v10-0006-PoC-DSA-support-for-radix-tree.patch

application/octet-stream

Filename: v10-0006-PoC-DSA-support-for-radix-tree.patch
Type: application/octet-stream
Part: 4
Message: Re: [PoC] Improve dead tuple storage for lazy vacuum

Patch

Format: format-patch
Series: patch v10-0006
Subject: PoC: DSA support for radix tree.
File+
contrib/bench_radix_tree/bench_radix_tree--1.0.sql 2 0
contrib/bench_radix_tree/bench_radix_tree.c 9 3
src/backend/lib/radixtree.c 366 117
src/backend/utils/mmgr/dsa.c 12 0
src/include/lib/radixtree.h 7 1
src/include/utils/dsa.h 1 0
src/test/modules/test_radixtree/expected/test_radixtree.out 17 0
src/test/modules/test_radixtree/test_radixtree.c 68 32
From b85513ab0f8654df36aa913f4b29b626e652943f Mon Sep 17 00:00:00 2001
From: Masahiko Sawada <sawada.mshk@gmail.com>
Date: Thu, 27 Oct 2022 14:02:00 +0900
Subject: [PATCH v10 6/7] PoC: DSA support for radix tree.

---
 .../bench_radix_tree--1.0.sql                 |   2 +
 contrib/bench_radix_tree/bench_radix_tree.c   |  12 +-
 src/backend/lib/radixtree.c                   | 483 +++++++++++++-----
 src/backend/utils/mmgr/dsa.c                  |  12 +
 src/include/lib/radixtree.h                   |   8 +-
 src/include/utils/dsa.h                       |   1 +
 .../expected/test_radixtree.out               |  17 +
 .../modules/test_radixtree/test_radixtree.c   | 100 ++--
 8 files changed, 482 insertions(+), 153 deletions(-)

diff --git a/contrib/bench_radix_tree/bench_radix_tree--1.0.sql b/contrib/bench_radix_tree/bench_radix_tree--1.0.sql
index e0205b364e..b5f731f329 100644
--- a/contrib/bench_radix_tree/bench_radix_tree--1.0.sql
+++ b/contrib/bench_radix_tree/bench_radix_tree--1.0.sql
@@ -7,6 +7,7 @@ create function bench_shuffle_search(
 minblk int4,
 maxblk int4,
 random_block bool DEFAULT false,
+shared bool DEFAULT false,
 OUT nkeys int8,
 OUT rt_mem_allocated int8,
 OUT array_mem_allocated int8,
@@ -23,6 +24,7 @@ create function bench_seq_search(
 minblk int4,
 maxblk int4,
 random_block bool DEFAULT false,
+shared bool DEFAULT false,
 OUT nkeys int8,
 OUT rt_mem_allocated int8,
 OUT array_mem_allocated int8,
diff --git a/contrib/bench_radix_tree/bench_radix_tree.c b/contrib/bench_radix_tree/bench_radix_tree.c
index 70ca989118..225a1b3bb1 100644
--- a/contrib/bench_radix_tree/bench_radix_tree.c
+++ b/contrib/bench_radix_tree/bench_radix_tree.c
@@ -15,6 +15,7 @@
 #include "lib/radixtree.h"
 #include <math.h>
 #include "miscadmin.h"
+#include "storage/lwlock.h"
 #include "utils/timestamp.h"
 
 PG_MODULE_MAGIC;
@@ -150,7 +151,9 @@ bench_search(FunctionCallInfo fcinfo, bool shuffle)
 	BlockNumber minblk = PG_GETARG_INT32(0);
 	BlockNumber maxblk = PG_GETARG_INT32(1);
 	bool		random_block = PG_GETARG_BOOL(2);
+	bool		shared = PG_GETARG_BOOL(3);
 	radix_tree *rt = NULL;
+	dsa_area   *dsa = NULL;
 	uint64		ntids;
 	uint64		key;
 	uint64		last_key = PG_UINT64_MAX;
@@ -172,8 +175,11 @@ bench_search(FunctionCallInfo fcinfo, bool shuffle)
 
 	tids = generate_tids(minblk, maxblk, TIDS_PER_BLOCK_FOR_LOAD, &ntids, random_block);
 
+	if (shared)
+		dsa = dsa_create(LWLockNewTrancheId());
+
 	/* measure the load time of the radix tree */
-	rt = rt_create(CurrentMemoryContext);
+	rt = rt_create(CurrentMemoryContext, dsa);
 	start_time = GetCurrentTimestamp();
 	for (int i = 0; i < ntids; i++)
 	{
@@ -324,7 +330,7 @@ bench_load_random_int(PG_FUNCTION_ARGS)
 		elog(ERROR, "return type must be a row type");
 
 	pg_prng_seed(&state, 0);
-	rt = rt_create(CurrentMemoryContext);
+	rt = rt_create(CurrentMemoryContext, NULL);
 
 	start_time = GetCurrentTimestamp();
 	for (uint64 i = 0; i < cnt; i++)
@@ -450,7 +456,7 @@ bench_fixed_height_search(PG_FUNCTION_ARGS)
 	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
 		elog(ERROR, "return type must be a row type");
 
-	rt = rt_create(CurrentMemoryContext);
+	rt = rt_create(CurrentMemoryContext, NULL);
 
 	start_time = GetCurrentTimestamp();
 
diff --git a/src/backend/lib/radixtree.c b/src/backend/lib/radixtree.c
index 08d580a899..1f2bb95e24 100644
--- a/src/backend/lib/radixtree.c
+++ b/src/backend/lib/radixtree.c
@@ -22,6 +22,15 @@
  * choose it to avoid an additional pointer traversal.  It is the reason this code
  * currently does not support variable-length keys.
  *
+ * If DSA space is specified when rt_create(), the radix tree is created in the
+ * DSA space so that multiple processes can access to it simultaneously. The process
+ * who created the shared radix tree need to tell both DSA area specified when
+ * calling to rt_create() and dsa_pointer of the radix tree, fetched by
+ * rt_get_dsa_pointer(), other processes so that they can attach by rt_attach().
+ *
+ * XXX: shared radix tree is still PoC state as it doesn't have any locking support.
+ * Also, it supports only single-process iteration.
+ *
  * XXX: Most functions in this file have two variants for inner nodes and leaf
  * nodes, therefore there are duplication codes. While this sometimes makes the
  * code maintenance tricky, this reduces branch prediction misses when judging
@@ -34,6 +43,9 @@
  *
  * rt_create		- Create a new, empty radix tree
  * rt_free			- Free the radix tree
+ * rt_attach		- Attach to the radix tree
+ * rt_detach		- Detach from the radix tree
+ * rt_get_handle	- Return the handle of the radix tree
  * rt_search		- Search a key-value pair
  * rt_set			- Set a key-value pair
  * rt_delete		- Delete a key-value pair
@@ -64,6 +76,7 @@
 #include "miscadmin.h"
 #include "port/pg_bitutils.h"
 #include "port/pg_lfind.h"
+#include "utils/dsa.h"
 #include "utils/memutils.h"
 
