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Diffstat (limited to 'innobase/include/btr0pcur.h')
| -rw-r--r-- | innobase/include/btr0pcur.h | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/innobase/include/btr0pcur.h b/innobase/include/btr0pcur.h new file mode 100644 index 00000000000..c07d5199d8c --- /dev/null +++ b/innobase/include/btr0pcur.h @@ -0,0 +1,486 @@ +/****************************************************** +The index tree persistent cursor + +(c) 1996 Innobase Oy + +Created 2/23/1996 Heikki Tuuri +*******************************************************/ + +#ifndef btr0pcur_h +#define btr0pcur_h + +#include "univ.i" +#include "dict0dict.h" +#include "data0data.h" +#include "mtr0mtr.h" +#include "page0cur.h" +#include "btr0cur.h" +#include "btr0btr.h" +#include "btr0types.h" + +/* Relative positions for a stored cursor position */ +#define BTR_PCUR_ON 1 +#define BTR_PCUR_BEFORE 2 +#define BTR_PCUR_AFTER 3 + +/****************************************************************** +Allocates memory for a persistent cursor object and initializes the cursor. */ + +btr_pcur_t* +btr_pcur_create_for_mysql(void); +/*============================*/ + /* out, own: persistent cursor */ +/****************************************************************** +Frees the memory for a persistent cursor object. */ + +void +btr_pcur_free_for_mysql( +/*====================*/ + btr_pcur_t* cursor); /* in, own: persistent cursor */ +/****************************************************************** +Copies the stored position of a pcur to another pcur. */ + +void +btr_pcur_copy_stored_position( +/*==========================*/ + btr_pcur_t* pcur_receive, /* in: pcur which will receive the + position info */ + btr_pcur_t* pcur_donate); /* in: pcur from which the info is + copied */ +/****************************************************************** +Sets the old_rec_buf field to NULL. */ +UNIV_INLINE +void +btr_pcur_init( +/*==========*/ + btr_pcur_t* pcur); /* in: persistent cursor */ +/****************************************************************** +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 */ +/****************************************************************** +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, ... */ + 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 */ +/********************************************************************* +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 */ +/****************************************************************** +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 */ +/****************************************************************** +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 */ +/****************************************************************** +If mode is PAGE_CUR_G or PAGE_CUR_GE, opens a persistent cursor on the first +user record satisfying the search condition, in the case PAGE_CUR_L or +PAGE_CUR_LE, on the last user record. If no such user record exists, then +in the first case sets the cursor after last in tree, and in the latter case +before first in tree. The latching mode must be BTR_SEARCH_LEAF or +BTR_MODIFY_LEAF. */ + +void +btr_pcur_open_on_user_rec( +/*======================*/ + dict_index_t* index, /* in: index */ + dtuple_t* tuple, /* in: tuple on which search done */ + ulint mode, /* in: PAGE_CUR_L, ... */ + ulint latch_mode, /* in: BTR_SEARCH_LEAF or + BTR_MODIFY_LEAF */ + btr_pcur_t* cursor, /* in: memory buffer for persistent + cursor */ + mtr_t* mtr); /* in: mtr */ +/************************************************************************** +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 */ +/****************************************************************** +Frees the possible old_rec_buf buffer 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 */ +/****************************************************************** +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. NOTE that the page where the cursor is positioned +must not be empty! */ + +void +btr_pcur_store_position( +/*====================*/ + btr_pcur_t* cursor, /* in: persistent cursor */ + mtr_t* mtr); /* in: mtr */ +/****************************************************************** +If the latch mode of the cursor is BTR_LEAF_SEARCH or BTR_LEAF_MODIFY, +releases the page latch and bufferfix reserved by the cursor. +NOTE! In the case of BTR_LEAF_MODIFY, there should not exist changes +made by the current mini-transaction to the data protected by the +cursor latch, as then the latch must not be released until mtr_commit. */ + +void +btr_pcur_release_leaf( +/*==================*/ + btr_pcur_t* cursor, /* in: persistent cursor */ + mtr_t* mtr); /* in: mtr */ +/************************************************************* +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 */ +/****************************************************************** +Restores the stored position of a persistent cursor bufferfixing the page and +obtaining the specified latches. If the cursor position was saved when the +(1) cursor was positioned on a user record: this function restores the position +to the last record LESS OR EQUAL to the stored record; +(2) cursor was positioned on a page infimum record: restores the position to +the last record LESS than the user record which was the successor of the page +infimum; +(3) cursor was positioned on the