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Fixed LP bug #670380.

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Lifted the limitation that hash join could not be used over 
varchar fields with non-binary collation.
This commit is contained in:
Igor Babaev
2010-12-22 00:37:35 -08:00
parent 4f28dcbe32
commit a095346a9d
9 changed files with 469 additions and 28 deletions
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121
sql/sql_join_cache.cc
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@@ -2520,6 +2520,24 @@ int JOIN_CACHE_HASHED::init()
pack_length+= get_size_of_rec_offset();
pack_length_with_blob_ptrs+= get_size_of_rec_offset();
ref_key_info= join_tab->table->key_info+join_tab->ref.key;
ref_used_key_parts= join_tab->ref.key_parts;
hash_func= &JOIN_CACHE_HASHED::get_hash_idx_simple;
hash_cmp_func= &JOIN_CACHE_HASHED::equal_keys_simple;
KEY_PART_INFO *key_part= ref_key_info->key_part;
KEY_PART_INFO *key_part_end= key_part+ref_used_key_parts;
for ( ; key_part < key_part_end; key_part++)
{
if (!key_part->field->eq_cmp_as_binary())
{
hash_func= &JOIN_CACHE_HASHED::get_hash_idx_complex;
hash_cmp_func= &JOIN_CACHE_HASHED::equal_keys_complex;
break;
}
}
init_hash_table();
rec_fields_offset= get_size_of_rec_offset()+get_size_of_rec_length()+
@@ -2903,7 +2921,7 @@ bool JOIN_CACHE_HASHED::key_search(uchar *key, uint key_len,
uchar **key_ref_ptr)
{
bool is_found= FALSE;
uint idx= get_hash_idx(key, key_length);
uint idx= (this->*hash_func)(key, key_length);
uchar *ref_ptr= hash_table+size_of_key_ofs*idx;
while (!is_null_key_ref(ref_ptr))
{
@@ -2912,7 +2930,7 @@ bool JOIN_CACHE_HASHED::key_search(uchar *key, uint key_len,
next_key= use_emb_key ? get_emb_key(ref_ptr-get_size_of_rec_offset()) :
ref_ptr-key_length;
if (memcmp(next_key, key, key_len) == 0)
if ((this->*hash_cmp_func)(next_key, key, key_len))
{
is_found= TRUE;
break;
@@ -2924,22 +2942,24 @@ bool JOIN_CACHE_HASHED::key_search(uchar *key, uint key_len,
/*
Calclulate hash value for a key in the hash table of the join buffer
Hash function that considers a key in the hash table as byte array
SYNOPSIS
get_hash_idx()
get_hash_idx_simple()
key pointer to the key value
key_len key value length
DESCRIPTION
The function calculates an index of the hash entry in the hash table
of the join buffer for the given key
of the join buffer for the given key. It considers the key just as
a sequence of bytes of the length key_len.
RETURN VALUE
the calculated index of the hash entry for the given key.
the calculated index of the hash entry for the given key
*/
uint JOIN_CACHE_HASHED::get_hash_idx(uchar* key, uint key_len)
inline
uint JOIN_CACHE_HASHED::get_hash_idx_simple(uchar* key, uint key_len)
{
ulong nr= 1;
ulong nr2= 4;
@@ -2954,6 +2974,93 @@ uint JOIN_CACHE_HASHED::get_hash_idx(uchar* key, uint key_len)
}
/*
Hash function that takes into account collations of the components of the key
SYNOPSIS
get_hash_idx_complex()
key pointer to the key value
key_len key value length
DESCRIPTION
The function calculates an index of the hash entry in the hash table
of the join buffer for the given key. It takes into account that the
components of the key may be of a varchar type with different collations.
The function guarantees that the same hash value for any two equal
keys that may differ as byte sequences.
The function takes the info about the components of the key, their
types and used collations from the class member ref_key_info containing
a pointer to the descriptor of the index that can be used for the join
operation.
RETURN VALUE
the calculated index of the hash entry for the given key
*/
inline
uint JOIN_CACHE_HASHED::get_hash_idx_complex(uchar *key, uint key_len)
{
return
(uint) (key_hashnr(ref_key_info, ref_used_key_parts, key) % hash_entries);
}
/*
Compare two key entries in the hash table as sequence of bytes
SYNOPSIS
equal_keys_simple()
key1 pointer to the first key entry
key2 pointer to the second key entry
key_len the length of the key values
DESCRIPTION
The function compares two key entries in the hash table key1 and key2
as two sequences bytes of the length key_len
RETURN VALUE
TRUE key1 coincides with key2
FALSE otherwise
*/
inline
bool JOIN_CACHE_HASHED::equal_keys_simple(uchar *key1, uchar *key2,
uint key_len)
{
return memcmp(key1, key2, key_len) == 0;
}
/*
Compare two key entries taking into account the used collation
SYNOPSIS
equal_keys_complex()
key1 pointer to the first key entry
key2 pointer to the second key entry
key_len the length of the key values
DESCRIPTION
The function checks whether two key entries in the hash table
key1 and key2 are equal as, possibly, compound keys of a certain
structure whose components may be of a varchar type and may
employ different collations.
The descriptor of the key structure is taken from the class
member ref_key_info.
RETURN VALUE
TRUE key1 is equal tokey2
FALSE otherwise
*/
inline
bool JOIN_CACHE_HASHED::equal_keys_complex(uchar *key1, uchar *key2,
uint key_len)
{
return key_buf_cmp(ref_key_info, ref_used_key_parts, key1, key2) == 0;
}
/*
Clean up the hash table of the join buffer