Mark Columnar Scan as CUSTOMPATH_SUPPORT_PROJECTION

tsl/src/nodes/columnar_scan/columnar_scan.c

@@ -2378,7 +2378,19 @@ columnar_scan_path_create(PlannerInfo *root, const CompressionInfo *compression_
 		path->custom_path.path.param_info = NULL;
 	}
 
-	path->custom_path.flags = 0;
+	/*
+	 * Setting this flags means that Postgres can change the result targetlist
+	 * after the plan creation. This node can cope with this because it performs
+	 * the usual Postgres projection to produce the result tuple from the scan
+	 * tuple. The decompression-specific code works before that, and produces
+	 * the scan tuple based on the compressed tuple. The scan tuple descriptor
+	 * is based either on custom_scan_tlist or scanrelid, and the decompression
+	 * map is based on the compressed tuple, so they are not dependent on the
+	 * result targetlist, and we can allow it to be changed later. This allows
+	 * us to avoid a separate Result node, for a small performance saving.
+	 */
+	path->custom_path.flags = CUSTOMPATH_SUPPORT_PROJECTION;
+
 	path->custom_path.methods = &columnar_scan_path_methods;
 	path->batch_sorted_merge = false;
 

tsl/test/expected/compress_sort_transform.out

@@ -227,28 +227,25 @@ order by 1 limit 1;
                Order: time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time")
                ->  Merge Append (actual rows=1.00 loops=1)
                      Sort Key: (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-                     ->  Result (actual rows=1.00 loops=1)
-                           ->  Custom Scan (ColumnarScan) on _hyper_1_1_chunk (actual rows=1.00 loops=1)
-                                 ->  Sort (actual rows=3.00 loops=1)
-                                       Sort Key: compress_hyper_2_4_chunk._ts_meta_min_1
-                                       Sort Method: quicksort 
-                                       ->  Seq Scan on compress_hyper_2_4_chunk (actual rows=3.00 loops=1)
+                     ->  Custom Scan (ColumnarScan) on _hyper_1_1_chunk (actual rows=1.00 loops=1)
+                           ->  Sort (actual rows=3.00 loops=1)
+                                 Sort Key: compress_hyper_2_4_chunk._ts_meta_min_1
+                                 Sort Method: quicksort 
+                                 ->  Seq Scan on compress_hyper_2_4_chunk (actual rows=3.00 loops=1)
                      ->  Index Scan Backward using _hyper_1_1_chunk_ht_metrics_partially_compressed_time_idx on _hyper_1_1_chunk (actual rows=1.00 loops=1)
                ->  Merge Append (never executed)
                      Sort Key: (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-                     ->  Result (never executed)
-                           ->  Custom Scan (ColumnarScan) on _hyper_1_2_chunk (never executed)
-                                 ->  Sort (never executed)
-                                       Sort Key: compress_hyper_2_5_chunk._ts_meta_min_1
-                                       ->  Seq Scan on compress_hyper_2_5_chunk (never executed)
+                     ->  Custom Scan (ColumnarScan) on _hyper_1_2_chunk (never executed)
+                           ->  Sort (never executed)
+                                 Sort Key: compress_hyper_2_5_chunk._ts_meta_min_1
+                                 ->  Seq Scan on compress_hyper_2_5_chunk (never executed)
                      ->  Index Scan Backward using _hyper_1_2_chunk_ht_metrics_partially_compressed_time_idx on _hyper_1_2_chunk (never executed)
                ->  Merge Append (never executed)
                      Sort Key: (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-                     ->  Result (never executed)
-                           ->  Custom Scan (ColumnarScan) on _hyper_1_3_chunk (never executed)
-                                 ->  Sort (never executed)
-                                       Sort Key: compress_hyper_2_6_chunk._ts_meta_min_1
-                                       ->  Seq Scan on compress_hyper_2_6_chunk (never executed)
+                     ->  Custom Scan (ColumnarScan) on _hyper_1_3_chunk (never executed)
+                           ->  Sort (never executed)
+                                 Sort Key: compress_hyper_2_6_chunk._ts_meta_min_1
+                                 ->  Seq Scan on compress_hyper_2_6_chunk (never executed)
                      ->  Index Scan Backward using _hyper_1_3_chunk_ht_metrics_partially_compressed_time_idx on _hyper_1_3_chunk (never executed)
 
