Use bulk heap insert API for decompression

This should improve the throughput somewhat.

This commit does several things:

* Simplify loop condition in decompressing the compressed batch by using
  the count metadata column.
* Split out a separate function that decompresses the entire compressed
  batch and saves the decompressed tuples slot into RowDecompressor.
* Use bulk table insert function for inserting the decompressed rows,
  this reduces WAL activity.  If we have indexes on uncompressed chunk,
update them one index for entire batch at a time, to reduce load on
shared buffers cache. Before that we used to update all indexes for one
row, then for another, etc.
* Add a test for memory leaks during (de)compression.
* Update the compression_update_delete test to use INFO messages + a
  debug GUC instead of DEBUG messages which are flaky.

This gives 10%-30% speedup on tsbench for decompress_chunk and various
compressed DML queries. This is very far from the performance we had in
2.10, but still a nice improvement.

src/guc.c

@@ -152,6 +152,7 @@ static const struct config_enum_entry require_vector_qual_options[] = {
 #endif
 
 DebugRequireVectorQual ts_guc_debug_require_vector_qual = RVQ_Allow;
+bool ts_guc_debug_compression_path_info = false;
 
 static bool ts_guc_enable_hypertable_create = true;
 static bool ts_guc_enable_hypertable_compression = true;
@@ -827,6 +828,17 @@ _guc_init(void)
 							 /* assign_hook= */ NULL,
 							 /* show_hook= */ NULL);
 
+	DefineCustomBoolVariable(/* name= */ "timescaledb.debug_compression_path_info",
+							 /* short_desc= */ "show various compression-related debug info",
+							 /* long_desc= */ "this is for debugging purposes",
+							 /* valueAddr= */ &ts_guc_debug_compression_path_info,
+							 /* bootValue= */ false,
+							 /* context= */ PGC_USERSET,
+							 /* flags= */ 0,
+							 /* check_hook= */ NULL,
+							 /* assign_hook= */ NULL,
+							 /* show_hook= */ NULL);
+
 	DefineCustomBoolVariable(/* name= */ "timescaledb.debug_require_batch_sorted_merge",
 							 /* short_desc= */ "require batch sorted merge in DecompressChunk node",
 							 /* long_desc= */ "this is for debugging purposes",

src/guc.h

@@ -124,6 +124,8 @@ typedef enum DebugRequireVectorQual
 
 extern TSDLLEXPORT DebugRequireVectorQual ts_guc_debug_require_vector_qual;
 
+extern TSDLLEXPORT bool ts_guc_debug_compression_path_info;
+
 extern TSDLLEXPORT bool ts_guc_debug_require_batch_sorted_merge;
 
 void _guc_init(void);

tsl/src/compression/api.c

@@ -1484,7 +1484,7 @@ tsl_recompress_chunk_segmentwise(PG_FUNCTION_ARGS)
 							  decompressor.compressed_datums,
 							  decompressor.compressed_is_nulls);
 
-			row_decompressor_decompress_row(&decompressor, segment_tuplesortstate);
+			row_decompressor_decompress_row_to_tuplesort(&decompressor, segment_tuplesortstate);
 
 			simple_table_tuple_delete(compressed_chunk_rel, &(slot->tts_tid), snapshot);
 
@@ -1529,7 +1529,7 @@ tsl_recompress_chunk_segmentwise(PG_FUNCTION_ARGS)
 							  decompressor.compressed_datums,
 							  decompressor.compressed_is_nulls);
 
-			row_decompressor_decompress_row(&decompressor, segment_tuplesortstate);
+			row_decompressor_decompress_row_to_tuplesort(&decompressor, segment_tuplesortstate);
 
 			simple_table_tuple_delete(compressed_chunk_rel, &(slot->tts_tid), snapshot);
 			/* because this is the first tuple of the new segment */