 /* The number of bits encoded in one tree level */
@@ -384,6 +397,11 @@ static rt_node_kind_info_elem rt_node_kind_info[RT_NODE_KIND_COUNT] = {
  * construct the key whenever updating the node iteration information, e.g., when
  * advancing the current index within the node or when moving to the next node
  * at the same level.
+ *
+ * XXX: Currently we allow only one process to do iteration. Therefore, rt_node_iter
+ * has the local pointers to nodes, rather than rt_node_ptr.
+ * We need either a safeguard to disallow other processes to begin the iteration
+ * while one process is doing or to allow multiple processes to do the iteration.
  */
 typedef struct rt_node_iter
 {
@@ -403,23 +421,43 @@ struct rt_iter
 	uint64		key;
 };
 
-/* A radix tree with nodes */
-struct radix_tree
+/* A magic value used to identify our radix tree */
+#define RADIXTREE_MAGIC 0x54A48167
+
+/* Control information for an radix tree */
+typedef struct radix_tree_control
 {
-	MemoryContext context;
+	rt_handle	handle;
+	uint32		magic;
 
+	/* Root node */
 	rt_pointer	root;
-	uint64		max_val;
-	uint64		num_keys;
 
-	MemoryContextData *inner_slabs[RT_NODE_KIND_COUNT];
-	MemoryContextData *leaf_slabs[RT_NODE_KIND_COUNT];
+	pg_atomic_uint64 max_val;
+	pg_atomic_uint64 num_keys;
 
 	/* statistics */
 #ifdef RT_DEBUG
 	int32		cnt[RT_NODE_KIND_COUNT];
 #endif
+} radix_tree_control;
+
+/* A radix tree with nodes */
+struct radix_tree
+{
+	MemoryContext context;
+
+	/* control object in either backend-local memory or DSA */
+	radix_tree_control *ctl;
+
+	/* used only when the radix tree is shared */
+	dsa_area   *area;
+
+	/* used only when the radix tree is private */
+	MemoryContextData *inner_slabs[RT_NODE_KIND_COUNT];
+	MemoryContextData *leaf_slabs[RT_NODE_KIND_COUNT];
 };
+#define RadixTreeIsShared(rt) ((rt)->area != NULL)
 
 static void rt_new_root(radix_tree *tree, uint64 key);
 static rt_node_ptr rt_alloc_node(radix_tree *tree, int kind, uint8 shift, uint8 chunk,
@@ -446,24 +484,31 @@ static void rt_verify_node(rt_node_ptr node);
 
 /* Decode and encode function of rt_pointer */
 static inline rt_node *
-rt_pointer_decode(rt_pointer encoded)
+rt_pointer_decode(radix_tree *tree, rt_pointer encoded)
 {
-	return (rt_node *) RTPointerUnTagKind(encoded);
+	encoded = RTPointerUnTagKind(encoded);
+
+	if (RadixTreeIsShared(tree))
+		return (rt_node *) dsa_get_address(tree->area, encoded);
+	else
+		return (rt_node *) encoded;
 }
 
 static inline rt_pointer
-rt_pointer_encode(rt_node *decoded, uint8 kind)
+rt_pointer_encode(rt_pointer decoded, uint8 kind)
 {
+	Assert((decoded & RT_POINTER_KIND_MASK) == 0);
+
 	return (rt_pointer) RTPointerTagKind(decoded, kind);
 }
 
 /* Return a rt_pointer created from the given encoded pointer */
 static inline rt_node_ptr
-rt_node_ptr_encoded(rt_pointer encoded)
+rt_node_ptr_encoded(radix_tree *tree, rt_pointer encoded)
 {
 	return (rt_node_ptr) {
 		.encoded = encoded,
-			.decoded = rt_pointer_decode(encoded)
+			.decoded = rt_pointer_decode(tree, encoded)
 			};
 }
 
@@ -908,8 +953,8 @@ rt_new_root(radix_tree *tree, uint64 key)
 	rt_node_ptr	node;
 
 	node = rt_alloc_node(tree, RT_NODE_KIND_4, shift, 0, shift > 0);
-	tree->max_val = shift_get_max_val(shift);
-	tree->root = node.encoded;
+	pg_atomic_write_u64(&tree->ctl->max_val, shift_get_max_val(shift));
+	tree->ctl->root = node.encoded;
 }
 
 /*
@@ -918,16 +963,35 @@ rt_new_root(radix_tree *tree, uint64 key)
 static rt_node_ptr
 rt_alloc_node(radix_tree *tree, int kind, uint8 shift, uint8 chunk, bool inner)
 {
-	rt_node_ptr	newnode;
+	rt_node_ptr newnode;
+
+	if (tree->area != NULL)
+	{
+		dsa_pointer dp;
+
+		if (inner)
+			dp = dsa_allocate0(tree->area, rt_node_kind_info[kind].inner_size);
+		else
+			dp = dsa_allocate0(tree->area, rt_node_kind_info[kind].leaf_size);
 
-	if (inner)
-		newnode.decoded = (rt_node *) MemoryContextAllocZero(tree->inner_slabs[kind],
-															 rt_node_kind_info[kind].inner_size);
+		newnode.encoded = rt_pointer_encode((rt_pointer) dp, kind);
+		newnode.decoded = (rt_node *) dsa_get_address(tree->area, dp);
+	}
 	else
-		newnode.decoded = (rt_node *) MemoryContextAllocZero(tree->leaf_slabs[kind],
-															 rt_node_kind_info[kind].leaf_size);
+	{
+		rt_node *new;
+
+		if (inner)
+			new = (rt_node *) MemoryContextAllocZero(tree->inner_slabs[kind],
+													 rt_node_kind_info[kind].inner_size);
+		else
+			new = (rt_node *) MemoryContextAllocZero(tree->leaf_slabs[kind],
+													 rt_node_kind_info[kind].leaf_size);
+
+		newnode.encoded = rt_pointer_encode((rt_pointer) new, kind);
+		newnode.decoded = new;
+	}
 