 -- Ordering by time_bucket, but it's not in the SELECT list.
@@ -261,28 +258,25 @@ order by time_bucket('1 minute', time) limit 1;
          Order: time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time")
          ->  Merge Append (actual rows=1.00 loops=1)
                Sort Key: (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-               ->  Result (actual rows=1.00 loops=1)
-                     ->  Custom Scan (ColumnarScan) on _hyper_1_1_chunk (actual rows=1.00 loops=1)
-                           ->  Sort (actual rows=3.00 loops=1)
-                                 Sort Key: compress_hyper_2_4_chunk._ts_meta_min_1
-                                 Sort Method: quicksort 
-                                 ->  Seq Scan on compress_hyper_2_4_chunk (actual rows=3.00 loops=1)
+               ->  Custom Scan (ColumnarScan) on _hyper_1_1_chunk (actual rows=1.00 loops=1)
+                     ->  Sort (actual rows=3.00 loops=1)
+                           Sort Key: compress_hyper_2_4_chunk._ts_meta_min_1
+                           Sort Method: quicksort 
+                           ->  Seq Scan on compress_hyper_2_4_chunk (actual rows=3.00 loops=1)
                ->  Index Scan Backward using _hyper_1_1_chunk_ht_metrics_partially_compressed_time_idx on _hyper_1_1_chunk (actual rows=1.00 loops=1)
          ->  Merge Append (never executed)
                Sort Key: (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-               ->  Result (never executed)
-                     ->  Custom Scan (ColumnarScan) on _hyper_1_2_chunk (never executed)
-                           ->  Sort (never executed)
-                                 Sort Key: compress_hyper_2_5_chunk._ts_meta_min_1
-                                 ->  Seq Scan on compress_hyper_2_5_chunk (never executed)
+               ->  Custom Scan (ColumnarScan) on _hyper_1_2_chunk (never executed)
+                     ->  Sort (never executed)
+                           Sort Key: compress_hyper_2_5_chunk._ts_meta_min_1
+                           ->  Seq Scan on compress_hyper_2_5_chunk (never executed)
                ->  Index Scan Backward using _hyper_1_2_chunk_ht_metrics_partially_compressed_time_idx on _hyper_1_2_chunk (never executed)
          ->  Merge Append (never executed)
                Sort Key: (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-               ->  Result (never executed)
-                     ->  Custom Scan (ColumnarScan) on _hyper_1_3_chunk (never executed)
-                           ->  Sort (never executed)
-                                 Sort Key: compress_hyper_2_6_chunk._ts_meta_min_1
-                                 ->  Seq Scan on compress_hyper_2_6_chunk (never executed)
+               ->  Custom Scan (ColumnarScan) on _hyper_1_3_chunk (never executed)
+                     ->  Sort (never executed)
+                           Sort Key: compress_hyper_2_6_chunk._ts_meta_min_1
+                           ->  Seq Scan on compress_hyper_2_6_chunk (never executed)
                ->  Index Scan Backward using _hyper_1_3_chunk_ht_metrics_partially_compressed_time_idx on _hyper_1_3_chunk (never executed)
 
