From 48ef701fa9d14504870aefc75f5847efbfc495b4 Mon Sep 17 00:00:00 2001
From: Joshua Lockerman <josh@timescale.com>
Date: Fri, 4 Oct 2019 15:01:20 -0400
Subject: [PATCH] Set toast_tuple_target to 128B when able

We want compressed data to be stored out-of-line whenever possible so
that the headers are colocated and scans on the metadata and segmentbys
are cheap. This commit lowers toast_tuple_target to 128 bytes, so that
more tables will have this occur; using the default size, very often a
non-trivial portion of the data ends up in the main table, and only
very few rows are stored in a page.
---
 tsl/src/compression/create.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tsl/src/compression/create.c b/tsl/src/compression/create.c
index d1b30c9d6..e244470fe 100644
--- a/tsl/src/compression/create.c
+++ b/tsl/src/compression/create.c
@@ -495,6 +495,26 @@ set_statistics_on_compressed_table(Oid compressed_table_id)
 	RelationClose(table_rel);
 }
 
+#if !PG96 && !PG10
+static void
+set_toast_tuple_target_on_compressed(Oid compressed_table_id)
+{
+	DefElem def_elem = {
+		.type = T_DefElem,
+		.defname = "toast_tuple_target",
+		.arg = (Node *) makeInteger(128),
+		.defaction = DEFELEM_SET,
+		.location = -1,
+	};
+	AlterTableCmd cmd = {
+		.type = T_AlterTableCmd,
+		.subtype = AT_SetRelOptions,
+		.def = (Node *) list_make1(&def_elem),
+	};
+	AlterTableInternal(compressed_table_id, list_make1(&cmd), true);
+}
+#endif
+
 static int32
 create_compression_table(Oid owner, CompressColInfo *compress_cols)
 {
@@ -540,6 +560,10 @@ create_compression_table(Oid owner, CompressColInfo *compress_cols)
 
 	set_statistics_on_compressed_table(compress_relid);
 
+#if !PG96 && !PG10
+	set_toast_tuple_target_on_compressed(compress_relid);
+#endif
+
 	create_compressed_table_indexes(compress_relid, compress_cols);
 	return compress_hypertable_id;
 }