diff --git a/pgxn/neon/pagestore_smgr.c b/pgxn/neon/pagestore_smgr.c
index cc1bf384cb..f17bc2aad2 100644
--- a/pgxn/neon/pagestore_smgr.c
+++ b/pgxn/neon/pagestore_smgr.c
@@ -748,11 +748,6 @@ neon_exists(SMgrRelation reln, ForkNumber forkNum)
 			neon_log(ERROR, "unknown relpersistence '%c'", reln->smgr_relpersistence);
 	}
 
-	if (get_cached_relsize(InfoFromSMgrRel(reln), forkNum, &n_blocks))
-	{
-		return true;
-	}
-
 	/*
 	 * \d+ on a view calls smgrexists with 0/0/0 relfilenode. The page server
 	 * will error out if you check that, because the whole dbdir for
@@ -780,6 +775,11 @@ neon_exists(SMgrRelation reln, ForkNumber forkNum)
 		return communicator_new_rel_exists(InfoFromSMgrRel(reln), forkNum);
 	else
 	{
+		if (get_cached_relsize(InfoFromSMgrRel(reln), forkNum, &n_blocks))
+		{
+			return true;
+		}
+
 		neon_get_request_lsns(InfoFromSMgrRel(reln), forkNum,
 							  REL_METADATA_PSEUDO_BLOCKNO, &request_lsns, 1);
 
@@ -2216,8 +2216,12 @@ neon_end_unlogged_build(SMgrRelation reln)
 				 RelFileInfoFmt(InfoFromNInfoB(rinfob)),
 				 forknum);
 
-			forget_cached_relsize(InfoFromNInfoB(rinfob), forknum);
-			lfc_invalidate(InfoFromNInfoB(rinfob), forknum, nblocks);
+			// FIXME: also do this with the new communicator
+			if (!neon_enable_new_communicator)
+			{
+				forget_cached_relsize(InfoFromNInfoB(rinfob), forknum);
+				lfc_invalidate(InfoFromNInfoB(rinfob), forknum, nblocks);
+			}
 
 			mdclose(reln, forknum);
 #ifndef DEBUG_COMPARE_LOCAL
diff --git a/pgxn/neon/relsize_cache.c b/pgxn/neon/relsize_cache.c
index 60ca1675d9..4ea303f996 100644
--- a/pgxn/neon/relsize_cache.c
+++ b/pgxn/neon/relsize_cache.c
@@ -10,6 +10,7 @@
  */
 #include "postgres.h"
 
+#include "neon.h"
 #include "neon_pgversioncompat.h"
 
 #include "pagestore_client.h"
@@ -99,6 +100,8 @@ get_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum, BlockNumber *size)
 {
 	bool		found = false;
 
+	Assert(!neon_enable_new_communicator);
+
 	if (relsize_hash_size > 0)
 	{
 		RelTag		tag;
@@ -130,6 +133,8 @@ get_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum, BlockNumber *size)
 void
 set_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum, BlockNumber size)
 {
+	Assert(!neon_enable_new_communicator);
+
 	if (relsize_hash_size > 0)
 	{
 		RelTag		tag;
@@ -178,6 +183,8 @@ set_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum, BlockNumber size)
 void
 update_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum, BlockNumber size)
 {
+	Assert(!neon_enable_new_communicator);
+
 	if (relsize_hash_size > 0)
 	{
 		RelTag		tag;
@@ -212,6 +219,8 @@ update_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum, BlockNumber size)
 void
 forget_cached_relsize(NRelFileInfo rinfo, ForkNumber forknum)
 {
+	Assert(!neon_enable_new_communicator);
+
 	if (relsize_hash_size > 0)
 	{
 		RelTag		tag;