Move mysql_fetch_fields closer to point of use.

Author: sodabrew

ext/mysql2/result.c

@@ -511,6 +511,7 @@ static VALUE rb_mysql_result_fetch_row(VALUE self, MYSQL_FIELD * fields, const r
 {
   VALUE rowVal;
   MYSQL_ROW row;
+  MYSQL_FIELD * fields;
   unsigned int i = 0;
   unsigned long * fieldLengths;
   void * ptr;
@@ -542,6 +543,9 @@ static VALUE rb_mysql_result_fetch_row(VALUE self, MYSQL_FIELD * fields, const r
     wrapper->fields = rb_ary_new2(wrapper->numberOfFields);
   }
 
+  /* get the MySQL field types to convert to Ruby field types */
+  fields = mysql_fetch_fields(wrapper->result);
+
   for (i = 0; i < wrapper->numberOfFields; i++) {
     VALUE field = rb_mysql_result_fetch_field(self, i, args->symbolizeKeys);
     if (row[i]) {
@@ -774,8 +778,6 @@ static VALUE rb_mysql_result_each_(VALUE self,
     if (!wrapper->streamingComplete) {
       VALUE row;
 
-      fields = mysql_fetch_fields(wrapper->result);
-
       do {
         row = fetch_row_func(self, fields, args);
         if (row != Qnil) {
@@ -808,7 +810,6 @@ static VALUE rb_mysql_result_each_(VALUE self,
     } else {
       unsigned long rowsProcessed = 0;
       rowsProcessed = RARRAY_LEN(wrapper->rows);
-      fields = mysql_fetch_fields(wrapper->result);
 
       for (i = 0; i < wrapper->numberOfRows; i++) {
         VALUE row;