-	newnode.encoded = rt_pointer_encode(newnode.decoded, kind);
 	NODE_SHIFT(newnode) = shift;
 	NODE_CHUNK(newnode) = chunk;
 
@@ -941,7 +1005,7 @@ rt_alloc_node(radix_tree *tree, int kind, uint8 shift, uint8 chunk, bool inner)
 
 #ifdef RT_DEBUG
 	/* update the statistics */
-	tree->cnt[kind]++;
+	tree->ctl->cnt[kind]++;
 #endif
 
 	return newnode;
@@ -968,16 +1032,19 @@ static void
 rt_free_node(radix_tree *tree, rt_node_ptr node)
 {
 	/* If we're deleting the root node, make the tree empty */
-	if (tree->root == node.encoded)
-		tree->root = InvalidRTPointer;
+	if (tree->ctl->root == node.encoded)
+		tree->ctl->root = InvalidRTPointer;
 
 #ifdef RT_DEBUG
 	/* update the statistics */
-	tree->cnt[NODE_KIND(node)]--;
-	Assert(tree->cnt[NODE_KIND(node)] >= 0);
+	tree->ctl->cnt[NODE_KIND(node)]--;
+	Assert(tree->ctl->cnt[NODE_KIND(node)] >= 0);
 #endif
 
-	pfree(node.decoded);
+	if (RadixTreeIsShared(tree))
+		dsa_free(tree->area, (dsa_pointer) RTPointerUnTagKind(node.encoded));
+	else
+		pfree(node.decoded);
 }
 
 /*
@@ -993,7 +1060,7 @@ rt_replace_node(radix_tree *tree, rt_node_ptr parent, rt_node_ptr old_child,
 	if (rt_node_ptr_eq(&parent, &old_child))
 	{
 		/* Replace the root node with the new large node */
-		tree->root = new_child.encoded;
+		tree->ctl->root = new_child.encoded;
 	}
 	else
 	{
@@ -1015,7 +1082,7 @@ static void
 rt_extend(radix_tree *tree, uint64 key)
 {
 	int			target_shift;
-	rt_node		*root = rt_pointer_decode(tree->root);
+	rt_node		*root = rt_pointer_decode(tree, tree->ctl->root);
 	int			shift = root->shift + RT_NODE_SPAN;
 
 	target_shift = key_get_shift(key);
@@ -1031,15 +1098,15 @@ rt_extend(radix_tree *tree, uint64 key)
 
 		n4->base.n.count = 1;
 		n4->base.chunks[0] = 0;
-		n4->children[0] = tree->root;
+		n4->children[0] = tree->ctl->root;
 
 		root->chunk = 0;
-		tree->root = node.encoded;
+		tree->ctl->root = node.encoded;
 
 		shift += RT_NODE_SPAN;
 	}
 
-	tree->max_val = shift_get_max_val(target_shift);
+	pg_atomic_write_u64(&tree->ctl->max_val, shift_get_max_val(target_shift));
 }
 
 /*
@@ -1068,7 +1135,7 @@ rt_set_extend(radix_tree *tree, uint64 key, uint64 value, rt_node_ptr parent,
 	}
 
 	rt_node_insert_leaf(tree, parent, node, key, value);
-	tree->num_keys++;
+	pg_atomic_add_fetch_u64(&tree->ctl->num_keys, 1);
 }
 
 /*
@@ -1079,8 +1146,7 @@ rt_set_extend(radix_tree *tree, uint64 key, uint64 value, rt_node_ptr parent,
  * pointer is set to child_p.
  */
 static inline bool
-rt_node_search_inner(rt_node_ptr node, uint64 key, rt_action action,
-					 rt_pointer *child_p)
+rt_node_search_inner(rt_node_ptr node, uint64 key, rt_action action, rt_pointer *child_p)
 {
 	uint8		chunk = RT_GET_KEY_CHUNK(key, NODE_SHIFT(node));
 	bool		found = false;
@@ -1115,6 +1181,7 @@ rt_node_search_inner(rt_node_ptr node, uint64 key, rt_action action,
 					break;
 
 				found = true;
+
 				if (action == RT_ACTION_FIND)
 					child = n32->children[idx];
 				else			/* RT_ACTION_DELETE */
@@ -1604,33 +1671,50 @@ rt_node_insert_leaf(radix_tree *tree, rt_node_ptr parent, rt_node_ptr node,
  * Create the radix tree in the given memory context and return it.
  */
 radix_tree *
-rt_create(MemoryContext ctx)
+rt_create(MemoryContext ctx, dsa_area *area)
 {
 	radix_tree *tree;
 	MemoryContext old_ctx;
 
 	old_ctx = MemoryContextSwitchTo(ctx);
 
-	tree = palloc(sizeof(radix_tree));
+	tree = (radix_tree *) palloc0(sizeof(radix_tree));
 	tree->context = ctx;
-	tree->root = InvalidRTPointer;
-	tree->max_val = 0;
-	tree->num_keys = 0;
+
+	if (area != NULL)
+	{
+		dsa_pointer dp;
+
+		tree->area = area;
+		dp = dsa_allocate0(area, sizeof(radix_tree_control));
+		tree->ctl = (radix_tree_control *) dsa_get_address(area, dp);
+		tree->ctl->handle = (rt_handle) dp;
+	}
+	else
+	{
+		tree->ctl = (radix_tree_control *) palloc0(sizeof(radix_tree_control));
+		tree->ctl->handle = InvalidDsaPointer;
+	}
+
+	tree->ctl->magic = RADIXTREE_MAGIC;
+	tree->ctl->root = InvalidRTPointer;
+	pg_atomic_init_u64(&tree->ctl->max_val, 0);
+	pg_atomic_init_u64(&tree->ctl->num_keys, 0);
 
 	/* Create the slab allocator for each size class */
-	for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+	if (area == NULL)
 	{
-		tree->inner_slabs[i] = SlabContextCreate(ctx,
-												 rt_node_kind_info[i].name,
-												 rt_node_kind_info[i].inner_blocksize,
-												 rt_node_kind_info[i].inner_size);
-		tree->leaf_slabs[i] = SlabContextCreate(ctx,
-												rt_node_kind_info[i].name,
-												rt_node_kind_info[i].leaf_blocksize,
-												rt_node_kind_info[i].leaf_size);
-#ifdef RT_DEBUG
-		tree->cnt[i] = 0;
-#endif
+		for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+		{
+			tree->inner_slabs[i] = SlabContextCreate(ctx,
+													 rt_node_kind_info[i].name,
+													 rt_node_kind_info[i].inner_blocksize,
+													 rt_node_kind_info[i].inner_size);
+			tree->leaf_slabs[i] = SlabContextCreate(ctx,
+													rt_node_kind_info[i].name,
+													rt_node_kind_info[i].leaf_blocksize,
+													rt_node_kind_info[i].leaf_size);
+		}
 	}
 
