btr0pcur.ic
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上传日期:2022-05-23
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文件大小:17k
- /******************************************************
- The index tree persistent cursor
- (c) 1996 Innobase Oy
- Created 2/23/1996 Heikki Tuuri
- *******************************************************/
- /*************************************************************
- Gets the rel_pos field for a cursor whose position has been stored. */
- UNIV_INLINE
- ulint
- btr_pcur_get_rel_pos(
- /*=================*/
- /* out: BTR_PCUR_ON, ... */
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- ut_ad(cursor);
- ut_ad(cursor->old_rec);
- ut_ad(cursor->old_stored == BTR_PCUR_OLD_STORED);
- ut_ad(cursor->pos_state == BTR_PCUR_WAS_POSITIONED
- || cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- return(cursor->rel_pos);
- }
- /*************************************************************
- Sets the mtr field for a pcur. */
- UNIV_INLINE
- void
- btr_pcur_set_mtr(
- /*=============*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in, own: mtr */
- {
- ut_ad(cursor);
- cursor->mtr = mtr;
- }
- /*************************************************************
- Gets the mtr field for a pcur. */
- UNIV_INLINE
- mtr_t*
- btr_pcur_get_mtr(
- /*=============*/
- /* out: mtr */
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- ut_ad(cursor);
- return(cursor->mtr);
- }
- /*************************************************************
- Returns the btr cursor component of a persistent cursor. */
- UNIV_INLINE
- btr_cur_t*
- btr_pcur_get_btr_cur(
- /*=================*/
- /* out: pointer to btr cursor component */
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- return(&(cursor->btr_cur));
- }
- /*************************************************************
- Returns the page cursor component of a persistent cursor. */
- UNIV_INLINE
- page_cur_t*
- btr_pcur_get_page_cur(
- /*==================*/
- /* out: pointer to page cursor component */
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- return(btr_cur_get_page_cur(&(cursor->btr_cur)));
- }
- /*************************************************************
- Returns the page of a persistent cursor. */
- UNIV_INLINE
- page_t*
- btr_pcur_get_page(
- /*==============*/
- /* out: pointer to the page */
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- return(page_cur_get_page(btr_pcur_get_page_cur(cursor)));
- }
- /*************************************************************
- Returns the record of a persistent cursor. */
- UNIV_INLINE
- rec_t*
- btr_pcur_get_rec(
- /*=============*/
- /* out: pointer to the record */
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- return(page_cur_get_rec(btr_pcur_get_page_cur(cursor)));
- }
- /******************************************************************
- Gets the up_match value for a pcur after a search. */
- UNIV_INLINE
- ulint
- btr_pcur_get_up_match(
- /*==================*/
- /* out: number of matched fields at the cursor
- or to the right if search mode was PAGE_CUR_GE,
- otherwise undefined */
- btr_pcur_t* cursor) /* in: memory buffer for persistent cursor */
- {
- btr_cur_t* btr_cursor;
- ut_ad((cursor->pos_state == BTR_PCUR_WAS_POSITIONED)
- || (cursor->pos_state == BTR_PCUR_IS_POSITIONED));
- btr_cursor = btr_pcur_get_btr_cur(cursor);
- ut_ad(btr_cursor->up_match != ULINT_UNDEFINED);
- return(btr_cursor->up_match);
- }
- /******************************************************************
- Gets the low_match value for a pcur after a search. */
- UNIV_INLINE
- ulint
- btr_pcur_get_low_match(
- /*===================*/
- /* out: number of matched fields at the cursor
- or to the right if search mode was PAGE_CUR_LE,
- otherwise undefined */
- btr_pcur_t* cursor) /* in: memory buffer for persistent cursor */
- {
- btr_cur_t* btr_cursor;
- ut_ad((cursor->pos_state == BTR_PCUR_WAS_POSITIONED)
- || (cursor->pos_state == BTR_PCUR_IS_POSITIONED));
- btr_cursor = btr_pcur_get_btr_cur(cursor);
- ut_ad(btr_cursor->low_match != ULINT_UNDEFINED);
- return(btr_cursor->low_match);
- }
- /*************************************************************
