mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-01-15 19:42:28 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

MDEV-6089 - MySQL WL#7305 "Improve MDL scalability by using lock-free hash"

Browse source 
Extended lf-hash implementation to accept user defined hash function.
This commit is contained in:
Sergey Vojtovich 2015-02-27 00:01:38 +04:00
parent 9c8165fdb4
commit d9e3a9f20e
2 changed files with 14 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
include/lf.h
View file

@ -143,6 +143,7 @@ struct st_lf_hash {
LF_ALLOCATOR alloc; /* allocator for elements */
my_hash_get_key get_key; /* see HASH */
lf_hash_initializer initializer; /* called when an element is inserted */
my_hash_function hash_function; /* see HASH */
CHARSET_INFO *charset; /* see HASH */
uint key_offset, key_length; /* see HASH */
uint element_size; /* size of memcpy'ed area on insert */

20
mysys/lf_hash.c
View file

@ -307,12 +307,13 @@ static inline const uchar* hash_key(const LF_HASH *hash,
@note, that the hash value is limited to 2^31, because we need one
bit to distinguish between normal and dummy nodes.
*/
static inline uint calc_hash(LF_HASH *hash, const uchar *key, uint keylen)
static inline my_hash_value_type calc_hash(const CHARSET_INFO *cs,
const uchar *key,
size_t keylen)
{
ulong nr1= 1, nr2= 4;
hash->charset->coll->hash_sort(hash->charset, (uchar*) key, keylen,
&nr1, &nr2);
return nr1 & INT_MAX32;
cs->coll->hash_sort(cs, (uchar*) key, keylen, &nr1, &nr2);
return nr1;
}
#define MAX_LOAD 1.0 /* average number of elements in a bucket */
@ -356,6 +357,7 @@ void lf_hash_init(LF_HASH *hash, uint element_size, uint flags,
hash->key_length= key_length;
hash->get_key= get_key;
hash->initializer= default_initializer;
hash->hash_function= calc_hash;
DBUG_ASSERT(get_key ? !key_offset && !key_length : key_length);
}
@ -403,7 +405,7 @@ int lf_hash_insert(LF_HASH *hash, LF_PINS *pins, const void *data)
return -1;
hash->initializer(hash, node + 1, data);
node->key= hash_key(hash, (uchar *)(node+1), &node->keylen);
hashnr= calc_hash(hash, node->key, node->keylen);
hashnr= hash->hash_function(hash->charset, node->key, node->keylen) & INT_MAX32;
bucket= hashnr % hash->size;
el= lf_dynarray_lvalue(&hash->array, bucket);
if (unlikely(!el))
@ -436,7 +438,9 @@ int lf_hash_insert(LF_HASH *hash, LF_PINS *pins, const void *data)
int lf_hash_delete(LF_HASH *hash, LF_PINS *pins, const void *key, uint keylen)
{
LF_SLIST * volatile *el;
uint bucket, hashnr= calc_hash(hash, (uchar *)key, keylen);
uint bucket, hashnr;
hashnr= hash->hash_function(hash->charset, (uchar *)key, keylen) & INT_MAX32;
/* hide OOM errors - if we cannot initalize a bucket, try the previous one */
for (bucket= hashnr % hash->size; ;bucket= my_clear_highest_bit(bucket))
@ -522,7 +526,9 @@ int lf_hash_iterate(LF_HASH *hash, LF_PINS *pins,
void *lf_hash_search(LF_HASH *hash, LF_PINS *pins, const void *key, uint keylen)
{
return lf_hash_search_using_hash_value(hash, pins,
calc_hash(hash, (uchar*) key, keylen),
hash->hash_function(hash->charset,
(uchar*) key,
keylen) & INT_MAX32,
key, keylen);
}