/**************************************************************//**
The position of the cursor is stored by taking an initial segment of the
record the cursor is positioned on, before, or after, and copying it to the
cursor data structure, or just setting a flag if the cursor id before the
first in an EMPTY tree, or after the last in an EMPTY tree. NOTE that the
page where the cursor is positioned must not be empty if the index tree is
not totally empty! */
UNIV_INTERN
void
btr_pcur_store_position(
/*====================*/
btr_pcur_t* cursor, /*!< in: persistent cursor */
mtr_t* mtr) /*!< in: mtr */
{
page_cur_t* page_cursor;
buf_block_t* block;
rec_t* rec;
dict_index_t* index;
page_t* page;
ulint offs;
ut_a(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
block = btr_pcur_get_block(cursor);
if (srv_pass_corrupt_table && !block) {
return;
}
ut_a(block);
index = btr_cur_get_index(btr_pcur_get_btr_cur(cursor));
page_cursor = btr_pcur_get_page_cur(cursor);
rec = page_cur_get_rec(page_cursor);
page = page_align(rec);
offs = page_offset(rec);
ut_ad(mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_S_FIX)
|| mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
ut_a(cursor->latch_mode != BTR_NO_LATCHES);
if (UNIV_UNLIKELY(page_get_n_recs(page) == 0)) {
/* It must be an empty index tree; NOTE that in this case
we do not store the modify_clock, but always do a search
if we restore the cursor position */
ut_a(btr_page_get_next(page, mtr) == FIL_NULL);
ut_a(btr_page_get_prev(page, mtr) == FIL_NULL);
ut_ad(page_is_leaf(page));
ut_ad(page_get_page_no(page) == index->page);
cursor->old_stored = BTR_PCUR_OLD_STORED;
if (page_rec_is_supremum_low(offs)) {
cursor->rel_pos = BTR_PCUR_AFTER_LAST_IN_TREE;
} else {
cursor->rel_pos = BTR_PCUR_BEFORE_FIRST_IN_TREE;
}
return;
}
if (page_rec_is_supremum_low(offs)) {
rec = page_rec_get_prev(rec);
cursor->rel_pos = BTR_PCUR_AFTER;
} else if (page_rec_is_infimum_low(offs)) {
rec = page_rec_get_next(rec);
cursor->rel_pos = BTR_PCUR_BEFORE;
} else {
cursor->rel_pos = BTR_PCUR_ON;
}
cursor->old_stored = BTR_PCUR_OLD_STORED;
cursor->old_rec = dict_index_copy_rec_order_prefix(
index, rec, &cursor->old_n_fields,
&cursor->old_rec_buf, &cursor->buf_size);
cursor->block_when_stored = block;
cursor->modify_clock = buf_block_get_modify_clock(block);
}
dict_index_t* index;
page_t* page;
ulint offs;
ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
block = btr_pcur_get_block(cursor);
SRV_CORRUPT_TABLE_CHECK(block, return;);
index = btr_cur_get_index(btr_pcur_get_btr_cur(cursor));
page_cursor = btr_pcur_get_page_cur(cursor);
rec = page_cur_get_rec(page_cursor);
page = page_align(rec);
offs = page_offset(rec);
ut_ad(mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_S_FIX)
|| mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
if (UNIV_UNLIKELY(page_get_n_recs(page) == 0)) {
/* It must be an empty index tree; NOTE that in this case
we do not store the modify_clock, but always do a search
if we restore the cursor position */
ut_a(btr_page_get_next(page, mtr) == FIL_NULL);
ut_a(btr_page_get_prev(page, mtr) == FIL_NULL);
ut_ad(page_is_leaf(page));
ut_ad(page_get_page_no(page) == index->page);