- Checks if the persistent cursor is after the last user record on
- a page. */
- UNIV_INLINE
- ibool
- btr_pcur_is_after_last_on_page(
- /*===========================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- UT_NOT_USED(mtr);
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- return(page_cur_is_after_last(btr_pcur_get_page_cur(cursor)));
- }
- /*************************************************************
- Checks if the persistent cursor is before the first user record on
- a page. */
- UNIV_INLINE
- ibool
- btr_pcur_is_before_first_on_page(
- /*=============================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- UT_NOT_USED(mtr);
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- return(page_cur_is_before_first(btr_pcur_get_page_cur(cursor)));
- }
- /*************************************************************
- Checks if the persistent cursor is on a user record. */
- UNIV_INLINE
- ibool
- btr_pcur_is_on_user_rec(
- /*====================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- if ((btr_pcur_is_before_first_on_page(cursor, mtr))
- || (btr_pcur_is_after_last_on_page(cursor, mtr))) {
- return(FALSE);
- }
- return(TRUE);
- }
- /*************************************************************
- Checks if the persistent cursor is before the first user record in
- the index tree. */
- UNIV_INLINE
- ibool
- btr_pcur_is_before_first_in_tree(
- /*=============================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- if (btr_page_get_prev(btr_pcur_get_page(cursor), mtr) != FIL_NULL) {
- return(FALSE);
- }
- return(page_cur_is_before_first(btr_pcur_get_page_cur(cursor)));
- }
- /*************************************************************
- Checks if the persistent cursor is after the last user record in
- the index tree. */
- UNIV_INLINE
- ibool
- btr_pcur_is_after_last_in_tree(
- /*===========================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- if (btr_page_get_next(btr_pcur_get_page(cursor), mtr) != FIL_NULL) {
- return(FALSE);
- }
- return(page_cur_is_after_last(btr_pcur_get_page_cur(cursor)));
- }
- /*************************************************************
- Moves the persistent cursor to the next record on the same page. */
- UNIV_INLINE
- void
- btr_pcur_move_to_next_on_page(
- /*==========================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- UT_NOT_USED(mtr);
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- page_cur_move_to_next(btr_pcur_get_page_cur(cursor));
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
- }
- /*************************************************************
- Moves the persistent cursor to the previous record on the same page. */
- UNIV_INLINE
- void
- btr_pcur_move_to_prev_on_page(
- /*==========================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- UT_NOT_USED(mtr);
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- page_cur_move_to_prev(btr_pcur_get_page_cur(cursor));
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
- }
- /*************************************************************
- Moves the persistent cursor to the last record on the same page. */
- UNIV_INLINE
- void
- btr_pcur_move_to_last_on_page(
- /*==========================*/
- btr_pcur_t* cursor, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- UT_NOT_USED(mtr);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
-
- page_cur_set_after_last(buf_frame_align(btr_pcur_get_rec(cursor)),
- btr_pcur_get_page_cur(cursor));
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
- }
- /*************************************************************
- Moves the persistent cursor to the next user record in the tree. If no user
- records are left, the cursor ends up 'after last in tree'. */
- UNIV_INLINE
- ibool
- btr_pcur_move_to_next_user_rec(
- /*===========================*/
- /* out: TRUE if the cursor moved forward,
- ending on a user record */
- btr_pcur_t* cursor, /* in: persistent cursor; NOTE that the
- function may release the page latch */
- mtr_t* mtr) /* in: mtr */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