 	MemoryContextSwitchTo(old_ctx);
@@ -1638,16 +1722,160 @@ rt_create(MemoryContext ctx)
 	return tree;
 }
 
+/*
+ * Get a handle that can be used by other processes to attach to this radix
+ * tree.
+ */
+dsa_pointer
+rt_get_handle(radix_tree *tree)
+{
+	Assert(RadixTreeIsShared(tree));
+	Assert(tree->ctl->magic == RADIXTREE_MAGIC);
+
+	return tree->ctl->handle;
+}
+
+/*
+ * Attach to an existing radix tree using a handle. The returned object is
+ * allocated in backend-local memory using the CurrentMemoryContext.
+ */
+radix_tree *
+rt_attach(dsa_area *area, rt_handle handle)
+{
+	radix_tree *tree;
+	dsa_pointer	control;
+
+	/* Allocate the backend-local object representing the radix tree */
+	tree = (radix_tree *) palloc0(sizeof(radix_tree));
+
+	/* Find the control object in shard memory */
+	control = handle;
+
+	/* Set up the local radix tree */
+	tree->area = area;
+	tree->ctl = (radix_tree_control *) dsa_get_address(area, control);
+	Assert(tree->ctl->magic == RADIXTREE_MAGIC);
+
+	return tree;
+}
+
+/*
+ * Detach from a radix tree. This frees backend-local resources associated
+ * with the radix tree, but the radix tree will continue to exist until
+ * it is explicitly freed.
+ */
+void
+rt_detach(radix_tree *tree)
+{
+	Assert(RadixTreeIsShared(tree));
+	Assert(tree->ctl->magic == RADIXTREE_MAGIC);
+
+	pfree(tree);
+}
+
+/*
+ * Recursively free all nodes allocated to the dsa area.
+ */
+static void
+rt_free_recurse(radix_tree *tree, rt_pointer ptr)
+{
+	rt_node_ptr	node = rt_node_ptr_encoded(tree, ptr);
+
+	Assert(RadixTreeIsShared(tree));
+
+	/* The leaf node doesn't have child pointers, so free it */
+	if (NODE_IS_LEAF(node))
+	{
+		dsa_free(tree->area, RTPointerUnTagKind(node.encoded));
+		return;
+	}
+
+	switch (NODE_KIND(node))
+	{
+		case RT_NODE_KIND_4:
+			{
+				rt_node_inner_4 *n4 = (rt_node_inner_4 *) node.decoded;
+
+				/* Free all children recursively */
+				for (int i = 0; i < NODE_COUNT(node); i++)
+					rt_free_recurse(tree, n4->children[i]);
+
+				break;
+			}
+		case RT_NODE_KIND_32:
+			{
+				rt_node_inner_32 *n32 = (rt_node_inner_32 *) node.decoded;
+
+				/* Free all children recursively */
+				for (int i = 0; i < NODE_COUNT(node); i++)
+					rt_free_recurse(tree, n32->children[i]);
+
+				break;
+			}
+		case RT_NODE_KIND_128:
+			{
+				rt_node_inner_128 *n128 = (rt_node_inner_128 *) node.decoded;
+
+				/* Free all children recursively */
+				for (int i = 0; i < RT_NODE_MAX_SLOTS; i++)
+				{
+					if (!node_128_is_chunk_used((rt_node_base_128 *) n128, i))
+						continue;
+
+					rt_free_recurse(tree, node_inner_128_get_child(n128, i));
+				}
+				break;
+			}
+		case RT_NODE_KIND_256:
+			{
+				rt_node_inner_256 *n256 = (rt_node_inner_256 *) node.decoded;
+
+				/* Free all children recursively */
+				for (int i = 0; i < RT_NODE_MAX_SLOTS; i++)
+				{
+					if (!node_inner_256_is_chunk_used(n256, i))
+						continue;
+
+					rt_free_recurse(tree, node_inner_256_get_child(n256, i));
+				}
+				break;
+			}
+	}
+
+	/* Free the inner node itself */
+	dsa_free(tree->area, RTPointerUnTagKind(node.encoded));
+}
+
 /*
  * Free the given radix tree.
  */
 void
 rt_free(radix_tree *tree)
 {
-	for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+	Assert(!RadixTreeIsShared(tree) || tree->ctl->magic == RADIXTREE_MAGIC);
+
+	if (RadixTreeIsShared(tree))
 	{
-		MemoryContextDelete(tree->inner_slabs[i]);
-		MemoryContextDelete(tree->leaf_slabs[i]);
+		/* Free all memory used for radix tree nodes */
+		if (RTPointerIsValid(tree->ctl->root))
+			rt_free_recurse(tree, tree->ctl->root);
+
+		/*
+		 * Vandalize the control block to help catch programming error where
+		 * other backends access the memory formerly occupied by this radix tree.
+		 */
+		tree->ctl->magic = 0;
+		dsa_free(tree->area, tree->ctl->handle);
+	}
+	else
+	{
+		/* Free all memory used for radix tree nodes */
+		for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+		{
+			MemoryContextDelete(tree->inner_slabs[i]);
+			MemoryContextDelete(tree->leaf_slabs[i]);
+		}
+		pfree(tree->ctl);
 	}
 
 	pfree(tree);
@@ -1665,16 +1893,18 @@ rt_set(radix_tree *tree, uint64 key, uint64 value)
 	rt_node_ptr	node;
 	rt_node_ptr parent;
 
+	Assert(!RadixTreeIsShared(tree) || tree->ctl->magic == RADIXTREE_MAGIC);
+
 	/* Empty tree, create the root */
-	if (!RTPointerIsValid(tree->root))
+	if (!RTPointerIsValid(tree->ctl->root))
 		rt_new_root(tree, key);
 
 	/* Extend the tree if necessary */
-	if (key > tree->max_val)
+	if (key > pg_atomic_read_u64(&tree->ctl->max_val))
 		rt_extend(tree, key);
 
