rc_t btree_impl::_ux_adopt_foster_core (btree_page_h &parent, btree_page_h &child,
const w_keystr_t &new_child_key)
{
w_assert1 (g_xct()->is_single_log_sys_xct());
w_assert1 (parent.is_fixed());
w_assert1 (parent.latch_mode() == LATCH_EX);
w_assert1 (parent.is_node());
w_assert1 (child.is_fixed());
w_assert1 (child.latch_mode() == LATCH_EX);
w_assert0 (child.get_foster() != 0);
PageID new_child_pid = child.get_foster();
if (smlevel_0::bf->is_swizzled_pointer(new_child_pid)) {
smlevel_0::bf->unswizzle(parent.get_generic_page(),
GeneralRecordIds::FOSTER_CHILD, true, &new_child_pid);
}
w_assert1(!smlevel_0::bf->is_swizzled_pointer(new_child_pid));
lsn_t child_emlsn = child.get_foster_emlsn();
W_DO(log_btree_foster_adopt (parent, child, new_child_pid, child_emlsn, new_child_key));
_ux_adopt_foster_apply_parent (parent, new_child_pid, child_emlsn, new_child_key);
_ux_adopt_foster_apply_child (child);
// Switch parent of newly adopted child
// CS TODO: I'm not sure we can do this because we don't hold a latch on new_child_pid
smlevel_0::bf->switch_parent(new_child_pid, parent.get_generic_page());
w_assert3(parent.is_consistent(true, true));
w_assert3(child.is_consistent(true, true));
return RCOK;
}
rc_t btree_impl::_sx_adopt_foster_all_core (
btree_page_h &parent, bool is_root, bool recursive)
{
// TODO this should use the improved tree-walk-through
// See jira ticket:60 "Tree walk-through without more than 2 pages latched" (originally trac ticket:62)
w_assert1 (xct()->is_sys_xct());
w_assert1 (parent.is_fixed());
w_assert1 (parent.latch_mode() == LATCH_EX);
if (parent.is_node()) {
w_assert1(parent.pid0());
W_DO(_sx_adopt_foster_sweep(parent));
if (recursive) {
// also adopt at all children recursively
for (int i = -1; i < parent.nrecs(); ++i) {
btree_page_h child;
PageID shpid_opaqueptr = i == -1 ? parent.get_foster_opaqueptr() : parent.child_opaqueptr(i);
W_DO(child.fix_nonroot(parent, shpid_opaqueptr, LATCH_EX));
W_DO(_sx_adopt_foster_all_core(child, false, true));
}
}
}
// after all adopts, if this parent is the root and has foster,
// let's grow the tree
if (is_root && parent.get_foster()) {
W_DO(_sx_grow_tree(parent));
W_DO(_sx_adopt_foster_sweep(parent));
}
w_assert3(parent.is_consistent(true, true));
return RCOK;
}
rc_t btree_impl::_ux_assure_fence_low_entry(btree_page_h &leaf)
{
w_assert1(leaf.is_fixed());
w_assert1(leaf.latch_mode() == LATCH_EX);
if (!leaf.is_leaf()) {
// locks are taken only for leaf-page entries. this case isn't an issue
return RCOK;
}
w_keystr_t fence_low;
leaf.copy_fence_low_key(fence_low);
bool needs_to_create = false;
if (leaf.nrecs() == 0) {
if (leaf.compare_with_fence_high(fence_low) == 0) {
// low==high happens only during page split. In that case, no one can have a lock
// in the page being created. No need to assure the record.
return RCOK;
}
needs_to_create = true;
} else {
w_keystr_t first_key;
leaf.get_key(0, first_key);
w_assert1(fence_low.compare(first_key) <= 0); // can't be fence_low>first_key
if (fence_low.compare(first_key) < 0) {
// fence-low doesn't exist as an entry!
needs_to_create = true;
}
}
if (needs_to_create) {
W_DO(_sx_reserve_ghost(leaf, fence_low, 0)); // no data is needed
}
return RCOK;
}
rc_t btree_impl::_ux_norec_alloc_core(btree_page_h &page, PageID &new_page_id) {
// This is called only in REDO-only SSX, so no compensation logging. Just apply.
w_assert1 (xct()->is_single_log_sys_xct());
w_assert1 (page.latch_mode() == LATCH_EX);
W_DO(smlevel_0::vol->alloc_a_page(new_page_id));
btree_page_h new_page;
w_rc_t rc;
rc = new_page.fix_nonroot(page, new_page_id, LATCH_EX, false, true);
if (rc.is_error()) {
// if failed for any reason, we release the allocated page.
W_DO(smlevel_0::vol ->deallocate_page(new_page_id));
return rc;
}
// The new page has an empty key range; parent's high to high.
w_keystr_t fence, chain_high;
page.copy_fence_high_key(fence);
bool was_right_most = (page.get_chain_fence_high_length() == 0);
page.copy_chain_fence_high_key(chain_high);
if (was_right_most) {
// this means there was no chain or the page was the right-most of it.