- loop:
- if (btr_pcur_is_after_last_on_page(cursor, mtr)) {
- if (btr_pcur_is_after_last_in_tree(cursor, mtr)) {
- return(FALSE);
- }
- btr_pcur_move_to_next_page(cursor, mtr);
- } else {
- btr_pcur_move_to_next_on_page(cursor, mtr);
- }
- if (btr_pcur_is_on_user_rec(cursor, mtr)) {
- return(TRUE);
- }
- goto loop;
- }
- /*************************************************************
- Moves the persistent cursor to the next record in the tree. If no records are
- left, the cursor stays 'after last in tree'. */
- UNIV_INLINE
- ibool
- btr_pcur_move_to_next(
- /*==================*/
- /* out: TRUE if the cursor was not after last
- in tree */
- btr_pcur_t* cursor, /* in: persistent cursor; NOTE that the
- function may release the page latch */
- mtr_t* mtr) /* in: mtr */
- {
- ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
- ut_ad(cursor->latch_mode != BTR_NO_LATCHES);
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
-
- if (btr_pcur_is_after_last_on_page(cursor, mtr)) {
- if (btr_pcur_is_after_last_in_tree(cursor, mtr)) {
- return(FALSE);
- }
-
- btr_pcur_move_to_next_page(cursor, mtr);
- return(TRUE);
- }
- btr_pcur_move_to_next_on_page(cursor, mtr);
- return(TRUE);
- }
- /******************************************************************
- Commits the pcur mtr and sets the pcur latch mode to BTR_NO_LATCHES,
- that is, the cursor becomes detached. If there have been modifications
- to the page where pcur is positioned, this can be used instead of
- btr_pcur_release_leaf. Function btr_pcur_store_position should be used
- before calling this, if restoration of cursor is wanted later. */
- UNIV_INLINE
- void
- btr_pcur_commit(
- /*============*/
- btr_pcur_t* pcur) /* in: persistent cursor */
- {
- ut_a(pcur->pos_state == BTR_PCUR_IS_POSITIONED);
- pcur->latch_mode = BTR_NO_LATCHES;
- mtr_commit(pcur->mtr);
- pcur->pos_state = BTR_PCUR_WAS_POSITIONED;
- }
- /******************************************************************
- Differs from btr_pcur_commit in that we can specify the mtr to commit. */
- UNIV_INLINE
- void
- btr_pcur_commit_specify_mtr(
- /*========================*/
- btr_pcur_t* pcur, /* in: persistent cursor */
- mtr_t* mtr) /* in: mtr to commit */
- {
- ut_a(pcur->pos_state == BTR_PCUR_IS_POSITIONED);
- pcur->latch_mode = BTR_NO_LATCHES;
- mtr_commit(mtr);
- pcur->pos_state = BTR_PCUR_WAS_POSITIONED;
- }
- /******************************************************************
- Sets the pcur latch mode to BTR_NO_LATCHES. */
- UNIV_INLINE
- void
- btr_pcur_detach(
- /*============*/
- btr_pcur_t* pcur) /* in: persistent cursor */
- {
- ut_a(pcur->pos_state == BTR_PCUR_IS_POSITIONED);
-
- pcur->latch_mode = BTR_NO_LATCHES;
- pcur->pos_state = BTR_PCUR_WAS_POSITIONED;
- }
- /******************************************************************
- Tests if a cursor is detached: that is the latch mode is BTR_NO_LATCHES. */
- UNIV_INLINE
- ibool
- btr_pcur_is_detached(
- /*=================*/
- /* out: TRUE if detached */
- btr_pcur_t* pcur) /* in: persistent cursor */
- {
- if (pcur->latch_mode == BTR_NO_LATCHES) {
- return(TRUE);
- }
- return(FALSE);
- }
- /******************************************************************
- Sets the old_rec_buf field to NULL. */
- UNIV_INLINE
- void
- btr_pcur_init(
- /*==========*/
- btr_pcur_t* pcur) /* in: persistent cursor */
- {
- pcur->old_stored = BTR_PCUR_OLD_NOT_STORED;
- pcur->old_rec_buf = NULL;
- pcur->old_rec = NULL;
- }
- /******************************************************************
- Initializes and opens a persistent cursor to an index tree. It should be
- closed with btr_pcur_close. */
- UNIV_INLINE
- void
- btr_pcur_open(
- /*==========*/
- dict_index_t* index, /* in: index */
- dtuple_t* tuple, /* in: tuple on which search done */
- ulint mode, /* in: PAGE_CUR_L, ...;
- NOTE that if the search is made using a unique
- prefix of a record, mode should be
- PAGE_CUR_LE, not PAGE_CUR_GE, as the latter
- may end up on the previous page from the
- record! */
- ulint latch_mode,/* in: BTR_SEARCH_LEAF, ... */
- btr_pcur_t* cursor, /* in: memory buffer for persistent cursor */
- mtr_t* mtr) /* in: mtr */
