diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index f670e2d4c31..cb7afca9079 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -10020,7 +10020,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         The supported compression methods are <literal>pglz</literal> and
         (if <productname>PostgreSQL</productname> was compiled with
         <option>--with-lz4</option>) <literal>lz4</literal>.
-        The default is <literal>pglz</literal>.
+        The default is <literal>lz4</literal> (if available); otherwise,
+        <literal>pglz</literal>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/common/toast_compression.c b/src/backend/access/common/toast_compression.c
index 4d00537049e..5a5d579494a 100644
--- a/src/backend/access/common/toast_compression.c
+++ b/src/backend/access/common/toast_compression.c
@@ -23,7 +23,7 @@
 #include "varatt.h"
 
 /* GUC */
-int			default_toast_compression = TOAST_PGLZ_COMPRESSION;
+int			default_toast_compression = DEFAULT_TOAST_COMPRESSION;
 
 #define NO_COMPRESSION_SUPPORT(method) \
 	ereport(ERROR, \
diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat
index 9507778415d..5ee84a639d8 100644
--- a/src/backend/utils/misc/guc_parameters.dat
+++ b/src/backend/utils/misc/guc_parameters.dat
@@ -735,7 +735,7 @@
 { name => 'default_toast_compression', type => 'enum', context => 'PGC_USERSET', group => 'CLIENT_CONN_STATEMENT',
   short_desc => 'Sets the default compression method for compressible values.',
   variable => 'default_toast_compression',
-  boot_val => 'TOAST_PGLZ_COMPRESSION',
+  boot_val => 'DEFAULT_TOAST_COMPRESSION',
   options => 'default_toast_compression_options',
 },
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f938cc65a3a..e686d88afc4 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -779,7 +779,7 @@
 #row_security = on
 #default_table_access_method = 'heap'
 #default_tablespace = ''                # a tablespace name, '' uses the default
-#default_toast_compression = 'pglz'     # 'pglz' or 'lz4'
+#default_toast_compression = pglz       # pglz or lz4
 #temp_tablespaces = ''                  # a list of tablespace names, '' uses
                                         # only default tablespace
 #check_function_bodies = on
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 53ec1544ff3..6387c66289e 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -1426,6 +1426,11 @@ setup_config(void)
 									  "0640", false);
 	}
 
+#if USE_LZ4
+	conflines = replace_guc_value(conflines, "default_toast_compression",
+								  "lz4", true);
+#endif
+
 	/*
 	 * Now replace anything that's overridden via -c switches.
 	 */
diff --git a/src/include/access/toast_compression.h b/src/include/access/toast_compression.h
index 5f3ffa9ab2d..3265f10b734 100644
--- a/src/include/access/toast_compression.h
+++ b/src/include/access/toast_compression.h
@@ -52,6 +52,15 @@ typedef enum ToastCompressionId
 
 #define CompressionMethodIsValid(cm)  ((cm) != InvalidCompressionMethod)
 
+/*
+ * Choose an appropriate default toast compression method.  If lz4 is
+ * compiled-in, use it, otherwise use pglz.
+ */
+#ifdef USE_LZ4
+#define DEFAULT_TOAST_COMPRESSION	TOAST_LZ4_COMPRESSION
+#else
+#define DEFAULT_TOAST_COMPRESSION	TOAST_PGLZ_COMPRESSION
+#endif
 
 /* pglz compression/decompression routines */
 extern varlena *pglz_compress_datum(const varlena *value);