static ham_status_t
__insert_split(ham_page_t *page, ham_key_t *key,
ham_offset_t rid, insert_scratchpad_t *scratchpad,
insert_hints_t *hints)
{
int cmp;
ham_status_t st;
ham_page_t *newpage, *oldsib;
int_key_t *nbte, *obte;
btree_node_t *nbtp, *obtp, *sbtp;
ham_size_t count, keysize;
ham_db_t *db=page_get_owner(page);
ham_env_t *env = db_get_env(db);
ham_key_t pivotkey, oldkey;
ham_offset_t pivotrid;
ham_u16_t pivot;
ham_bool_t pivot_at_end=HAM_FALSE;
ham_assert(page_get_owner(page), (0));
ham_assert(device_get_env(page_get_device(page))
== db_get_env(page_get_owner(page)), (0));
ham_assert(hints->force_append == HAM_FALSE, (0));
keysize=db_get_keysize(db);
/*
* allocate a new page
*/
hints->cost++;
st=db_alloc_page(&newpage, db, PAGE_TYPE_B_INDEX, 0);
ham_assert(st ? page == NULL : 1, (0));
ham_assert(!st ? page != NULL : 1, (0));
if (st)
return st;
ham_assert(page_get_owner(newpage), (""));
/* clear the node header */
memset(page_get_payload(newpage), 0, sizeof(btree_node_t));
stats_page_is_nuked(db, page, HAM_TRUE);
/*
* move half of the key/rid-tuples to the new page
*
* !! recno: keys are sorted; we do a "lazy split"
*/
nbtp=ham_page_get_btree_node(newpage);
nbte=btree_node_get_key(db, nbtp, 0);
obtp=ham_page_get_btree_node(page);
obte=btree_node_get_key(db, obtp, 0);
count=btree_node_get_count(obtp);
/*
* for databases with sequential access (this includes recno databases):
* do not split in the middle, but at the very end of the page
*
* if this page is the right-most page in the index, and this key is
* inserted at the very end, then we select the same pivot as for
* sequential access
*/
if (db_get_data_access_mode(db)&HAM_DAM_SEQUENTIAL_INSERT)
pivot_at_end=HAM_TRUE;
else if (btree_node_get_right(obtp)==0) {
cmp=key_compare_pub_to_int(db, page, key, btree_node_get_count(obtp)-1);
if (cmp>0)
pivot_at_end=HAM_TRUE;
}
/*
* internal pages set the count of the new page to count-pivot-1 (because
* the pivot element will become ptr_left of the new page).
* by using pivot=count-2 we make sure that at least 1 element will remain
* in the new node.
*/
if (pivot_at_end) {
pivot=count-2;
}
else {
pivot=count/2;
}
/*
* uncouple all cursors
*/
st=bt_uncouple_all_cursors(page, pivot);
if (st)
return (st);
/*
* if we split a leaf, we'll insert the pivot element in the leaf
* page, too. in internal nodes, we don't insert it, but propagate
* it to the parent node only.
*/
if (btree_node_is_leaf(obtp)) {
hints->cost += stats_memmove_cost((db_get_int_key_header_size()+keysize)*(count-pivot));
memcpy((char *)nbte,
((char *)obte)+(db_get_int_key_header_size()+keysize)*pivot,
(db_get_int_key_header_size()+keysize)*(count-pivot));
}
else {
hints->cost += stats_memmove_cost((db_get_int_key_header_size()+keysize)*(count-pivot-1));
memcpy((char *)nbte,
((char *)obte)+(db_get_int_key_header_size()+keysize)*(pivot+1),
(db_get_int_key_header_size()+keysize)*(count-pivot-1));
}
/*
* store the pivot element, we'll need it later to propagate it
* to the parent page
*/
nbte=btree_node_get_key(db, obtp, pivot);
memset(&pivotkey, 0, sizeof(pivotkey));
memset(&oldkey, 0, sizeof(oldkey));
oldkey.data=key_get_key(nbte);
oldkey.size=key_get_size(nbte);
oldkey._flags=key_get_flags(nbte);
st = util_copy_key(db, &oldkey, &pivotkey);
if (st)
{
(void)db_free_page(newpage, DB_MOVE_TO_FREELIST);
goto fail_dramatically;
}
pivotrid=page_get_self(newpage);
/*
* adjust the page count
*/
if (btree_node_is_leaf(obtp)) {
btree_node_set_count(obtp, pivot);
btree_node_set_count(nbtp, count-pivot);
}
else {
btree_node_set_count(obtp, pivot);
btree_node_set_count(nbtp, count-pivot-1);
}
/*
* if we're in an internal page: fix the ptr_left of the new page