- {
- btr_cur_t* btr_cursor;
- /* Initialize the cursor */
- btr_pcur_init(cursor);
- cursor->latch_mode = latch_mode;
- cursor->search_mode = mode;
-
- /* Search with the tree cursor */
- btr_cursor = btr_pcur_get_btr_cur(cursor);
- btr_cur_search_to_nth_level(index, 0, tuple, mode, latch_mode,
- btr_cursor, 0, mtr);
- cursor->pos_state = BTR_PCUR_IS_POSITIONED;
- cursor->trx_if_known = NULL;
- }
- /******************************************************************
- Opens an persistent cursor to an index tree without initializing the
- cursor. */
- UNIV_INLINE
- void
- btr_pcur_open_with_no_init(
- /*=======================*/
- dict_index_t* index, /* in: index */
- dtuple_t* tuple, /* in: tuple on which search done */
- ulint mode, /* in: PAGE_CUR_L, ...;
- NOTE that if the search is made using a unique
- prefix of a record, mode should be
- PAGE_CUR_LE, not PAGE_CUR_GE, as the latter
- may end up on the previous page of the
- record! */
- ulint latch_mode,/* in: BTR_SEARCH_LEAF, ...;
- NOTE that if has_search_latch != 0 then
- we maybe do not acquire a latch on the cursor
- page, but assume that the caller uses his
- btr search latch to protect the record! */
- btr_pcur_t* cursor, /* in: memory buffer for persistent cursor */
- ulint has_search_latch,/* in: latch mode the caller
- currently has on btr_search_latch:
- RW_S_LATCH, or 0 */
- mtr_t* mtr) /* in: mtr */
- {
- btr_cur_t* btr_cursor;
- cursor->latch_mode = latch_mode;
- cursor->search_mode = mode;
-
- /* Search with the tree cursor */
- btr_cursor = btr_pcur_get_btr_cur(cursor);
- btr_cur_search_to_nth_level(index, 0, tuple, mode, latch_mode,
- btr_cursor, has_search_latch, mtr);
- cursor->pos_state = BTR_PCUR_IS_POSITIONED;
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
- cursor->trx_if_known = NULL;
- }
- /*********************************************************************
- Opens a persistent cursor at either end of an index. */
- UNIV_INLINE
- void
- btr_pcur_open_at_index_side(
- /*========================*/
- ibool from_left, /* in: TRUE if open to the low end,
- FALSE if to the high end */
- dict_index_t* index, /* in: index */
- ulint latch_mode, /* in: latch mode */
- btr_pcur_t* pcur, /* in: cursor */
- ibool do_init, /* in: TRUE if should be initialized */
- mtr_t* mtr) /* in: mtr */
- {
- pcur->latch_mode = latch_mode;
- if (from_left) {
- pcur->search_mode = PAGE_CUR_G;
- } else {
- pcur->search_mode = PAGE_CUR_L;
- }
- if (do_init) {
- btr_pcur_init(pcur);
- }
- btr_cur_open_at_index_side(from_left, index, latch_mode,
- btr_pcur_get_btr_cur(pcur), mtr);
- pcur->pos_state = BTR_PCUR_IS_POSITIONED;
- pcur->old_stored = BTR_PCUR_OLD_NOT_STORED;
- pcur->trx_if_known = NULL;
- }
- /**************************************************************************
- Positions a cursor at a randomly chosen position within a B-tree. */
- UNIV_INLINE
- void
- btr_pcur_open_at_rnd_pos(
- /*=====================*/
- dict_index_t* index, /* in: index */
- ulint latch_mode, /* in: BTR_SEARCH_LEAF, ... */
- btr_pcur_t* cursor, /* in/out: B-tree pcur */
- mtr_t* mtr) /* in: mtr */
- {
- /* Initialize the cursor */
- cursor->latch_mode = latch_mode;
- cursor->search_mode = PAGE_CUR_G;
-
- btr_pcur_init(cursor);
- btr_cur_open_at_rnd_pos(index, latch_mode,
- btr_pcur_get_btr_cur(cursor), mtr);
- cursor->pos_state = BTR_PCUR_IS_POSITIONED;
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
- cursor->trx_if_known = NULL;
- }
-
- /******************************************************************
- Frees the possible memory heap of a persistent cursor and sets the latch
- mode of the persistent cursor to BTR_NO_LATCHES. */
- UNIV_INLINE
- void
- btr_pcur_close(
- /*===========*/
- btr_pcur_t* cursor) /* in: persistent cursor */
- {
- if (cursor->old_rec_buf != NULL) {
- mem_free(cursor->old_rec_buf);
- cursor->old_rec = NULL;
- cursor->old_rec_buf = NULL;
- }
- cursor->btr_cur.page_cur.rec = NULL;
- cursor->old_rec = NULL;
- cursor->old_stored = BTR_PCUR_OLD_NOT_STORED;
-
- cursor->latch_mode = BTR_NO_LATCHES;
- cursor->pos_state = BTR_PCUR_NOT_POSITIONED;
- cursor->trx_if_known = NULL;
- }