diff --git a/src/backend/access/common/toast_compression.c b/src/backend/access/common/toast_compression.c
index 00af1740cf..d772cc0aaa 100644
--- a/src/backend/access/common/toast_compression.c
+++ b/src/backend/access/common/toast_compression.c
@@ -23,8 +23,15 @@
 #include "fmgr.h"
 #include "utils/builtins.h"
 
-/* Compile-time default */
-char	   *default_toast_compression = DEFAULT_TOAST_COMPRESSION;
+/* GUC */
+int	   default_toast_compression = TOAST_PGLZ_COMPRESSION;
+
+#define NO_LZ4_SUPPORT() \
+	ereport(ERROR, \
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED), \
+			 errmsg("unsupported LZ4 compression method"), \
+			 errdetail("This functionality requires the server to be built with lz4 support."), \
+			 errhint("You need to rebuild PostgreSQL using --with-lz4.")))
 
 /*
  * Compress a varlena using PGLZ.
@@ -271,46 +278,41 @@ toast_get_compression_id(struct varlena *attr)
 }
 
 /*
- * Validate a new value for the default_toast_compression GUC.
+ * CompressionNameToMethod - Get compression method from compression name
+ *
+ * Search in the available built-in methods.  If the compression not found
+ * in the built-in methods then return InvalidCompressionMethod.
  */
-bool
-check_default_toast_compression(char **newval, void **extra, GucSource source)
+char
+CompressionNameToMethod(const char *compression)
 {
-	if (**newval == '\0')
+	if (strcmp(compression, "pglz") == 0)
+		return TOAST_PGLZ_COMPRESSION;
+	else if (strcmp(compression, "lz4") == 0)
 	{
-		GUC_check_errdetail("%s cannot be empty.",
-							"default_toast_compression");
-		return false;
+#ifndef USE_LZ4
+		NO_LZ4_SUPPORT();
+#endif
+		return TOAST_LZ4_COMPRESSION;
 	}
 
-	if (strlen(*newval) >= NAMEDATALEN)
-	{
-		GUC_check_errdetail("%s is too long (maximum %d characters).",
-							"default_toast_compression", NAMEDATALEN - 1);
-		return false;
-	}
+	return InvalidCompressionMethod;
+}
 
-	if (!CompressionMethodIsValid(CompressionNameToMethod(*newval)))
+/*
+ * GetCompressionMethodName - Get compression method name
+ */
+const char *
+GetCompressionMethodName(char method)
+{
+	switch (method)
 	{
-		/*
-		 * When source == PGC_S_TEST, don't throw a hard error for a
-		 * nonexistent compression method, only a NOTICE. See comments in
-		 * guc.h.
-		 */
-		if (source == PGC_S_TEST)
-		{
-			ereport(NOTICE,
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
-					 errmsg("compression method \"%s\" does not exist",
-							*newval)));
-		}
-		else
-		{
-			GUC_check_errdetail("Compression method \"%s\" does not exist.",
-								*newval);
-			return false;
-		}
+		case TOAST_PGLZ_COMPRESSION:
+			return "pglz";
+		case TOAST_LZ4_COMPRESSION:
+			return "lz4";
+		default:
+			elog(ERROR, "invalid compression method %c", method);
+			return NULL;		/* keep compiler quiet */
 	}
-
-	return true;
 }
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 3b36a31a47..a4169a6517 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -509,6 +509,14 @@ static struct config_enum_entry shared_memory_options[] = {
 	{NULL, 0, false}
 };
 
+const struct config_enum_entry default_toast_compression_options[] = {
+	{"pglz", TOAST_PGLZ_COMPRESSION, false},
+#ifdef  USE_LZ4
+	{"lz4", TOAST_LZ4_COMPRESSION, false},
+#endif
+	{NULL, 0, false}
+};
+
 /*
  * Options for enum values stored in other modules
  */
@@ -517,6 +525,7 @@ extern const struct config_enum_entry archive_mode_options[];
 extern const struct config_enum_entry recovery_target_action_options[];
 extern const struct config_enum_entry sync_method_options[];
 extern const struct config_enum_entry dynamic_shared_memory_options[];
+extern const struct config_enum_entry default_toast_compression_options[];
 