 -- Ordering in compressed data order.
@@ -293,32 +287,29 @@ order by device, time_bucket('1 minute', time) limit 1;
  Limit (actual rows=1.00 loops=1)
    ->  Merge Append (actual rows=1.00 loops=1)
          Sort Key: ht_metrics_partially_compressed.device, (time_bucket('@ 1 min'::interval, ht_metrics_partially_compressed."time"))
-         ->  Result (actual rows=1.00 loops=1)
-               ->  Custom Scan (ColumnarScan) on _hyper_1_1_chunk (actual rows=1.00 loops=1)
-                     ->  Sort (actual rows=1.00 loops=1)
-                           Sort Key: compress_hyper_2_4_chunk.device, compress_hyper_2_4_chunk._ts_meta_min_1, compress_hyper_2_4_chunk._ts_meta_max_1
-                           Sort Method: quicksort 
-                           ->  Seq Scan on compress_hyper_2_4_chunk (actual rows=3.00 loops=1)
+         ->  Custom Scan (ColumnarScan) on _hyper_1_1_chunk (actual rows=1.00 loops=1)
+               ->  Sort (actual rows=1.00 loops=1)
+                     Sort Key: compress_hyper_2_4_chunk.device, compress_hyper_2_4_chunk._ts_meta_min_1, compress_hyper_2_4_chunk._ts_meta_max_1
+                     Sort Method: quicksort 
+                     ->  Seq Scan on compress_hyper_2_4_chunk (actual rows=3.00 loops=1)
          ->  Sort (actual rows=1.00 loops=1)
                Sort Key: _hyper_1_1_chunk.device, (time_bucket('@ 1 min'::interval, _hyper_1_1_chunk."time"))
                Sort Method: top-N heapsort 
                ->  Seq Scan on _hyper_1_1_chunk (actual rows=960.00 loops=1)
-         ->  Result (actual rows=1.00 loops=1)
-               ->  Custom Scan (ColumnarScan) on _hyper_1_2_chunk (actual rows=1.00 loops=1)
-                     ->  Sort (actual rows=1.00 loops=1)
-                           Sort Key: compress_hyper_2_5_chunk.device, compress_hyper_2_5_chunk._ts_meta_min_1, compress_hyper_2_5_chunk._ts_meta_max_1
-                           Sort Method: quicksort 
-                           ->  Seq Scan on compress_hyper_2_5_chunk (actual rows=3.00 loops=1)
+         ->  Custom Scan (ColumnarScan) on _hyper_1_2_chunk (actual rows=1.00 loops=1)
+               ->  Sort (actual rows=1.00 loops=1)
+                     Sort Key: compress_hyper_2_5_chunk.device, compress_hyper_2_5_chunk._ts_meta_min_1, compress_hyper_2_5_chunk._ts_meta_max_1
+                     Sort Method: quicksort 
+                     ->  Seq Scan on compress_hyper_2_5_chunk (actual rows=3.00 loops=1)
          ->  Sort (actual rows=1.00 loops=1)
                Sort Key: _hyper_1_2_chunk.device, (time_bucket('@ 1 min'::interval, _hyper_1_2_chunk."time"))
                Sort Method: top-N heapsort 
                ->  Seq Scan on _hyper_1_2_chunk (actual rows=1008.00 loops=1)
-         ->  Result (actual rows=1.00 loops=1)
-               ->  Custom Scan (ColumnarScan) on _hyper_1_3_chunk (actual rows=1.00 loops=1)
-                     ->  Sort (actual rows=1.00 loops=1)
-                           Sort Key: compress_hyper_2_6_chunk.device, compress_hyper_2_6_chunk._ts_meta_min_1, compress_hyper_2_6_chunk._ts_meta_max_1
-                           Sort Method: quicksort 
-                           ->  Seq Scan on compress_hyper_2_6_chunk (actual rows=3.00 loops=1)
+         ->  Custom Scan (ColumnarScan) on _hyper_1_3_chunk (actual rows=1.00 loops=1)
+               ->  Sort (actual rows=1.00 loops=1)
+                     Sort Key: compress_hyper_2_6_chunk.device, compress_hyper_2_6_chunk._ts_meta_min_1, compress_hyper_2_6_chunk._ts_meta_max_1
+                     Sort Method: quicksort 
+                     ->  Seq Scan on compress_hyper_2_6_chunk (actual rows=3.00 loops=1)
          ->  Sort (actual rows=1.00 loops=1)
                Sort Key: _hyper_1_3_chunk.device, (time_bucket('@ 1 min'::interval, _hyper_1_3_chunk."time"))
                Sort Method: top-N heapsort 