page supremum: restores to the first record +GREATER than the user record which was the predecessor of the supremum. */ + +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 */ +/************************************************************* +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 */ +/************************************************************* +Gets the mtr field for a pcur. */ +UNIV_INLINE +mtr_t* +btr_pcur_get_mtr( +/*=============*/ + /* out: mtr */ + btr_pcur_t* cursor); /* in: persistent cursor */ +/****************************************************************** +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 */ +/****************************************************************** +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 */ +/****************************************************************** +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 */ +/************************************************************* +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 */ +/************************************************************* +Moves the persistent cursor to the previous record in the tree. If no records +are left, the cursor stays 'before first in tree'. */ + +ibool +btr_pcur_move_to_prev( +/*==================*/ + /* out: TRUE if the cursor was not before first + in tree */ + btr_pcur_t* cursor, /* in: persistent cursor; NOTE that the + function may release the page latch */ + mtr_t* mtr); /* in: mtr */ +/************************************************************* +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 */ +/************************************************************* +Moves the persistent cursor to the first record on the next page. +Releases the latch on the current page, and bufferunfixes it. +Note that there must not be modifications on the current page, +as then the x-latch can be released only in mtr_commit. */ + +void +btr_pcur_move_to_next_page( +/*=======================*/ + btr_pcur_t* cursor, /* in: persistent cursor; must be on the + last record of the current page */ + mtr_t* mtr); /* in: mtr */ +/************************************************************* +Moves the persistent cursor backward if it is on the first record +of the page. Releases the latch on the current page, and bufferunfixes +it. Note that to prevent a possible deadlock, the operation first +stores the position of the cursor, releases the leaf latch, acquires +necessary latches and restores the cursor position again before returning. +The alphabetical position of the cursor is guaranteed to be sensible +on return, but it may happen that the cursor is not positioned on the +last record of any page, because the structure of the tree may have +changed while the cursor had no latches. */ + +void +btr_pcur_move_backward_from_page( +/*=============================*/ + btr_pcur_t* cursor, /* in: persistent cursor, must be on the + first record of the current page */ + mtr_t* mtr); /* in: 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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ +/************************************************************* +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 */ + + +/* The persistent B-tree cursor structure. This is used mainly for SQL +selects, updates, and deletes. */ + +struct btr_pcur_struct{ + btr_cur_t btr_cur; /* a B-tree cursor */ + ulint latch_mode; /* see FIXME note below! + BTR_SEARCH_LEAF, BTR_MODIFY_LEAF, + BTR_MODIFY_TREE, or BTR_NO_LATCHES, + depending on the latching state of + the page and tree where the cursor is + positioned; the last value means that + the cursor is not currently positioned: + we say then that the cursor is + detached; it can be restored to + attached if the old position was + stored in old_rec */ + ulint old_stored; /* BTR_PCUR_OLD_STORED + or BTR_PCUR_OLD_NOT_STORED */ + rec_t* old_rec; /* if cursor position is stored, + contains an initial segment of the + latest record cursor was positioned + either on, before, or after */ + ulint rel_pos; /* BTR_PCUR_ON, BTR_PCUR_BEFORE, or + BTR_PCUR_AFTER, depending on whether + cursor was on, before, or after the + old_rec record */ + dulint modify_clock; /* the modify clock value of the + buffer block when the cursor position + was stored */ + ulint pos_state; /* see FIXME note below! + BTR_PCUR_IS_POSITIONED, + BTR_PCUR_WAS_POSITIONED, + BTR_PCUR_NOT_POSITIONED */ + ulint search_mode; /* PAGE_CUR_G, ... */ + /*-----------------------------*/ + /* NOTE that the following fields may possess dynamically allocated + memory, which should be freed if not needed anymore! */ + + mtr_t* mtr; /* NULL, or this field may contain + a mini-transaction which holds the + latch on the cursor page */ + byte* old_rec_buf; /* NULL, or a dynamically allocated + buffer for old_rec */ + ulint buf_size; /* old_rec_buf size if old_rec_buf + is not NULL */ +}; + +#define BTR_PCUR_IS_POSITIONED 1997660512 /* FIXME: currently, the state + can be BTR_PCUR_IS_POSITIONED, + though it really should be + BTR_PCUR_WAS_POSITIONED, + because we have no obligation + to commit the cursor with + mtr; similarly latch_mode may + be out of date */ +#define BTR_PCUR_WAS_POSITIONED 1187549791 +#define BTR_PCUR_NOT_POSITIONED 1328997689 + +#define BTR_PCUR_OLD_STORED 908467085 +#define BTR_PCUR_OLD_NOT_STORED 122766467 + +#ifndef UNIV_NONINL +#include "btr0pcur.ic" +#endif + +#endif |