diff --git a/contrib/tsearch2/tsvector.c b/contrib/tsearch2/tsvector.c
index ea50421eb73..5670c0cf5fc 100644
--- a/contrib/tsearch2/tsvector.c
+++ b/contrib/tsearch2/tsvector.c
@@ -451,6 +451,8 @@ tsvector_in(PG_FUNCTION_ARGS)
 
 	if (len > 0)
 		len = uniqueentry(arr, len, tmpbuf, &buflen);
+	else
+		buflen=0;
 	totallen = CALCDATASIZE(len, buflen);
 	in = (tsvector *) palloc(totallen);
 	memset(in, 0, totallen);