diff --git a/src/test/isolation/specscanner.l b/src/test/isolation/specscanner.l
index 481b32d1d77..f97f4027f2f 100644
--- a/src/test/isolation/specscanner.l
+++ b/src/test/isolation/specscanner.l
@@ -12,8 +12,10 @@
 
 static int	yyline = 1;			/* line number for error reporting */
 
-static char litbuf[1024];
-static int litbufpos = 0;
+#define LITBUF_INIT	1024		/* initial size of litbuf */
+static char *litbuf = NULL;
+static size_t litbufsize = 0;
+static size_t litbufpos = 0;
 
 static void addlitchar(char c);
 
@@ -41,6 +43,11 @@ comment			("#"{non_newline}*)
 
 %%
 
+%{
+	litbuf = pg_malloc(LITBUF_INIT);
+	litbufsize = LITBUF_INIT;
+%}
+
 permutation		{ return PERMUTATION; }
 session			{ return SESSION; }
 setup			{ return SETUP; }
@@ -100,10 +107,12 @@ teardown		{ return TEARDOWN; }
 static void
 addlitchar(char c)
 {
-	if (litbufpos >= sizeof(litbuf) - 1)
+	/* We must always leave room to add a trailing \0 */
+	if (litbufpos >= litbufsize - 1)
 	{
-		fprintf(stderr, "SQL step too long\n");
-		exit(1);
+		/* Double the size of litbuf if it gets full */
+		litbufsize += litbufsize;
+		litbuf = pg_realloc(litbuf, litbufsize);
 	}
 	litbuf[litbufpos++] = c;
 }