Fix memory allocation for output of hstore type.

Per "maosen.zhang" <maosen.zhang@alibaba-inc.com> report.

diff --git a/contrib/hstore/hstore_io.c b/contrib/hstore/hstore_io.c
index 08fc32e5099b28e3defc7f08def4d86ab911bf40..02eace243d8b39896bca1f3c9b24717a63717a08 100644 (file)
--- a/contrib/hstore/hstore_io.c
+++ b/contrib/hstore/hstore_io.c
@@ -442,7 +442,8 @@ hstore_out(PG_FUNCTION_ARGS)
 {
        HStore     *in = PG_GETARG_HS(0);
        int                     buflen,
-                               i;
+                               i,
+                               nnulls=0;
        char       *out,
                           *ptr;
        char       *base = STRPTR(in);
@@ -456,8 +457,14 @@ hstore_out(PG_FUNCTION_ARGS)
                PG_RETURN_CSTRING(out);
        }
 
-       buflen = (4 /* " */ + 2 /* => */ + 2 /* , */ ) * in->size +
-               2 /* esc */ * (in->len - CALCDATASIZE(in->size, 0));
+       for (i = 0; i < in->size; i++)
+               if (entries[i].valisnull)
+                       nnulls++;
+       buflen = (4 /* " */ + 2 /* => */ ) * ( in->size - nnulls ) +
+                       ( 2 /* " */ + 2 /* => */ + 4 /* NULL */ ) * nnulls  +
+                       2 /* ,  */ * ( in->size - 1 ) +
+                       2 /* esc */ * (VARSIZE(in) - CALCDATASIZE(in->size, 0)) +
+                       1 /* \0 */;
 
        out = ptr = palloc(buflen);
        for (i = 0; i < in->size; i++)