/*
* EFFECT:
* - split leaf&lmb into two leaves:a & b
* a&b are both the half of the lmb
*
* PROCESS:
* - leaf:
* +-----------------------------------+
* | 0 | 1 | 2 | 3 | 4 | 5 |
* +-----------------------------------+
*
* - split:
* root
* +--------+
* | 2 |
* +--------+
* / \
* +-----------------+ +------------------+
* | 0 | 1 | 2 | | 3 | 4 | 5 |
* +-----------------+ +------------------+
* nodea nodeb
*
* ENTER:
* - leaf is already locked (L_WRITE)
* EXITS:
* - a is locked
* - b is locked
*/
void leaf_split(void *tree,
struct node *node,
struct node **a,
struct node **b,
struct msg **split_key)
{
struct partition *pa;
struct partition *pb;
struct node *leafa;
struct node *leafb;
struct lmb *mb;
struct lmb *mba;
struct lmb *mbb;
struct msg *sp_key = NULL;
struct buftree *t = (struct buftree*)tree;
leafa = node;
pa = &leafa->parts[0];
/* split lmb of leaf to mba & mbb */
mb = pa->msgbuf;
lmb_split(mb, &mba, &mbb, &sp_key);
lmb_free(mb);
/* reset leafa buffer */
pa->msgbuf = mba;
/* new leafb */
NID nid = hdr_next_nid(t->hdr);
leaf_new(t->hdr,
nid,
0,
1,
&leafb);
leaf_msgbuf_init(leafb);
cache_put_and_pin(t->cf, nid, leafb);
pb = &leafb->parts[0];
lmb_free(pb->msgbuf);
pb->msgbuf = mbb;
/* set dirty */
node_set_dirty(leafa);
node_set_dirty(leafb);
*a = leafa;
*b = leafb;
*split_key = sp_key;
}
/*
* EFFECT:
* - split the fissible root
*/
void _root_fissible(struct tree *t, struct node *root)
{
struct node *new_root;
uint32_t new_root_height = 1;
uint32_t new_root_children = 2;
/* alloc a nonleaf node with 2 children */
NID nid = hdr_next_nid(t->hdr);
node_create(nid, new_root_height, new_root_children, t->hdr->version, t->e, &new_root);
cache_put_and_pin(t->cf, nid, new_root);
_root_split(t, new_root, root);
cache_unpin(t->cf, root->cpair, make_cpair_attr(root));
cache_unpin(t->cf, new_root->cpair, make_cpair_attr(new_root));
}
struct tree *tree_open(const char *dbname,
struct env *e,
struct tree_callback *tcb) {
int fd;
int flag;
mode_t mode;
int is_create = 0;
struct tree *t;
struct node *root;
struct cache_file *cf;
t = xcalloc(1, sizeof(*t));
t->e = e;
mode = S_IRWXU | S_IRWXG | S_IRWXO;
flag = O_RDWR | O_BINARY;
if (e->use_directio)
fd = ness_os_open_direct(dbname, flag, mode);
else
fd = ness_os_open(dbname, flag, mode);
if (fd == -1) {
if (e->use_directio)
fd = ness_os_open(dbname, flag | O_CREAT, mode);
else
fd = ness_os_open_direct(dbname, flag | O_CREAT, mode);
if (fd == -1)
goto ERR;
is_create = 1;
}
t->fd = fd;
t->hdr = hdr_new(e);
/* tree header */
if (!is_create) {
tcb->fetch_hdr_cb(fd, t->hdr);
}
/* create cache file */
cf = cache_file_create(e->cache, t->fd, t->hdr, tcb);
t->cf = cf;
/* tree root node */
if (is_create) {
NID nid = hdr_next_nid(t->hdr);
node_create(nid, 0, 1, t->hdr->version, t->e, &root);
cache_put_and_pin(cf, nid, root);
root->isroot = 1;
node_set_dirty(root);
cache_unpin(cf, root->cpair, make_cpair_attr(root));
t->hdr->root_nid = root->nid;
__DEBUG("create new root, NID %"PRIu64, root->nid);
} else {
/* get the root node */
if (cache_get_and_pin(cf, t->hdr->root_nid, (void**)&root, L_READ) != NESS_OK)
__PANIC("get root from cache error [%" PRIu64 "]", t->hdr->root_nid);
root->isroot = 1;
cache_unpin(cf, root->cpair, make_cpair_attr(root));
__DEBUG("fetch root, NID %"PRIu64, root->nid);
}
return t;
ERR:
xfree(t);
return NESS_ERR;
}
/*
* +-----------------------------------------------+
* | 5 | 7 | 9 |
* +-----------------------------------------------+
* |
* +---------------+
* | 60 | 61 | 62 |
* +---------------+
*
* +---------------------------------------------------------------+
* | 5 | 60 | 7 | 9 |
* +---------------------------------------------------------------+
* | |
