/*
*
* PROCESS:
* - if the layout as follows(3 pivots, 4 partitions):
*
* +--------+--------+--------+
* | 15 | 17 | 19 | +∞
* +--------+--------+--------+\
* pidx0 pidx1 pidx2 pidx3
*
*
* - so if spk is 16, pidx = 1, after added(4 pivtos, 5 partitions):
*
* +--------+--------+--------+--------+
* | 15 | [16] | 17 | 19 | +∞
* +--------+--------+--------+--------+\
* pidx0 [pidx1] pidx2 pidx3 pidx4
*
*
* ENTER:
* - parent is already locked(L_WRITE)
* - node a is already locked(L_WRITE)
* - node b is already locked(L_WRITE)
*/
static void _add_pivot_to_parent(struct tree *t,
struct node *parent,
int child_num,
struct node *a,
struct node *b,
struct msg *spk)
{
int i;
int pidx;
struct child_pointer *cptr;
pidx = child_num;
parent->pivots = xrealloc(parent->pivots, parent->n_children * PIVOT_SIZE);
parent->parts = xrealloc(parent->parts, (parent->n_children + 1) * PART_SIZE);
/* slide pivots */
for (i = (parent->n_children - 1); i > pidx; i--)
parent->pivots[i] = parent->pivots[i - 1];
/* slide parts */
for (i = parent->n_children; i > pidx; i--)
parent->parts[i] = parent->parts[i - 1];
/* new part */
msgcpy(&parent->pivots[pidx], spk);
parent->parts[pidx].child_nid = a->nid;
cptr = &parent->parts[pidx].ptr;
cptr->u.nonleaf = create_nonleaf(t->e);
parent->parts[pidx + 1].child_nid = b->nid;
parent->n_children += 1;
node_set_dirty(parent);
status_increment(&t->e->status->tree_add_pivots_nums);
}
/*
* EFFECT:
* - alloc ptrs with nonleaf or leaf
* REQUIRE:
* - node has height
* - node has n_children
*/
void node_ptrs_alloc(struct node *node)
{
int i;
for (i = 0; i < node->n_children; i++) {
struct child_pointer *ptr = &node->parts[i].ptr;
if (node->height > 0)
ptr->u.nonleaf = create_nonleaf();
else
ptr->u.leaf = create_leaf();
}
}
/*
* +-----------------------------------------------+
* | 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;
}