 /*
  * GUC option variables that are exported from this module
@@ -3943,17 +3952,6 @@ static struct config_string ConfigureNamesString[] =
 		check_default_table_access_method, NULL, NULL
 	},
 
-	{
-		{"default_toast_compression", PGC_USERSET, CLIENT_CONN_STATEMENT,
-			gettext_noop("Sets the default compression for new columns."),
-			NULL,
-			GUC_IS_NAME
-		},
-		&default_toast_compression,
-		DEFAULT_TOAST_COMPRESSION,
-		check_default_toast_compression, NULL, NULL
-	},
-
 	{
 		{"default_tablespace", PGC_USERSET, CLIENT_CONN_STATEMENT,
 			gettext_noop("Sets the default tablespace to create tables and indexes in."),
@@ -4595,6 +4593,17 @@ static struct config_enum ConfigureNamesEnum[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"default_toast_compression", PGC_USERSET, CLIENT_CONN_STATEMENT,
+			gettext_noop("Sets the default compression for new columns."),
+			NULL,
+			GUC_IS_NAME
+		},
+		&default_toast_compression,
+		TOAST_PGLZ_COMPRESSION,
+		default_toast_compression_options, NULL, NULL
+	},
+
 	{
 		{"default_transaction_isolation", PGC_USERSET, CLIENT_CONN_STATEMENT,
 			gettext_noop("Sets the transaction isolation level of each new transaction."),
diff --git a/src/include/access/toast_compression.h b/src/include/access/toast_compression.h
index 44b73bd57c..6cf439ef1a 100644
--- a/src/include/access/toast_compression.h
+++ b/src/include/access/toast_compression.h
@@ -13,18 +13,20 @@
 #ifndef TOAST_COMPRESSION_H
 #define TOAST_COMPRESSION_H
 
-#include "utils/guc.h"
-
 /* GUCs */
-extern char *default_toast_compression;
-
-/* default compression method if not specified. */
-#define DEFAULT_TOAST_COMPRESSION	"pglz"
+extern int default_toast_compression;
 
 /*
  * Built-in compression method-id.  The toast compression header will store
  * this in the first 2 bits of the raw length.  These built-in compression
  * method-id are directly mapped to the built-in compression methods.
+ *
+ * Don't use these values for anything other than understanding the meaning
+ * of the raw bits from a varlena; in particular, if the goal is to identify
+ * a compression method, use the constants TOAST_PGLZ_COMPRESSION, etc.
+ * below. We might someday support more than 4 compression methods, but
+ * we can never have more than 4 values in this enum, because there are
+ * only 2 bits available in the places where this is used.
  */
 typedef enum ToastCompressionId
 {
@@ -39,60 +41,13 @@ typedef enum ToastCompressionId
  */
 #define TOAST_PGLZ_COMPRESSION			'p'
 #define TOAST_LZ4_COMPRESSION			'l'
+#define InvalidCompressionMethod		'\0'
 
-#define InvalidCompressionMethod	'\0'
-#define CompressionMethodIsValid(cm)  ((bool) ((cm) != InvalidCompressionMethod))
-
-#define NO_LZ4_SUPPORT() \
-	ereport(ERROR, \
-			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED), \
-			 errmsg("unsupported LZ4 compression method"), \
-			 errdetail("This functionality requires the server to be built with lz4 support."), \
-			 errhint("You need to rebuild PostgreSQL using --with-lz4.")))
+#define CompressionMethodIsValid(cm)  ((cm) != InvalidCompressionMethod)
 
 #define IsStorageCompressible(storage) ((storage) != TYPSTORAGE_PLAIN && \
 										(storage) != TYPSTORAGE_EXTERNAL)
 