// (so its high=high of chain)
// upon the first foster split, we start setting the chain-high.
page.copy_fence_high_key(chain_high);
}
#if W_DEBUG_LEVEL >= 3
lsn_t old_lsn = page.get_page_lsn();
#endif //W_DEBUG_LEVEL
W_DO(log_btree_norec_alloc(page, new_page, new_page_id, fence, chain_high));
DBGOUT3(<< "btree_impl::_ux_norec_alloc_core, fence=" << fence << ", old-LSN="
<< old_lsn << ", new-LSN=" << page.get_page_lsn() << ", PID=" << new_page_id);
// initialize as an empty child:
new_page.format_steal(page.get_page_lsn(), new_page_id, page.store(),
page.root(), page.level(), 0, lsn_t::null,
page.get_foster_opaqueptr(), page.get_foster_emlsn(),
fence, fence, chain_high, false);
page.accept_empty_child(page.get_page_lsn(), new_page_id, false /*not from redo*/);
// in this operation, the log contains everything we need to recover without any
// write-order-dependency. So, no registration for WOD.
w_assert3(new_page.is_consistent(true, true));
w_assert1(new_page.is_fixed());
w_assert1(new_page.latch_mode() == LATCH_EX);
w_assert3(page.is_consistent(true, true));
w_assert1(page.is_fixed());
return RCOK;
}
rc_t btree_impl::_sx_split_foster(btree_page_h& page, PageID& new_page_id,
const w_keystr_t& triggering_key)
{
sys_xct_section_t sxs(true);
W_DO(sxs.check_error_on_start());
w_assert1 (page.latch_mode() == LATCH_EX);
// DBG(<< "SPLITTING " << page);
/*
* Step 1: Allocate a new page for the foster child
*/
W_DO(smlevel_0::vol->alloc_a_page(new_page_id));
/*
* Step 2: Create new foster child and move records into it, logging its
* raw contents as a page_img_format operation
*/
btree_page_h new_page;
rc_t rc = new_page.fix_nonroot(page, new_page_id,
LATCH_EX, false, true);
if (rc.is_error()) {
W_DO(smlevel_0::vol ->deallocate_page(new_page_id));
return rc;
}
// assure foster-child page has an entry same as fence-low for locking correctness.
// See jira ticket:84 "Key Range Locking" (originally trac ticket:86).
// CS TODO - why is this required
// There may be a bug, since error happens if we uncomment this
// W_DO(_ux_assure_fence_low_entry(new_page)); // this might be another SSX
int move_count = 0;
w_keystr_t split_key;
W_DO(new_page.format_foster_child(page, new_page_id, triggering_key, split_key,
move_count));
w_assert0(move_count > 0);
// DBG5(<< "NEW FOSTER CHILD " << new_page);
/*
* Step 3: Delete moved records and update foster child pointer and high
* fence on overflowing page. Foster parent is not recompressed after
* moving records (CS TODO)
*/
page.delete_range(page.nrecs() - move_count, page.nrecs());
// DBG5(<< "AFTER RANGE DELETE " << page);
w_keystr_t new_chain;
new_page.copy_chain_fence_high_key(new_chain);
bool foster_set =
page.set_foster_child(new_page_id, split_key, new_chain);
w_assert0(foster_set);
/*
* Step 4: Update parent pointers of the moved records. The new foster
* child will have the correct parent set by the fix call above. This is
* only required because of swizzling.
*/
// set parent pointer on hash table
// smlevel_0::bf->switch_parent(new_page_id, page.get_generic_page());
// set parent pointer for children that moved to new page
int max_slot = new_page.max_child_slot();
for (general_recordid_t i = GeneralRecordIds::FOSTER_CHILD; i <= max_slot; ++i)
{
// CS TODO: Slot 1 (which is actually 0 in the internal page
// representation) is not used when inserting into an empty node (see
// my comment on btree_page_h.cpp::insert_nonghost), so in *some*
// cases, the slot i=1 will yield and invalid page in switch_parent
// below. Because of this great design feature, switch_parent has to
// cope with an invalid page.
smlevel_0::bf->switch_parent(*new_page.child_slot_address(i),
new_page.get_generic_page());
}
/*
* Step 5: Log bulk deletion and foster update on parent
*/
W_DO(log_btree_split(new_page, page, move_count, split_key, new_chain));
w_assert1(new_page.get_page_lsn() != lsn_t::null);
// hint for subsequent accesses
increase_forster_child(page.pid());
W_DO (sxs.end_sys_xct (RCOK));
DBG1(<< "Split page " << page.pid() << " into " << new_page_id);
return RCOK;
}
