void
btr_pcur_release_leaf(
/*==================*/
btr_pcur_t* cursor, /* in: persistent cursor */
mtr_t* mtr) /* in: mtr */
{
page_t* page;
ut_a(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
page = btr_cur_get_page(btr_pcur_get_btr_cur(cursor));
btr_leaf_page_release(page, cursor->latch_mode, mtr);
cursor->latch_mode = BTR_NO_LATCHES;
cursor->pos_state = BTR_PCUR_WAS_POSITIONED;
}
ibool
btr_pcur_restore_position(
/*======================*/
/* out: TRUE if the cursor position
was stored when it was on a user record
and it can be restored on a user record
whose ordering fields are identical to
the ones of the original user record */
ulint latch_mode, /* in: BTR_SEARCH_LEAF, ... */
btr_pcur_t* cursor, /* in: detached persistent cursor */
mtr_t* mtr) /* in: mtr */
{
dict_index_t* index;
page_t* page;
dtuple_t* tuple;
ulint mode;
ulint old_mode;
mem_heap_t* heap;
index = btr_cur_get_index(btr_pcur_get_btr_cur(cursor));
if (UNIV_UNLIKELY(cursor->old_stored != BTR_PCUR_OLD_STORED)
|| UNIV_UNLIKELY(cursor->pos_state != BTR_PCUR_WAS_POSITIONED
&& cursor->pos_state != BTR_PCUR_IS_POSITIONED)) {
ut_print_buf(stderr, cursor, sizeof(btr_pcur_t));
if (cursor->trx_if_known) {
trx_print(stderr, cursor->trx_if_known, 0);
}
ut_error;
}
if (UNIV_UNLIKELY(
cursor->rel_pos == BTR_PCUR_AFTER_LAST_IN_TREE
|| cursor->rel_pos == BTR_PCUR_BEFORE_FIRST_IN_TREE)) {
/* In these cases we do not try an optimistic restoration,
but always do a search */
btr_cur_open_at_index_side(
cursor->rel_pos == BTR_PCUR_BEFORE_FIRST_IN_TREE,
index, latch_mode, btr_pcur_get_btr_cur(cursor), mtr);
cursor->block_when_stored
= buf_block_align(btr_pcur_get_page(cursor));
return(FALSE);
}
ut_a(cursor->old_rec);
ut_a(cursor->old_n_fields);
page = btr_cur_get_page(btr_pcur_get_btr_cur(cursor));
if (UNIV_LIKELY(latch_mode == BTR_SEARCH_LEAF)
|| UNIV_LIKELY(latch_mode == BTR_MODIFY_LEAF)) {
/* Try optimistic restoration */
if (UNIV_LIKELY(buf_page_optimistic_get(
latch_mode,
cursor->block_when_stored, page,
cursor->modify_clock, mtr))) {
cursor->pos_state = BTR_PCUR_IS_POSITIONED;
#ifdef UNIV_SYNC_DEBUG
buf_page_dbg_add_level(page, SYNC_TREE_NODE);
#endif /* UNIV_SYNC_DEBUG */
if (cursor->rel_pos == BTR_PCUR_ON) {
#ifdef UNIV_DEBUG
rec_t* rec;
ulint* offsets1;
ulint* offsets2;
#endif /* UNIV_DEBUG */
cursor->latch_mode = latch_mode;
#ifdef UNIV_DEBUG
rec = btr_pcur_get_rec(cursor);
heap = mem_heap_create(256);
offsets1 = rec_get_offsets(
cursor->old_rec, index, NULL,
cursor->old_n_fields, &heap);
offsets2 = rec_get_offsets(
rec, index, NULL,
cursor->old_n_fields, &heap);
ut_ad(!cmp_rec_rec(cursor->old_rec,
rec, offsets1, offsets2,
index));
mem_heap_free(heap);
#endif /* UNIV_DEBUG */
return(TRUE);
}
return(FALSE);
}
}
/* If optimistic restoration did not succeed, open the cursor anew */
heap = mem_heap_create(256);
tuple = dict_index_build_data_tuple(index, cursor->old_rec,
cursor->old_n_fields, heap);
/* Save the old search mode of the cursor */
old_mode = cursor->search_mode;
switch (cursor->rel_pos) {
case BTR_PCUR_ON:
mode = PAGE_CUR_LE;
break;
case BTR_PCUR_AFTER:
mode = PAGE_CUR_G;
break;
case BTR_PCUR_BEFORE:
mode = PAGE_CUR_L;
break;
default:
ut_error;
mode = 0; /* silence a warning */
}
btr_pcur_open_with_no_init(index, tuple, mode, latch_mode,
cursor, 0, mtr);
/* Restore the old search mode */
cursor->search_mode = old_mode;
if (btr_pcur_is_on_user_rec(cursor, mtr)) {
switch (cursor->rel_pos) {
case BTR_PCUR_ON:
if (!cmp_dtuple_rec(
tuple, btr_pcur_get_rec(cursor),
rec_get_offsets(btr_pcur_get_rec(cursor),
index, NULL,
ULINT_UNDEFINED, &heap))) {
/* We have to store the NEW value for
the modify clock, since the cursor can
now be on a different page! But we can
retain the value of old_rec */
cursor->block_when_stored =
buf_block_align(
btr_pcur_get_page(cursor));
cursor->modify_clock =
buf_block_get_modify_clock(
cursor->block_when_stored);
cursor->old_stored = BTR_PCUR_OLD_STORED;
mem_heap_free(heap);
return(TRUE);
}
break;
case BTR_PCUR_BEFORE:
page_cur_move_to_next(btr_pcur_get_page_cur(cursor));
break;
case BTR_PCUR_AFTER:
page_cur_move_to_prev(btr_pcur_get_page_cur(cursor));
break;
#ifdef UNIV_DEBUG
default:
ut_error;
#endif /* UNIV_DEBUG */
}
}
mem_heap_free(heap);
/* We have to store new position information, modify_clock etc.,
to the cursor because it can now be on a different page, the record
under it may have been removed, etc. */
btr_pcur_store_position(cursor, mtr);
return(FALSE);
}
