Simple optimization to avoid a malloc for each query

sql/sql_lex.cc

@@ -178,11 +178,8 @@ void lex_start(THD *thd, uchar *buf,uint length)
   lex->trg_table= NULL;
   lex->proc_list.first= 0;
 
-  extern byte *sp_lex_spfuns_key(const byte *ptr, uint *plen, my_bool first);
-  hash_free(&lex->spfuns);
-  hash_init(&lex->spfuns, system_charset_info, 0, 0, 0,
-	    sp_lex_spfuns_key, 0, 0);
-
+  if (lex->spfuns.records)
+    hash_reset(&lex->spfuns);
 }
 
 void lex_end(LEX *lex)

sql/sql_lex.h

@@ -758,7 +758,8 @@ typedef struct st_lex
 
   st_lex() :result(0)
   {
-    bzero((char *)&spfuns, sizeof(spfuns));
+    extern byte *sp_lex_spfuns_key(const byte *ptr, uint *plen, my_bool first);
+    hash_init(&spfuns, system_charset_info, 0, 0, 0, sp_lex_spfuns_key, 0, 0);
   }
   
   ~st_lex()