WL#5137, Remove hash calculation from LOCK_open in open_table

include/hash.h

@@ -30,6 +30,7 @@ extern "C" {
 /* flags for hash_init */
 #define HASH_UNIQUE     1       /* hash_insert fails on duplicate key */
 
+typedef uint my_hash_value_type;
 typedef uchar *(*my_hash_get_key)(const uchar *,size_t*,my_bool);
 typedef void (*my_hash_free_key)(void *);
 
@@ -60,8 +61,18 @@ void my_hash_free(HASH *tree);
 void my_hash_reset(HASH *hash);
 uchar *my_hash_element(HASH *hash, ulong idx);
 uchar *my_hash_search(const HASH *info, const uchar *key, size_t length);
+uchar *my_hash_search_using_hash_value(const HASH *info,
+                                       my_hash_value_type hash_value,
+                                       const uchar *key, size_t length);
+my_hash_value_type my_calc_hash(const HASH *info,
+                                const uchar *key, size_t length);
 uchar *my_hash_first(const HASH *info, const uchar *key, size_t length,
                      HASH_SEARCH_STATE *state);
+uchar *my_hash_first_from_hash_value(const HASH *info,
+                                     my_hash_value_type hash_value,
+                                     const uchar *key,
+                                     size_t length,
+                                     HASH_SEARCH_STATE *state);
 uchar *my_hash_next(const HASH *info, const uchar *key, size_t length,
                     HASH_SEARCH_STATE *state);
 my_bool my_hash_insert(HASH *info, const uchar *data);

mysys/hash.c

@@ -33,16 +33,18 @@ typedef struct st_hash_info {
   uchar *data;					/* data for current entry */
 } HASH_LINK;
 
-static uint my_hash_mask(size_t hashnr, size_t buffmax, size_t maxlength);
+static uint my_hash_mask(my_hash_value_type hashnr,
+                         size_t buffmax, size_t maxlength);
 static void movelink(HASH_LINK *array,uint pos,uint next_link,uint newlink);
 static int hashcmp(const HASH *hash, HASH_LINK *pos, const uchar *key,
                    size_t length);
 
-static uint calc_hash(const HASH *hash, const uchar *key, size_t length)
+static my_hash_value_type calc_hash(const HASH *hash,
+                                    const uchar *key, size_t length)
 {
   ulong nr1=1, nr2=4;
   hash->charset->coll->hash_sort(hash->charset,(uchar*) key,length,&nr1,&nr2);
-  return nr1;
+  return (my_hash_value_type)nr1;
 }
 
 /**
@@ -179,7 +181,8 @@ my_hash_key(const HASH *hash, const uchar *record, size_t *length,
 
 	/* Calculate pos according to keys */
 
-static uint my_hash_mask(size_t hashnr, size_t buffmax, size_t maxlength)
+static uint my_hash_mask(my_hash_value_type hashnr, size_t buffmax,
+                         size_t maxlength)
 {
   if ((hashnr & (buffmax-1)) < maxlength) return (hashnr & (buffmax-1));
   return (hashnr & ((buffmax >> 1) -1));
@@ -200,7 +203,7 @@ static
 #if !defined(__USLC__) && !defined(__sgi)
 inline
 #endif
-unsigned int rec_hashnr(HASH *hash,const uchar *record)
+my_hash_value_type rec_hashnr(HASH *hash,const uchar *record)
 {
   size_t length;
   uchar *key= (uchar*) my_hash_key(hash, record, &length, 0);
@@ -214,6 +217,21 @@ uchar* my_hash_search(const HASH *hash, const uchar *key, size_t length)
   return my_hash_first(hash, key, length, &state);
 }
 
+uchar* my_hash_search_using_hash_value(const HASH *hash, 
+                                       my_hash_value_type hash_value,
+                                       const uchar *key,
+                                       size_t length)
+{
+  HASH_SEARCH_STATE state;
+  return my_hash_first_from_hash_value(hash, hash_value,
+                                       key, length, &state);
+}
+
+my_hash_value_type my_calc_hash(const HASH *hash,
+                                const uchar *key, size_t length)
+{
+  return calc_hash(hash, key, length ? length : hash->key_length);
+}
 /*
   Search after a record based on a key
 
@@ -223,15 +241,26 @@ uchar* my_hash_search(const HASH *hash, const uchar *key, size_t length)
 
 uchar* my_hash_first(const HASH *hash, const uchar *key, size_t length,
                      HASH_SEARCH_STATE *current_record)
+{
+  return my_hash_first_from_hash_value(hash,
+                 calc_hash(hash, key, length ? length : hash->key_length),
+                 key, length, current_record);
+}
+                    
+uchar* my_hash_first_from_hash_value(const HASH *hash,
+                                     my_hash_value_type hash_value,
+                                     const uchar *key,
+                                     size_t length,
+                                     HASH_SEARCH_STATE *current_record)
 {
   HASH_LINK *pos;
   uint flag,idx;
-  DBUG_ENTER("my_hash_first");
+  DBUG_ENTER("my_hash_first_from_hash_value");
 
   flag=1;
   if (hash->records)
   {
-    idx= my_hash_mask(calc_hash(hash, key, length ? length : hash->key_length),
+    idx= my_hash_mask(hash_value,
                       hash->blength, hash->records);
     do
     {
@@ -331,7 +360,8 @@ static int hashcmp(const HASH *hash, HASH_LINK *pos, const uchar *key,
 my_bool my_hash_insert(HASH *info, const uchar *record)
 {
   int flag;
-  size_t idx,halfbuff,hash_nr,first_index;
+  size_t idx,halfbuff,first_index;
+  my_hash_value_type hash_nr;
   uchar *UNINIT_VAR(ptr_to_rec),*UNINIT_VAR(ptr_to_rec2);
   HASH_LINK *data,*empty,*UNINIT_VAR(gpos),*UNINIT_VAR(gpos2),*pos;
 
@@ -467,7 +497,8 @@ my_bool my_hash_insert(HASH *info, const uchar *record)
 
 my_bool my_hash_delete(HASH *hash, uchar *record)
 {
-  uint blength,pos2,pos_hashnr,lastpos_hashnr,idx,empty_index;
+  uint blength,pos2,idx,empty_index;
+  my_hash_value_type pos_hashnr, lastpos_hashnr;
   HASH_LINK *data,*lastpos,*gpos,*pos,*pos3,*empty;
   DBUG_ENTER("my_hash_delete");
   if (!hash->records)

sql/sql_base.cc

@@ -2529,6 +2529,7 @@ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
   char	key[MAX_DBKEY_LENGTH];
   uint	key_length;
   char	*alias= table_list->alias;
+  my_hash_value_type hash_value;
   HASH_SEARCH_STATE state;
   DBUG_ENTER("open_table");
 
@@ -2718,6 +2719,7 @@ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
     on disk.
   */
 
+  hash_value= my_calc_hash(&open_cache, (uchar*) key, key_length);
   VOID(pthread_mutex_lock(&LOCK_open));
 
   /*
@@ -2760,7 +2762,10 @@ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
     an implicit "pending locks queue" - see
     wait_for_locked_table_names for details.
   */
-  for (table= (TABLE*) my_hash_first(&open_cache, (uchar*) key, key_length,
+  for (table= (TABLE*) my_hash_first_from_hash_value(&open_cache,
+                                                     hash_value,
+                                                     (uchar*) key,
+                                                     key_length,
                                                      &state);
        table && table->in_use ;
        table= (TABLE*) my_hash_next(&open_cache, (uchar*) key, key_length,