 	/* Descend the tree until a leaf node */
-	node = parent = rt_node_ptr_encoded(tree->root);
+	node = parent = rt_node_ptr_encoded(tree, tree->ctl->root);
 	shift = NODE_SHIFT(node);
 	while (shift >= 0)
 	{
@@ -1690,7 +1920,7 @@ rt_set(radix_tree *tree, uint64 key, uint64 value)
 		}
 
 		parent = node;
-		node = rt_node_ptr_encoded(child);
+		node = rt_node_ptr_encoded(tree, child);
 		shift -= RT_NODE_SPAN;
 	}
 
@@ -1698,7 +1928,7 @@ rt_set(radix_tree *tree, uint64 key, uint64 value)
 
 	/* Update the statistics */
 	if (!updated)
-		tree->num_keys++;
+		pg_atomic_add_fetch_u64(&tree->ctl->num_keys, 1);
 
 	return updated;
 }
@@ -1714,12 +1944,14 @@ rt_search(radix_tree *tree, uint64 key, uint64 *value_p)
 	rt_node_ptr    node;
 	int			shift;
 
+	Assert(!RadixTreeIsShared(tree) || tree->ctl->magic == RADIXTREE_MAGIC);
 	Assert(value_p != NULL);
 
-	if (!RTPointerIsValid(tree->root) || key > tree->max_val)
+	if (!RTPointerIsValid(tree->ctl->root) ||
+		key > pg_atomic_read_u64(&tree->ctl->max_val))
 		return false;
 
-	node = rt_node_ptr_encoded(tree->root);
+	node = rt_node_ptr_encoded(tree, tree->ctl->root);
 	shift = NODE_SHIFT(node);
 
 	/* Descend the tree until a leaf node */
@@ -1733,7 +1965,7 @@ rt_search(radix_tree *tree, uint64 key, uint64 *value_p)
 		if (!rt_node_search_inner(node, key, RT_ACTION_FIND, &child))
 			return false;
 
-		node = rt_node_ptr_encoded(child);
+		node = rt_node_ptr_encoded(tree, child);
 		shift -= RT_NODE_SPAN;
 	}
 
@@ -1753,14 +1985,17 @@ rt_delete(radix_tree *tree, uint64 key)
 	int			level;
 	bool		deleted;
 
-	if (!tree->root || key > tree->max_val)
+	Assert(!RadixTreeIsShared(tree) || tree->ctl->magic == RADIXTREE_MAGIC);
+
+	if (!RTPointerIsValid(tree->ctl->root) ||
+		key > pg_atomic_read_u64(&tree->ctl->max_val))
 		return false;
 
 	/*
 	 * Descend the tree to search the key while building a stack of nodes we
 	 * visited.
 	 */
-	node = rt_node_ptr_encoded(tree->root);
+	node = rt_node_ptr_encoded(tree, tree->ctl->root);
 	shift = NODE_SHIFT(node);
 	level = -1;
 	while (shift > 0)
@@ -1773,7 +2008,7 @@ rt_delete(radix_tree *tree, uint64 key)
 		if (!rt_node_search_inner(node, key, RT_ACTION_FIND, &child))
 			return false;
 
-		node = rt_node_ptr_encoded(child);
+		node = rt_node_ptr_encoded(tree, child);
 		shift -= RT_NODE_SPAN;
 	}
 
@@ -1788,7 +2023,7 @@ rt_delete(radix_tree *tree, uint64 key)
 	}
 
 	/* Found the key to delete. Update the statistics */
-	tree->num_keys--;
+	pg_atomic_sub_fetch_u64(&tree->ctl->num_keys, 1);
 
 	/*
 	 * Return if the leaf node still has keys and we don't need to delete the
@@ -1822,8 +2057,8 @@ rt_delete(radix_tree *tree, uint64 key)
 	 */
 	if (level == 0)
 	{
-		tree->root = InvalidRTPointer;
-		tree->max_val = 0;
+		tree->ctl->root = InvalidRTPointer;
+		pg_atomic_write_u64(&tree->ctl->max_val, 0);
 	}
 
 	return true;
@@ -1838,6 +2073,8 @@ rt_begin_iterate(radix_tree *tree)
 	rt_iter    *iter;
 	int			top_level;
 
+	Assert(!RadixTreeIsShared(tree) || tree->ctl->magic == RADIXTREE_MAGIC);
+
 	old_ctx = MemoryContextSwitchTo(tree->context);
 
 	iter = (rt_iter *) palloc0(sizeof(rt_iter));
@@ -1847,7 +2084,7 @@ rt_begin_iterate(radix_tree *tree)
 	if (!RTPointerIsValid(iter->tree))
 		return iter;
 
-	root = rt_node_ptr_encoded(iter->tree->root);
+	root = rt_node_ptr_encoded(tree, iter->tree->ctl->root);
 	top_level = NODE_SHIFT(root) / RT_NODE_SPAN;
 	iter->stack_len = top_level;
 
@@ -1898,6 +2135,8 @@ rt_update_iter_stack(rt_iter *iter, rt_node_ptr from_node, int from)
 bool
 rt_iterate_next(rt_iter *iter, uint64 *key_p, uint64 *value_p)
 {
+	Assert(!RadixTreeIsShared(iter->tree) || iter->tree->ctl->magic == RADIXTREE_MAGIC);
+
 	/* Empty tree */
 	if (!iter->tree)
 		return false;
@@ -2043,7 +2282,7 @@ rt_node_inner_iterate_next(rt_iter *iter, rt_node_iter *node_iter, rt_node_ptr *
 	if (found)
 	{
 		rt_iter_update_key(iter, key_chunk, NODE_SHIFT(node));
-		*child_p = rt_node_ptr_encoded(child);
+		*child_p = rt_node_ptr_encoded(iter->tree, child);
 	}
 
 	return found;
@@ -2146,7 +2385,7 @@ rt_node_leaf_iterate_next(rt_iter *iter, rt_node_iter *node_iter, uint64 *value_
 uint64
 rt_num_entries(radix_tree *tree)
 {
-	return tree->num_keys;
+	return pg_atomic_read_u64(&tree->ctl->num_keys);
 }
 
 /*
@@ -2155,12 +2394,19 @@ rt_num_entries(radix_tree *tree)
 uint64
 rt_memory_usage(radix_tree *tree)
 {
-	Size		total = sizeof(radix_tree);
+	Size		total = sizeof(radix_tree) + sizeof(radix_tree_control);
 
