diff --git a/doc/sql.extensions/README.ddl.txt b/doc/sql.extensions/README.ddl.txt
index 1b6d4d605c..82c5408754 100644
--- a/doc/sql.extensions/README.ddl.txt
+++ b/doc/sql.extensions/README.ddl.txt
@@ -475,3 +475,14 @@ isc_dpb_sql_role_name tag with required value into DPB, but CREATE DATABASE stat
 missed ROLE clause before 3.0.
 
 ISQL now also takes into an account global role setting when creating databases.
+
+
+19) Added {PRESERVE | DELETE} FILE clause to DROP SHADOW statement.
+(Alex Peshkov)
+
+In some cases it's desired to keep shadow file after dropping shadow (for example for
+backup purporse). In FB3 appropriate clause is added to DROP SHADOW. Full syntax is:
+
+DROP SHADOW number [{PRESERVE | DELETE} FILE];
+
+Default behavior is to delete file keeping backwards compatibility.
diff --git a/src/dsql/parse.y b/src/dsql/parse.y
index 33794ee555..8910850d0f 100644
--- a/src/dsql/parse.y
+++ b/src/dsql/parse.y
@@ -4074,8 +4074,8 @@ drop_clause
 %type <boolVal> opt_no_file_delete
 opt_no_file_delete
 	: /* nothing */			{ $$ = false; }
-	| NO KW_FILE KW_DELETE	{ $$ = true; }
-	| NO KW_DELETE KW_FILE	{ $$ = true; }
+	| PRESERVE KW_FILE		{ $$ = true; }
+	| KW_DELETE KW_FILE		{ $$ = false; }
 	;
 
 // these are the allowable datatypes