2 chunks again
+SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 02:00:00 2020 PST
+ test9           | Wed Jan 01 02:00:00 2020 PST | Wed Jan 01 03:00:00 2020 PST
+(2 rows)
+
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = '');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+NOTICE:  chunk "_hyper_17_320_chunk" is already compressed
+              compress_chunk               
+-------------------------------------------
+ _timescaledb_internal._hyper_17_320_chunk
+ _timescaledb_internal._hyper_17_323_chunk
+(2 rows)
+
+  -- should not be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 02:00:00 2020 PST
+ test9           | Wed Jan 01 02:00:00 2020 PST | Wed Jan 01 03:00:00 2020 PST
+(2 rows)
+
+ROLLBACK;
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = 'series_id', timescaledb.compress_orderby = 'time DESC');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+NOTICE:  chunk "_hyper_17_320_chunk" is already compressed
+              compress_chunk               
+-------------------------------------------
+ _timescaledb_internal._hyper_17_320_chunk
+ _timescaledb_internal._hyper_17_323_chunk
+(2 rows)
+
+  -- should not be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 02:00:00 2020 PST
+ test9           | Wed Jan 01 02:00:00 2020 PST | Wed Jan 01 03:00:00 2020 PST
+(2 rows)
+
+ROLLBACK;
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = 'series_id', timescaledb.compress_orderby = 'time NULLS FIRST');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+NOTICE:  chunk "_hyper_17_320_chunk" is already compressed
+              compress_chunk               
+-------------------------------------------
+ _timescaledb_internal._hyper_17_320_chunk
+ _timescaledb_internal._hyper_17_323_chunk
+(2 rows)
+
+  -- should not be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 02:00:00 2020 PST
+ test9           | Wed Jan 01 02:00:00 2020 PST | Wed Jan 01 03:00:00 2020 PST
+(2 rows)
+
+ROLLBACK;
+-- reset back to original settings
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = 'series_id', timescaledb.compress_orderby = 'time');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+NOTICE:  chunk "_hyper_17_320_chunk" is already compressed
+              compress_chunk               
+-------------------------------------------
+ _timescaledb_internal._hyper_17_320_chunk
+ _timescaledb_internal._hyper_17_320_chunk
+(2 rows)
+
+  -- should be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ hypertable_name |         range_start          |          range_end           
+-----------------+------------------------------+------------------------------
+ test9           | Wed Jan 01 00:00:00 2020 PST | Wed Jan 01 03:00:00 2020 PST
+(1 row)
+
+ROLLBACK;

tsl/test/sql/compression_merge.sql

@@ -233,3 +233,57 @@ SET enable_seqscan TO OFF;
 SET enable_bitmapscan TO ON;
 
 SELECT count(*) FROM test8 WHERE series_id = 1;
+
+-- Verify rollup is prevented when compression settings differ
+CREATE TABLE test9(time TIMESTAMPTZ NOT NULL, value DOUBLE PRECISION NOT NULL, series_id BIGINT NOT NULL);
+SELECT create_hypertable('test9', 'time', chunk_time_interval => INTERVAL '1 h');
+
+ALTER TABLE test9 set (timescaledb.compress,
+    timescaledb.compress_segmentby = 'series_id',
+    timescaledb.compress_orderby = 'time',
+    timescaledb.compress_chunk_time_interval = '1 day');
+
+-- create chunk and compress
+INSERT INTO test9 (time, series_id, value) SELECT '2020-01-01 00:00:00'::TIMESTAMPTZ, 1, 1;
+SELECT compress_chunk(show_chunks('test9'), true);
+INSERT INTO test9 (time, series_id, value) SELECT '2020-01-01 01:00:00'::TIMESTAMPTZ, 1, 1;
+
+-- should be 2 chunk before rollup
+SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+SELECT compress_chunk(show_chunks('test9'), true);
+-- should be 1 chunk because of rollup
+SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+
+INSERT INTO test9 (time, series_id, value) SELECT '2020-01-01 02:00:00'::TIMESTAMPTZ, 1, 1;
+-- should be 2 chunks again
+SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = '');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+  -- should not be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ROLLBACK;
+
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = 'series_id', timescaledb.compress_orderby = 'time DESC');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+  -- should not be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ROLLBACK;
+
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = 'series_id', timescaledb.compress_orderby = 'time NULLS FIRST');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+  -- should not be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ROLLBACK;
+
+-- reset back to original settings
+ALTER TABLE test9 SET (timescaledb.compress_segmentby = 'series_id', timescaledb.compress_orderby = 'time');
+BEGIN;
+  SELECT compress_chunk(show_chunks('test9'), true);
+  -- should be rolled up
+  SELECT hypertable_name, range_start, range_end FROM timescaledb_information.chunks WHERE hypertable_name = 'test9' ORDER BY 2;
+ROLLBACK;
+