tsl/test/expected/compression_sorted_merge.out

@@ -1339,19 +1339,17 @@ set timescaledb.debug_require_batch_sorted_merge to 'force';
 :PREFIX
 SELECT "time","hin"::text,"model"::text,"block"::text,"message_name"::text,"signal_name"::text,"signal_numeric_value","signal_string_value"::text FROM :chunk_table_bugtab ORDER BY "time" DESC;
 --- QUERY PLAN ---
- Result (actual rows=1.00 loops=1)
+ Custom Scan (ColumnarScan) on _timescaledb_internal._hyper_11_23_chunk (actual rows=1.00 loops=1)
    Output: _hyper_11_23_chunk."time", (_hyper_11_23_chunk.hin)::text, (_hyper_11_23_chunk.model)::text, (_hyper_11_23_chunk.block)::text, (_hyper_11_23_chunk.message_name)::text, (_hyper_11_23_chunk.signal_name)::text, _hyper_11_23_chunk.signal_numeric_value, (_hyper_11_23_chunk.signal_string_value)::text
-   ->  Custom Scan (ColumnarScan) on _timescaledb_internal._hyper_11_23_chunk (actual rows=1.00 loops=1)
-         Output: _hyper_11_23_chunk."time", _hyper_11_23_chunk.hin, _hyper_11_23_chunk.model, _hyper_11_23_chunk.block, _hyper_11_23_chunk.message_name, _hyper_11_23_chunk.signal_name, _hyper_11_23_chunk.signal_numeric_value, _hyper_11_23_chunk.signal_string_value
-         Batch Sorted Merge: true
-         Reverse: true
-         Bulk Decompression: false
-         ->  Sort (actual rows=1.00 loops=1)
+   Batch Sorted Merge: true
+   Reverse: true
+   Bulk Decompression: false
+   ->  Sort (actual rows=1.00 loops=1)
+         Output: compress_hyper_12_24_chunk._ts_meta_count, compress_hyper_12_24_chunk.hin, compress_hyper_12_24_chunk.signal_name, compress_hyper_12_24_chunk._ts_meta_min_1, compress_hyper_12_24_chunk._ts_meta_max_1, compress_hyper_12_24_chunk."time", compress_hyper_12_24_chunk.model, compress_hyper_12_24_chunk.block, compress_hyper_12_24_chunk.message_name, compress_hyper_12_24_chunk.signal_numeric_value, compress_hyper_12_24_chunk.signal_string_value
+         Sort Key: compress_hyper_12_24_chunk._ts_meta_max_1 DESC
+         Sort Method: quicksort 
+         ->  Seq Scan on _timescaledb_internal.compress_hyper_12_24_chunk (actual rows=1.00 loops=1)
                Output: compress_hyper_12_24_chunk._ts_meta_count, compress_hyper_12_24_chunk.hin, compress_hyper_12_24_chunk.signal_name, compress_hyper_12_24_chunk._ts_meta_min_1, compress_hyper_12_24_chunk._ts_meta_max_1, compress_hyper_12_24_chunk."time", compress_hyper_12_24_chunk.model, compress_hyper_12_24_chunk.block, compress_hyper_12_24_chunk.message_name, compress_hyper_12_24_chunk.signal_numeric_value, compress_hyper_12_24_chunk.signal_string_value
-               Sort Key: compress_hyper_12_24_chunk._ts_meta_max_1 DESC
-               Sort Method: quicksort 
-               ->  Seq Scan on _timescaledb_internal.compress_hyper_12_24_chunk (actual rows=1.00 loops=1)
-                     Output: compress_hyper_12_24_chunk._ts_meta_count, compress_hyper_12_24_chunk.hin, compress_hyper_12_24_chunk.signal_name, compress_hyper_12_24_chunk._ts_meta_min_1, compress_hyper_12_24_chunk._ts_meta_max_1, compress_hyper_12_24_chunk."time", compress_hyper_12_24_chunk.model, compress_hyper_12_24_chunk.block, compress_hyper_12_24_chunk.message_name, compress_hyper_12_24_chunk.signal_numeric_value, compress_hyper_12_24_chunk.signal_string_value
 
 SELECT "time","hin"::text,"model"::text,"block"::text,"message_name"::text,"signal_name"::text,"signal_numeric_value","signal_string_value"::text FROM :chunk_table_bugtab ORDER BY "time" DESC;
            time           |   hin   |  model   |  block  | message_name | signal_name | signal_numeric_value | signal_string_value