* +--------+ +---------+
* | 60 | | 61 | 62 |
* +--------+ +---------+
*
*
* ENTER:
* - node is already locked(L_WRITE)
* EXITS:
* - a is locked(L_WRITE)
* - b is locked(L_WRITE)
*/
static void _node_split(struct tree *t,
struct node *node,
struct node **a,
struct node **b,
struct msg **split_key)
{
int i;
int pivots_old;
int pivots_in_a;
int pivots_in_b;
struct node *nodea;
struct node *nodeb;
struct msg *spk;
__DEBUG("nonleaf split begin, NID %"PRIu64""
", nodesz %d"
", nodec %d"
", children %d"
, node->nid
, node_size(node)
, node_count(node)
, node->n_children);
nodea = node;
pivots_old = node->n_children - 1;
nassert(pivots_old > 2);
pivots_in_a = pivots_old / 2;
pivots_in_b = pivots_old - pivots_in_a;
/* node a */
nodea->n_children = pivots_in_a + 1;
/* node b */
NID nid = hdr_next_nid(t->hdr);
node_create_light(nid, node->height > 0 ? 1 : 0, pivots_in_b + 1, t->hdr->version, t->e, &nodeb);
cache_put_and_pin(t->cf, nid, nodeb);
for (i = 0; i < (pivots_in_b); i++)
nodeb->pivots[i] = nodea->pivots[pivots_in_a + i];
for (i = 0; i < (pivots_in_b + 1); i++)
nodeb->parts[i] = nodea->parts[pivots_in_a + i];
/* the rightest partition of nodea */
struct child_pointer *ptr = &nodea->parts[pivots_in_a].ptr;
if (nodea->height > 0)
ptr->u.nonleaf = create_nonleaf(t->e);
else
ptr->u.leaf = create_leaf(t->e);
/* split key */
spk = msgdup(&node->pivots[pivots_in_a - 1]);
node_set_dirty(nodea);
node_set_dirty(nodeb);
__DEBUG("nonleaf split end, nodea NID %"PRIu64""
", nodesz %d"
", nodec %d"
", children %d"
, nodea->nid
, node_size(nodea)
, node_count(nodea)
, nodea->n_children);
__DEBUG("nonleaf split end, nodeb NID %"PRIu64""
", nodesz %d"
", nodec %d"
", children %d"
, nodeb->nid
, node_size(nodeb)
, node_count(nodeb)
, nodeb->n_children);
*a = nodea;
*b = nodeb;
*split_key = spk;
}
/*
* EFFECT:
* - split leaf&lmb into two leaves:a & b
* a&b are both the half of the lmb
*
* PROCESS:
* - leaf:
* +-----------------------------------+
* | 0 | 1 | 2 | 3 | 4 | 5 |
* +-----------------------------------+
*
* - split:
* root
* +--------+
* | 2 |
* +--------+
* / \
* +-----------------+ +------------------+
* | 0 | 1 | 2 | | 3 | 4 | 5 |
* +-----------------+ +------------------+
* nodea nodeb
*
* ENTER:
* - leaf is already locked (L_WRITE)
* EXITS:
* - a is locked
* - b is locked
*/
static void _leaf_and_lmb_split(struct tree *t,
struct node *leaf,
struct node **a,
struct node **b,
struct msg **split_key)
{
struct child_pointer *cptra;
struct child_pointer *cptrb;
struct node *leafa;
struct node *leafb;
struct lmb *mb;
struct lmb *mba;
struct lmb *mbb;
struct msg *sp_key = NULL;
__DEBUG("leaf split begin, NID %"PRIu64""
", nodesz %d"
", nodec %d"
", children %d"
, leaf->nid
, node_size(leaf)
, node_count(leaf)
, leaf->n_children);
leafa = leaf;
cptra = &leafa->parts[0].ptr;
/* split lmb of leaf to mba & mbb */
mb = cptra->u.leaf->buffer;
lmb_split(mb, &mba, &mbb, &sp_key);
lmb_free(mb);
/* reset leafa buffer */
cptra->u.leaf->buffer = mba;
/* new leafb */
NID nid = hdr_next_nid(t->hdr);
node_create(nid, 0, 1, t->hdr->version, t->e, &leafb);
cache_put_and_pin(t->cf, nid, leafb);
cptrb = &leafb->parts[0].ptr;
lmb_free(cptrb->u.leaf->buffer);
cptrb->u.leaf->buffer = mbb;
/* set dirty */
node_set_dirty(leafa);
node_set_dirty(leafb);
__DEBUG("leaf split end, leafa NID %"PRIu64""
", nodesz %d"
", nodec %d"
", children %d"
, leafa->nid
, node_size(leafa)
, node_count(leafa)
, leafa->n_children);
__DEBUG("leaf split end, leafb NID %"PRIu64""
", nodesz %d"
", nodec %d"
", children %d"
, leafb->nid
, node_size(leafb)
, node_count(leafb)
, leafb->n_children);
*a = leafa;
*b = leafb;
*split_key = sp_key;
status_increment(&t->e->status->tree_leaf_split_nums);
}