-/*
- * GetCompressionMethodName - Get compression method name
- */
-static inline const char *
-GetCompressionMethodName(char method)
-{
-	switch (method)
-	{
-		case TOAST_PGLZ_COMPRESSION:
-			return "pglz";
-		case TOAST_LZ4_COMPRESSION:
-			return "lz4";
-		default:
-			elog(ERROR, "invalid compression method %c", method);
-			return NULL;		/* keep compiler quiet */
-	}
-}
-
-/*
- * CompressionNameToMethod - Get compression method from compression name
- *
- * Search in the available built-in methods.  If the compression not found
- * in the built-in methods then return InvalidCompressionMethod.
- */
-static inline char
-CompressionNameToMethod(char *compression)
-{
-	if (strcmp(compression, "pglz") == 0)
-		return TOAST_PGLZ_COMPRESSION;
-	else if (strcmp(compression, "lz4") == 0)
-	{
-#ifndef USE_LZ4
-		NO_LZ4_SUPPORT();
-#endif
-		return TOAST_LZ4_COMPRESSION;
-	}
-
-	return InvalidCompressionMethod;
-}
-
 /*
  * GetDefaultToastCompression -- get the default toast compression method
  *
@@ -101,7 +56,7 @@ CompressionNameToMethod(char *compression)
 static inline char
 GetDefaultToastCompression(void)
 {
-	return CompressionNameToMethod(default_toast_compression);
+	return (char) default_toast_compression;
 }
 
 /* pglz compression/decompression routines */
@@ -115,8 +70,10 @@ extern struct varlena *lz4_compress_datum(const struct varlena *value);
 extern struct varlena *lz4_decompress_datum(const struct varlena *value);
 extern struct varlena *lz4_decompress_datum_slice(const struct varlena *value,
 												  int32 slicelength);
+
+/* other stuff */
 extern ToastCompressionId toast_get_compression_id(struct varlena *attr);
-extern bool check_default_toast_compression(char **newval, void **extra,
-											GucSource source);
+extern char CompressionNameToMethod(const char *compression);
+extern const char *GetCompressionMethodName(char method);
 
 #endif							/* TOAST_COMPRESSION_H */
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index c2f2e0e230..566a1877ea 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -234,10 +234,10 @@ DETAIL:  pglz versus lz4
 -- test default_toast_compression GUC
 SET default_toast_compression = '';
 ERROR:  invalid value for parameter "default_toast_compression": ""
-DETAIL:  default_toast_compression cannot be empty.
+HINT:  Available values: pglz, lz4.
 SET default_toast_compression = 'I do not exist compression';
 ERROR:  invalid value for parameter "default_toast_compression": "I do not exist compression"
-DETAIL:  Compression method "I do not exist compression" does not exist.
+HINT:  Available values: pglz, lz4.
 SET default_toast_compression = 'lz4';
 DROP TABLE cmdata2;
 CREATE TABLE cmdata2 (f1 text);
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 6626f8e927..3990933415 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -227,14 +227,13 @@ DETAIL:  pglz versus lz4
 -- test default_toast_compression GUC
 SET default_toast_compression = '';
 ERROR:  invalid value for parameter "default_toast_compression": ""
-DETAIL:  default_toast_compression cannot be empty.
+HINT:  Available values: pglz.
 SET default_toast_compression = 'I do not exist compression';
 ERROR:  invalid value for parameter "default_toast_compression": "I do not exist compression"
-DETAIL:  Compression method "I do not exist compression" does not exist.
+HINT:  Available values: pglz.
 SET default_toast_compression = 'lz4';
-ERROR:  unsupported LZ4 compression method
-DETAIL:  This functionality requires the server to be built with lz4 support.
-HINT:  You need to rebuild PostgreSQL using --with-lz4.
+ERROR:  invalid value for parameter "default_toast_compression": "lz4"
+HINT:  Available values: pglz.
 DROP TABLE cmdata2;
 CREATE TABLE cmdata2 (f1 text);
 \d+ cmdata2