-	for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+	Assert(!RadixTreeIsShared(tree) || tree->ctl->magic == RADIXTREE_MAGIC);
+
+	if (RadixTreeIsShared(tree))
+		total = dsa_get_total_size(tree->area);
+	else
 	{
-		total += MemoryContextMemAllocated(tree->inner_slabs[i], true);
-		total += MemoryContextMemAllocated(tree->leaf_slabs[i], true);
+		for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+		{
+			total += MemoryContextMemAllocated(tree->inner_slabs[i], true);
+			total += MemoryContextMemAllocated(tree->leaf_slabs[i], true);
+		}
 	}
 
 	return total;
@@ -2244,19 +2490,19 @@ rt_verify_node(rt_node_ptr node)
 void
 rt_stats(radix_tree *tree)
 {
-	rt_node_ptr	root = rt_node_ptr_encoded(tree->root);
+	rt_node_ptr	root = rt_node_ptr_encoded(tree, tree->ctl->root);
 
 	ereport(LOG, (errmsg("num_keys = %lu, height = %u, n4 = %u, n32 = %u, n128 = %u, n256 = %u",
-						 tree->num_keys,
+						 pg_atomic_read_u64(&tree->ctl->num_keys),
 						 NODE_SHIFT(root) / RT_NODE_SPAN,
-						 tree->cnt[0],
-						 tree->cnt[1],
-						 tree->cnt[2],
-						 tree->cnt[3])));
+						 tree->ctl->cnt[0],
+						 tree->ctl->cnt[1],
+						 tree->ctl->cnt[2],
+						 tree->ctl->cnt[3])));
 }
 
 static void
-rt_dump_node(rt_node_ptr node, int level, bool recurse)
+rt_dump_node(radix_tree *tree, rt_node_ptr node, int level, bool recurse)
 {
 	rt_node		*n = node.decoded;
 	char		space[128] = {0};
@@ -2292,7 +2538,7 @@ rt_dump_node(rt_node_ptr node, int level, bool recurse)
 								space, n4->base.chunks[i]);
 
 						if (recurse)
-							rt_dump_node(rt_node_ptr_encoded(n4->children[i]),
+							rt_dump_node(tree, rt_node_ptr_encoded(tree, n4->children[i]),
 										 level + 1, recurse);
 						else
 							fprintf(stderr, "\n");
@@ -2320,7 +2566,7 @@ rt_dump_node(rt_node_ptr node, int level, bool recurse)
 
 						if (recurse)
 						{
-							rt_dump_node(rt_node_ptr_encoded(n32->children[i]),
+							rt_dump_node(tree, rt_node_ptr_encoded(tree, n32->children[i]),
 										 level + 1, recurse);
 						}
 						else
@@ -2373,7 +2619,9 @@ rt_dump_node(rt_node_ptr node, int level, bool recurse)
 								space, i);
 
 						if (recurse)
-							rt_dump_node(rt_node_ptr_encoded(node_inner_128_get_child(n128, i)),
+							rt_dump_node(tree,
+										 rt_node_ptr_encoded(tree,
+															 node_inner_128_get_child(n128, i)),
 										 level + 1, recurse);
 						else
 							fprintf(stderr, "\n");
@@ -2406,7 +2654,9 @@ rt_dump_node(rt_node_ptr node, int level, bool recurse)
 								space, i);
 
 						if (recurse)
-							rt_dump_node(rt_node_ptr_encoded(node_inner_256_get_child(n256, i)),
+							rt_dump_node(tree,
+										 rt_node_ptr_encoded(tree,
+															 node_inner_256_get_child(n256, i)),
 										 level + 1, recurse);
 						else
 							fprintf(stderr, "\n");
@@ -2417,6 +2667,27 @@ rt_dump_node(rt_node_ptr node, int level, bool recurse)
 	}
 }
 
+void
+rt_dump(radix_tree *tree)
+{
+	for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
+		fprintf(stderr, "%s\tinner_size%lu\tinner_blocksize %lu\tleaf_size %lu\tleaf_blocksize %lu\n",
+				rt_node_kind_info[i].name,
+				rt_node_kind_info[i].inner_size,
+				rt_node_kind_info[i].inner_blocksize,
+				rt_node_kind_info[i].leaf_size,
+				rt_node_kind_info[i].leaf_blocksize);
+	fprintf(stderr, "max_val = %lu\n", pg_atomic_read_u64(&tree->ctl->max_val));
+
+	if (!tree->ctl->root)
+	{
+		fprintf(stderr, "empty tree\n");
+		return;
+	}
+
+	rt_dump_node(tree, rt_node_ptr_encoded(tree, tree->ctl->root), 0, true);
+}
+
 void
 rt_dump_search(radix_tree *tree, uint64 key)
 {
@@ -2425,28 +2696,30 @@ rt_dump_search(radix_tree *tree, uint64 key)
 	int			level = 0;
 
 	elog(NOTICE, "-----------------------------------------------------------");
-	elog(NOTICE, "max_val = %lu (0x%lX)", tree->max_val, tree->max_val);
+	elog(NOTICE, "max_val = %lu (0x%lX)",
+		 pg_atomic_read_u64(&tree->ctl->max_val),
+		 pg_atomic_read_u64(&tree->ctl->max_val));
 
-	if (!RTPointerIsValid(tree->root))
+	if (!RTPointerIsValid(tree->ctl->root))
 	{
 		elog(NOTICE, "tree is empty");
 		return;
 	}
 
-	if (key > tree->max_val)
+	if (key > pg_atomic_read_u64(&tree->ctl->max_val))
 	{
 		elog(NOTICE, "key %lu (0x%lX) is larger than max val",
 			 key, key);
 		return;
 	}
 
-	node = rt_node_ptr_encoded(tree->root);
+	node = rt_node_ptr_encoded(tree, tree->ctl->root);
 	shift = NODE_SHIFT(node);
 	while (shift >= 0)
 	{
 		rt_pointer   child;
 
-		rt_dump_node(node, level, false);
+		rt_dump_node(tree, node, level, false);
 
 		if (NODE_IS_LEAF(node))
 		{
@@ -2461,33 +2734,9 @@ rt_dump_search(radix_tree *tree, uint64 key)
 		if (!rt_node_search_inner(node, key, RT_ACTION_FIND, &child))
 			break;
 