* (it points to the ptr of the pivot key)
*/
if (!btree_node_is_leaf(obtp)) {
/*
* nbte still contains the pivot key
*/
btree_node_set_ptr_left(nbtp, key_get_ptr(nbte));
}
/*
* insert the new element
*/
hints->cost++;
cmp=key_compare_pub_to_int(db, page, key, pivot);
if (cmp < -1)
{
st = (ham_status_t)cmp;
goto fail_dramatically;
}
if (cmp>=0)
st=__insert_nosplit(newpage, key, rid,
scratchpad->record, scratchpad->cursor, hints);
else
st=__insert_nosplit(page, key, rid,
scratchpad->record, scratchpad->cursor, hints);
if (st)
{
goto fail_dramatically;
}
scratchpad->cursor=0; /* don't overwrite cursor if __insert_nosplit
is called again */
/*
* fix the double-linked list of pages, and mark the pages as dirty
*/
if (btree_node_get_right(obtp))
{
st=db_fetch_page(&oldsib, db, btree_node_get_right(obtp), 0);
if (st)
goto fail_dramatically;
}
else
{
oldsib=0;
}
if (oldsib) {
st=ham_log_add_page_before(oldsib);
if (st)
goto fail_dramatically;
}
btree_node_set_left (nbtp, page_get_self(page));
btree_node_set_right(nbtp, btree_node_get_right(obtp));
btree_node_set_right(obtp, page_get_self(newpage));
if (oldsib) {
sbtp=ham_page_get_btree_node(oldsib);
btree_node_set_left(sbtp, page_get_self(newpage));
page_set_dirty(oldsib, env);
}
page_set_dirty(newpage, env);
page_set_dirty(page, env);
/*
* propagate the pivot key to the parent page
*/
ham_assert(!(scratchpad->key.flags & HAM_KEY_USER_ALLOC), (0));
if (scratchpad->key.data)
allocator_free(env_get_allocator(env), scratchpad->key.data);
scratchpad->key=pivotkey;
scratchpad->rid=pivotrid;
ham_assert(!(scratchpad->key.flags & HAM_KEY_USER_ALLOC), (0));
return (SPLIT);
fail_dramatically:
ham_assert(!(pivotkey.flags & HAM_KEY_USER_ALLOC), (0));
if (pivotkey.data)
allocator_free(env_get_allocator(env), pivotkey.data);
return st;
}
ham_status_t
txn_abort(ham_txn_t *txn, ham_u32_t flags)
{
ham_status_t st;
ham_env_t *env=txn_get_env(txn);
/*
* are cursors attached to this txn? if yes, fail
*/
if (txn_get_cursor_refcount(txn)) {
ham_trace(("transaction cannot be aborted till all attached "
"cursors are closed"));
return HAM_CURSOR_STILL_OPEN;
}
if (env_get_log(env) && !(txn_get_flags(txn)&HAM_TXN_READ_ONLY)) {
st=ham_log_append_txn_abort(env_get_log(env), txn);
if (st)
return st;
}
env_set_txn(env, 0);
/*
* undo all operations from this transaction
*
* this includes allocated pages (they're moved to the freelist),
* deleted pages (they're un-deleted) and other modifications (will
* re-create the original page from the logfile)
*
* keep txn_get_pagelist(txn) intact during every round, so no
* local var for this one.
*/
while (txn_get_pagelist(txn)) {
ham_page_t *head = txn_get_pagelist(txn);
if (!(flags & DO_NOT_NUKE_PAGE_STATS)) {
/*
* nuke critical statistics, such as tracked outer bounds; imagine,
* for example, a failing erase transaction which, through erasing
* the top-most key, lowers the actual upper bound, after which
* the transaction fails at some later point in life. Now if we
* wouldn't 'rewind' our bounds-statistics, we would have a
* situation where a subsequent out-of-bounds insert (~ append)
* would possibly FAIL due to the hinter using incorrect bounds
* information then!
*
* Hence we 'reverse' our statistics here and the easiest route
* is to just nuke the critical bits; subsequent find/insert/erase
* operations will ensure that the stats will get updated again,
* anyhow. All we loose then is a few subsequent operations, which
* might have been hinted if we had played a smarter game of
* statistics 'reversal'. Soit.
*/
ham_db_t *db = page_get_owner(head);
/*
* only need to do this for index pages anyhow, and those are the
* ones which have their 'ownership' set.
