Don't detoast compressed data on Bump memory context

PG17 introduced a new Bump allocator for per-tuple memory
contexts. Bump doesn't support pfree(), which caused an error when
detoasting compressed data on the per-tuple memory context since the
detoasting needs to scan some catalog tables.

Make sure Hypercore TAM always detoasts on a temporary memory context
to fix this issue. Also add a test that triggers the failure when the
fix is not present.

tsl/src/hypercore/arrow_array.c

@@ -356,6 +356,13 @@ verify_offsets(const ArrowArray *array)
 ArrowArray *
 arrow_from_compressed(Datum compressed, Oid typid, MemoryContext dest_mcxt, MemoryContext tmp_mcxt)
 {
+	/*
+	 * Need to detoast on our temporary memory context because
+	 * CurrentMemoryContext can be a per-tuple memory context which uses Bump
+	 * allocator on PG17. The Bump allocator doesn't support pfree(), which is
+	 * needed by detoasting since it does some catalog scans.
+	 */
+	MemoryContext oldcxt = MemoryContextSwitchTo(tmp_mcxt);
 	const CompressedDataHeader *header = (CompressedDataHeader *) PG_DETOAST_DATUM(compressed);
 	DecompressAllFunction decompress_all =
 		arrow_get_decompress_all(header->compression_algorithm, typid);
@@ -364,7 +371,6 @@ arrow_from_compressed(Datum compressed, Oid typid, MemoryContext dest_mcxt, Memo
 				 format_type_be(typid),
 				 NameStr(*compression_get_algorithm_name(header->compression_algorithm)));
 
-	MemoryContext oldcxt = MemoryContextSwitchTo(tmp_mcxt);
 	ArrowArray *array = decompress_all(PointerGetDatum(header), typid, dest_mcxt);
 
 	Assert(verify_offsets(array));

tsl/test/expected/hypercore_scans.out

@@ -511,3 +511,26 @@ select time, device+device as device_x2 from :chunk limit 1;
  Wed Jun 01 00:55:00 2022 PDT |         2
 (1 row)
 
+-- Test sort using Bump memory context on PG17. This didn't use to
+-- work on PG17 because it introduced a Bump memory context for
+-- per-tuple processing on which compressed data was detoasted. This
+-- doesn't work because Bump doesn't support pfree(), which is needed
+-- by detoasting.
+--
+-- Need to convert all chunks to Hypercore TAM.
+select compress_chunk(ch, hypercore_use_access_method=>true) from show_chunks('readings') ch;
+             compress_chunk             
+----------------------------------------
+ _timescaledb_internal._hyper_1_1_chunk
+ _timescaledb_internal._hyper_1_2_chunk
+ _timescaledb_internal._hyper_1_3_chunk
+ _timescaledb_internal._hyper_1_4_chunk
+ _timescaledb_internal._hyper_1_5_chunk
+ _timescaledb_internal._hyper_1_6_chunk
+(6 rows)
+
+-- Just test that this query doesn't fail with an error about Bump
+-- allocator not supporting pfree. Redirect output to a temporary
+-- table.
+create temp table test_bump as
+select * from readings order by time, device;

tsl/test/sql/hypercore_scans.sql

@@ -186,3 +186,17 @@ explain
 select time, device+device as device_x2 from :chunk limit 1;
 select time, device+device as device_x2 from :chunk limit 1;
 
+-- Test sort using Bump memory context on PG17. This didn't use to
+-- work on PG17 because it introduced a Bump memory context for
+-- per-tuple processing on which compressed data was detoasted. This
+-- doesn't work because Bump doesn't support pfree(), which is needed
+-- by detoasting.
+--
+-- Need to convert all chunks to Hypercore TAM.
+select compress_chunk(ch, hypercore_use_access_method=>true) from show_chunks('readings') ch;
+
+-- Just test that this query doesn't fail with an error about Bump
+-- allocator not supporting pfree. Redirect output to a temporary
+-- table.
+create temp table test_bump as
+select * from readings order by time, device;