-		node = rt_node_ptr_encoded(child);
+		node = rt_node_ptr_encoded(tree, child);
 		shift -= RT_NODE_SPAN;
 		level++;
 	}
 }
-
-void
-rt_dump(radix_tree *tree)
-{
-	rt_node_ptr root;
-
-	for (int i = 0; i < RT_NODE_KIND_COUNT; i++)
-		fprintf(stderr, "%s\tinner_size%lu\tinner_blocksize %lu\tleaf_size %lu\tleaf_blocksize %lu\n",
-				rt_node_kind_info[i].name,
-				rt_node_kind_info[i].inner_size,
-				rt_node_kind_info[i].inner_blocksize,
-				rt_node_kind_info[i].leaf_size,
-				rt_node_kind_info[i].leaf_blocksize);
-	fprintf(stderr, "max_val = %lu\n", tree->max_val);
-
-	if (!RTPointerIsValid(tree->root))
-	{
-		fprintf(stderr, "empty tree\n");
-		return;
-	}
-
-	root = rt_node_ptr_encoded(tree->root);
-	rt_dump_node(root, 0, true);
-}
 #endif
diff --git a/src/backend/utils/mmgr/dsa.c b/src/backend/utils/mmgr/dsa.c
index 82376fde2d..ad169882af 100644
--- a/src/backend/utils/mmgr/dsa.c
+++ b/src/backend/utils/mmgr/dsa.c
@@ -1024,6 +1024,18 @@ dsa_set_size_limit(dsa_area *area, size_t limit)
 	LWLockRelease(DSA_AREA_LOCK(area));
 }
 
+size_t
+dsa_get_total_size(dsa_area *area)
+{
+	size_t		size;
+
+	LWLockAcquire(DSA_AREA_LOCK(area), LW_SHARED);
+	size = area->control->total_segment_size;
+	LWLockRelease(DSA_AREA_LOCK(area));
+
+	return size;
+}
+
 /*
  * Aggressively free all spare memory in the hope of returning DSM segments to
  * the operating system.
diff --git a/src/include/lib/radixtree.h b/src/include/lib/radixtree.h
index d5d7668617..68a11df970 100644
--- a/src/include/lib/radixtree.h
+++ b/src/include/lib/radixtree.h
@@ -14,18 +14,24 @@
 #define RADIXTREE_H
 
 #include "postgres.h"
+#include "utils/dsa.h"
 
 #define RT_DEBUG 1
 
 typedef struct radix_tree radix_tree;
 typedef struct rt_iter rt_iter;
+typedef dsa_pointer rt_handle;
 
-extern radix_tree *rt_create(MemoryContext ctx);
+extern radix_tree *rt_create(MemoryContext ctx, dsa_area *dsa);
 extern void rt_free(radix_tree *tree);
 extern bool rt_search(radix_tree *tree, uint64 key, uint64 *val_p);
 extern bool rt_set(radix_tree *tree, uint64 key, uint64 val);
 extern rt_iter *rt_begin_iterate(radix_tree *tree);
 
+extern rt_handle rt_get_handle(radix_tree *tree);
+extern radix_tree *rt_attach(dsa_area *dsa, dsa_pointer dp);
+extern void rt_detach(radix_tree *tree);
+
 extern bool rt_iterate_next(rt_iter *iter, uint64 *key_p, uint64 *value_p);
 extern void rt_end_iterate(rt_iter *iter);
 extern bool rt_delete(radix_tree *tree, uint64 key);
diff --git a/src/include/utils/dsa.h b/src/include/utils/dsa.h
index 405606fe2f..dad06adecc 100644
--- a/src/include/utils/dsa.h
+++ b/src/include/utils/dsa.h
@@ -117,6 +117,7 @@ extern dsa_handle dsa_get_handle(dsa_area *area);
 extern dsa_pointer dsa_allocate_extended(dsa_area *area, size_t size, int flags);
 extern void dsa_free(dsa_area *area, dsa_pointer dp);
 extern void *dsa_get_address(dsa_area *area, dsa_pointer dp);
+extern size_t dsa_get_total_size(dsa_area *area);
 extern void dsa_trim(dsa_area *area);
 extern void dsa_dump(dsa_area *area);
 
diff --git a/src/test/modules/test_radixtree/expected/test_radixtree.out b/src/test/modules/test_radixtree/expected/test_radixtree.out
index cc6970c87c..a0ff1e1c77 100644
--- a/src/test/modules/test_radixtree/expected/test_radixtree.out
+++ b/src/test/modules/test_radixtree/expected/test_radixtree.out
@@ -5,21 +5,38 @@ CREATE EXTENSION test_radixtree;
 --
 SELECT test_radixtree();
 NOTICE:  testing radix tree node types with shift "0"
+NOTICE:  testing radix tree node types with shift "0"
+NOTICE:  testing radix tree node types with shift "8"
 NOTICE:  testing radix tree node types with shift "8"
 NOTICE:  testing radix tree node types with shift "16"
+NOTICE:  testing radix tree node types with shift "16"
 NOTICE:  testing radix tree node types with shift "24"
+NOTICE:  testing radix tree node types with shift "24"
+NOTICE:  testing radix tree node types with shift "32"
 NOTICE:  testing radix tree node types with shift "32"
 NOTICE:  testing radix tree node types with shift "40"
+NOTICE:  testing radix tree node types with shift "40"
+NOTICE:  testing radix tree node types with shift "48"
 NOTICE:  testing radix tree node types with shift "48"
 NOTICE:  testing radix tree node types with shift "56"
+NOTICE:  testing radix tree node types with shift "56"
+NOTICE:  testing radix tree with pattern "all ones"
 NOTICE:  testing radix tree with pattern "all ones"
 NOTICE:  testing radix tree with pattern "alternating bits"
+NOTICE:  testing radix tree with pattern "alternating bits"
+NOTICE:  testing radix tree with pattern "clusters of ten"
 NOTICE:  testing radix tree with pattern "clusters of ten"
 NOTICE:  testing radix tree with pattern "clusters of hundred"
+NOTICE:  testing radix tree with pattern "clusters of hundred"
+NOTICE:  testing radix tree with pattern "one-every-64k"
 NOTICE:  testing radix tree with pattern "one-every-64k"
 NOTICE:  testing radix tree with pattern "sparse"
+NOTICE:  testing radix tree with pattern "sparse"
+NOTICE:  testing radix tree with pattern "single values, distance > 2^32"
 NOTICE:  testing radix tree with pattern "single values, distance > 2^32"
 NOTICE:  testing radix tree with pattern "clusters, distance > 2^32"
+NOTICE:  testing radix tree with pattern "clusters, distance > 2^32"
+NOTICE:  testing radix tree with pattern "clusters, distance > 2^60"
 NOTICE:  testing radix tree with pattern "clusters, distance > 2^60"
  test_radixtree 
 ----------------
diff --git a/src/test/modules/test_radixtree/test_radixtree.c b/src/test/modules/test_radixtree/test_radixtree.c
index cb3596755d..a948cba4ec 100644
--- a/src/test/modules/test_radixtree/test_radixtree.c
+++ b/src/test/modules/test_radixtree/test_radixtree.c
@@ -19,6 +19,7 @@
 #include "nodes/bitmapset.h"
 #include "storage/block.h"
 #include "storage/itemptr.h"
+#include "storage/lwlock.h"
 #include "utils/memutils.h"
 #include "utils/timestamp.h"
 