*/
if (db) {
stats_page_is_nuked(db, head, HAM_FALSE);
}
}
ham_assert(page_is_in_list(txn_get_pagelist(txn), head, PAGE_LIST_TXN),
(0));
txn_get_pagelist(txn) = page_list_remove(head, PAGE_LIST_TXN, head);
/* if this page was allocated by this transaction, then we can
* move the whole page to the freelist */
if (page_get_alloc_txn_id(head)==txn_get_id(txn)) {
(void)freel_mark_free(env, 0, page_get_self(head),
env_get_pagesize(env), HAM_TRUE);
}
else {
/* remove the 'delete pending' flag */
page_set_npers_flags(head,
page_get_npers_flags(head)&~PAGE_NPERS_DELETE_PENDING);
/* if the page is dirty, and RECOVERY is enabled: recreate
* the original, unmodified page from the log */
if (env_get_log(env) && page_is_dirty(head)) {
st=ham_log_recreate(env_get_log(env), head);
if (st)
return (st);
/*page_set_undirty(head); */
}
}
/* page is no longer in use */
page_release_ref(head);
}
ham_assert(txn_get_pagelist(txn)==0, (0));
return (0);
}
static ham_status_t
__insert_cursor(ham_btree_t *be, ham_key_t *key, ham_record_t *record,
ham_bt_cursor_t *cursor, insert_hints_t *hints)
{
ham_status_t st;
ham_page_t *root;
ham_db_t *db=be_get_db(be);
ham_env_t *env = db_get_env(db);
insert_scratchpad_t scratchpad;
ham_assert(hints->force_append == HAM_FALSE, (0));
ham_assert(hints->force_prepend == HAM_FALSE, (0));
/*
* initialize the scratchpad
*/
memset(&scratchpad, 0, sizeof(scratchpad));
scratchpad.be=be;
scratchpad.record=record;
scratchpad.cursor=cursor;
/*
* get the root-page...
*/
ham_assert(btree_get_rootpage(be)!=0, ("btree has no root page"));
st=db_fetch_page(&root, db, btree_get_rootpage(be), 0);
ham_assert(st ? root == NULL : 1, (0));
if (st)
return st;
/*
* ... and start the recursion
*/
st=__insert_recursive(root, key, 0, &scratchpad, hints);
/*
* if the root page was split, we have to create a new
* root page.
*/
if (st==SPLIT) {
ham_page_t *newroot;
btree_node_t *node;
/*
* the root-page will be changed...
*/
st=ham_log_add_page_before(root);
if (st)
return (st);
/*
* allocate a new root page
*/
st=db_alloc_page(&newroot, db, PAGE_TYPE_B_ROOT, 0);
ham_assert(st ? newroot == NULL : 1, (0));
if (st)
return (st);
ham_assert(page_get_owner(newroot), (""));
/* clear the node header */
memset(page_get_payload(newroot), 0, sizeof(btree_node_t));
stats_page_is_nuked(db, root, HAM_TRUE);
/*
* insert the pivot element and the ptr_left
*/
node=ham_page_get_btree_node(newroot);
btree_node_set_ptr_left(node, btree_get_rootpage(be));
st=__insert_nosplit(newroot, &scratchpad.key,
scratchpad.rid, scratchpad.record, scratchpad.cursor,
hints);
ham_assert(!(scratchpad.key.flags & HAM_KEY_USER_ALLOC), (0));
scratchpad.cursor=0; /* don't overwrite cursor if __insert_nosplit
is called again */
if (st) {
ham_assert(!(scratchpad.key.flags & HAM_KEY_USER_ALLOC), (0));
if (scratchpad.key.data)
allocator_free(env_get_allocator(env), scratchpad.key.data);
return (st);
}
/*
* set the new root page
*
* !!
* do NOT delete the old root page - it's still in use!
*
* also don't forget to flush the backend - otherwise the header
* page of the database will not contain the updated information.
* The backend is flushed when the database is closed, but if
* recovery is enabled then the flush here is critical.
*/
btree_set_rootpage(be, page_get_self(newroot));
be_set_dirty(be, HAM_TRUE);
be->_fun_flush(be);
/*
* As we re-purpose a page, we will reset its pagecounter
* as well to signal its first use as the new type assigned
* here.
*/
if (env_get_cache(env) && (page_get_type(root)!=PAGE_TYPE_B_INDEX))
cache_update_page_access_counter(root, env_get_cache(env), 0);
page_set_type(root, PAGE_TYPE_B_INDEX);
page_set_dirty(root, env);
page_set_dirty(newroot, env);
/* the root page was modified (btree_set_rootpage) - make sure that
* it's logged */
if (env_get_rt_flags(env)&HAM_ENABLE_RECOVERY) {
st=txn_add_page(env_get_txn(env), env_get_header_page(env),
HAM_TRUE);
if (st)
return (st);
}
}
/*
* release the scratchpad-memory and return to caller
*/
ham_assert(!(scratchpad.key.flags & HAM_KEY_USER_ALLOC), (0));
if (scratchpad.key.data)
allocator_free(env_get_allocator(env), scratchpad.key.data);
return (st);
}