@@ -111,7 +112,7 @@ test_empty(void)
 	radix_tree *radixtree;
 	uint64		dummy;
 
-	radixtree = rt_create(CurrentMemoryContext);
+	radixtree = rt_create(CurrentMemoryContext, NULL);
 
 	if (rt_search(radixtree, 0, &dummy))
 		elog(ERROR, "rt_search on empty tree returned true");
@@ -217,14 +218,10 @@ test_node_types_delete(radix_tree *radixtree, uint8 shift)
  * level.
  */
 static void
-test_node_types(uint8 shift)
+do_test_node_types(radix_tree *radixtree, uint8 shift)
 {
-	radix_tree *radixtree;
-
 	elog(NOTICE, "testing radix tree node types with shift \"%d\"", shift);
 
-	radixtree = rt_create(CurrentMemoryContext);
-
 	/*
 	 * Insert and search entries for every node type at the 'shift' level,
 	 * then delete all entries to make it empty, and insert and search entries
@@ -233,19 +230,39 @@ test_node_types(uint8 shift)
 	test_node_types_insert(radixtree, shift);
 	test_node_types_delete(radixtree, shift);
 	test_node_types_insert(radixtree, shift);
+}
 
-	rt_free(radixtree);
+static void
+test_node_types(void)
+{
+	int			tranche_id = LWLockNewTrancheId();
+
+	for (int shift = 0; shift <= (64 - 8); shift += 8)
+	{
+		radix_tree *tree;
+		dsa_area   *dsa;
+
+		/* Test the local radix tree */
+		tree = rt_create(CurrentMemoryContext, NULL);
+		do_test_node_types(tree, shift);
+		rt_free(tree);
+
+		/* Test the shared radix tree */
+		dsa = dsa_create(tranche_id);
+		tree = rt_create(CurrentMemoryContext, dsa);
+		do_test_node_types(tree, shift);
+		rt_free(tree);
+		dsa_detach(dsa);
+	}
 }
 
 /*
  * Test with a repeating pattern, defined by the 'spec'.
  */
 static void
-test_pattern(const test_spec * spec)
+do_test_pattern(radix_tree *radixtree, const test_spec * spec)
 {
-	radix_tree *radixtree;
 	rt_iter    *iter;
-	MemoryContext radixtree_ctx;
 	TimestampTz starttime;
 	TimestampTz endtime;
 	uint64		n;
@@ -271,18 +288,6 @@ test_pattern(const test_spec * spec)
 			pattern_values[pattern_num_values++] = i;
 	}
 
-	/*
-	 * Allocate the radix tree.
-	 *
-	 * Allocate it in a separate memory context, so that we can print its
-	 * memory usage easily.
-	 */
-	radixtree_ctx = AllocSetContextCreate(CurrentMemoryContext,
-										  "radixtree test",
-										  ALLOCSET_SMALL_SIZES);
-	MemoryContextSetIdentifier(radixtree_ctx, spec->test_name);
-	radixtree = rt_create(radixtree_ctx);
-
 	/*
 	 * Add values to the set.
 	 */
@@ -336,8 +341,6 @@ test_pattern(const test_spec * spec)
 		mem_usage = rt_memory_usage(radixtree);
 		fprintf(stderr, "rt_memory_usage() reported " UINT64_FORMAT " (%0.2f bytes / integer)\n",
 				mem_usage, (double) mem_usage / spec->num_values);
-
-		MemoryContextStats(radixtree_ctx);
 	}
 
 	/* Check that rt_num_entries works */
@@ -484,21 +487,54 @@ test_pattern(const test_spec * spec)
 	if ((nbefore - ndeleted) != nafter)
 		elog(ERROR, "rt_num_entries returned " UINT64_FORMAT ", expected " UINT64_FORMAT "after " UINT64_FORMAT " deletion",
 			 nafter, (nbefore - ndeleted), ndeleted);
+}
+
+static void
+test_patterns(void)
+{
+	int			tranche_id = LWLockNewTrancheId();
+
+	/* Test different test patterns, with lots of entries */
+	for (int i = 0; i < lengthof(test_specs); i++)
+	{
+		radix_tree *tree;
+		MemoryContext radixtree_ctx;
+		dsa_area   *dsa;
+		const		test_spec *spec = &test_specs[i];
 
-	MemoryContextDelete(radixtree_ctx);
+		/*
+		 * Allocate the radix tree.
+		 *
+		 * Allocate it in a separate memory context, so that we can print its
+		 * memory usage easily.
+		 */
+		radixtree_ctx = AllocSetContextCreate(CurrentMemoryContext,
+											  "radixtree test",
+											  ALLOCSET_SMALL_SIZES);
+		MemoryContextSetIdentifier(radixtree_ctx, spec->test_name);
+
+		/* Test the local radix tree */
+		tree = rt_create(radixtree_ctx, NULL);
+		do_test_pattern(tree, spec);
+		rt_free(tree);
+		MemoryContextReset(radixtree_ctx);
+
+		/* Test the shared radix tree */
+		dsa = dsa_create(tranche_id);
+		tree = rt_create(radixtree_ctx, dsa);
+		do_test_pattern(tree, spec);
+		rt_free(tree);
+		dsa_detach(dsa);
+		MemoryContextDelete(radixtree_ctx);
+	}
 }
 
 Datum
 test_radixtree(PG_FUNCTION_ARGS)
 {
 	test_empty();
-
-	for (int shift = 0; shift <= (64 - 8); shift += 8)
-		test_node_types(shift);
-
-	/* Test different test patterns, with lots of entries */
-	for (int i = 0; i < lengthof(test_specs); i++)
-		test_pattern(&test_specs[i]);
+	test_node_types();
+	test_patterns();
 
 	PG_RETURN_VOID();
 }
-- 
2.31.1