/***************************************************************************** Copyright (c) 1997, 2010, Innobase Oy. All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *****************************************************************************/ /**************************************************//** @file row/row0umod.c Undo modify of a row Created 2/27/1997 Heikki Tuuri *******************************************************/ #include "row0umod.h" #ifdef UNIV_NONINL #include "row0umod.ic" #endif #include "dict0dict.h" #include "dict0boot.h" #include "trx0undo.h" #include "trx0roll.h" #include "btr0btr.h" #include "mach0data.h" #include "row0undo.h" #include "row0vers.h" #include "trx0trx.h" #include "trx0rec.h" #include "row0row.h" #include "row0upd.h" #include "que0que.h" #include "log0log.h" /* Considerations on undoing a modify operation. (1) Undoing a delete marking: all index records should be found. Some of them may have delete mark already FALSE, if the delete mark operation was stopped underway, or if the undo operation ended prematurely because of a system crash. (2) Undoing an update of a delete unmarked record: the newer version of an updated secondary index entry should be removed if no prior version of the clustered index record requires its existence. Otherwise, it should be delete marked. (3) Undoing an update of a delete marked record. In this kind of update a delete marked clustered index record was delete unmarked and possibly also some of its fields were changed. Now, it is possible that the delete marked version has become obsolete at the time the undo is started. */ /************************************************************************* IMPORTANT NOTE: Any operation that generates redo MUST check that there is enough space in the redo log before for that operation. This is done by calling log_free_check(). The reason for checking the availability of the redo log space before the start of the operation is that we MUST not hold any synchonization objects when performing the check. If you make a change in this module make sure that no codepath is introduced where a call to log_free_check() is bypassed. */ /***********************************************************//** Checks if also the previous version of the clustered index record was modified or inserted by the same transaction, and its undo number is such that it should be undone in the same rollback. @return TRUE if also previous modify or insert of this row should be undone */ static ibool row_undo_mod_undo_also_prev_vers( /*=============================*/ undo_node_t* node, /*!< in: row undo node */ undo_no_t* undo_no)/*!< out: the undo number */ { trx_undo_rec_t* undo_rec; trx_t* trx; trx = node->trx; if (0 != ut_dulint_cmp(node->new_trx_id, trx->id)) { *undo_no = ut_dulint_zero; return(FALSE); } undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap); *undo_no = trx_undo_rec_get_undo_no(undo_rec); return(ut_dulint_cmp(trx->roll_limit, *undo_no) <= 0); } /***********************************************************//** Undoes a modify in a clustered index record. @return DB_SUCCESS, DB_FAIL, or error code: we may run out of file space */ static ulint row_undo_mod_clust_low( /*===================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr, /*!< in: query thread */ mtr_t* mtr, /*!< in: mtr; must be committed before latching any further pages */ ulint mode) /*!< in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */ { btr_pcur_t* pcur; btr_cur_t* btr_cur; ulint err; #ifdef UNIV_DEBUG ibool success; #endif /* UNIV_DEBUG */ pcur = &(node->pcur); btr_cur = btr_pcur_get_btr_cur(pcur); #ifdef UNIV_DEBUG success = #endif /* UNIV_DEBUG */ btr_pcur_restore_position(mode, pcur, mtr); ut_ad(success); if (mode == BTR_MODIFY_LEAF) { err = btr_cur_optimistic_update(BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG | BTR_KEEP_SYS_FLAG, btr_cur, node->update, node->cmpl_info, thr, mtr); } else { mem_heap_t* heap = NULL; big_rec_t* dummy_big_rec; ut_ad(mode == BTR_MODIFY_TREE); err = btr_cur_pessimistic_update( BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG | BTR_KEEP_SYS_FLAG, btr_cur, &heap, &dummy_big_rec, node->update, node->cmpl_info, thr, mtr); ut_a(!dummy_big_rec); if (UNIV_LIKELY_NULL(heap)) { mem_heap_free(heap); } } return(err); } /***********************************************************//** Removes a clustered index record after undo if possible. This is attempted when the record was inserted by updating a delete-marked record and there no longer exist transactions that would see the delete-marked record. In other words, we roll back the insert by purging the record. @return DB_SUCCESS, DB_FAIL, or error code: we may run out of file space */ static ulint row_undo_mod_remove_clust_low( /*==========================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr, /*!< in: query thread */ mtr_t* mtr, /*!< in: mtr */ ulint mode) /*!< in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */ { btr_pcur_t* pcur; btr_cur_t* btr_cur; ulint err; ibool success; ut_ad(node->rec_type == TRX_UNDO_UPD_DEL_REC); pcur = &(node->pcur); btr_cur = btr_pcur_get_btr_cur(pcur); success = btr_pcur_restore_position(mode, pcur, mtr); if (!success) { return(DB_SUCCESS); } /* Find out if we can remove the whole clustered index record */ if (node->rec_type == TRX_UNDO_UPD_DEL_REC && !row_vers_must_preserve_del_marked(node->new_trx_id, mtr)) { /* Ok, we can remove */ } else { return(DB_SUCCESS); } if (mode == BTR_MODIFY_LEAF) { success = btr_cur_optimistic_delete(btr_cur, mtr); if (success) { err = DB_SUCCESS; } else { err = DB_FAIL; } } else { ut_ad(mode == BTR_MODIFY_TREE); /* This operation is analogous to purge, we can free also inherited externally stored fields */ btr_cur_pessimistic_delete(&err, FALSE, btr_cur, thr_is_recv(thr) ? RB_RECOVERY_PURGE_REC : RB_NONE, mtr); /* The delete operation may fail if we have little file space left: TODO: easiest to crash the database and restart with more file space */ } return(err); } /***********************************************************//** Undoes a modify in a clustered index record. Sets also the node state for the next round of undo. @return DB_SUCCESS or error code: we may run out of file space */ static ulint row_undo_mod_clust( /*===============*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr) /*!< in: query thread */ { btr_pcur_t* pcur; mtr_t mtr; ulint err; ibool success; ibool more_vers; undo_no_t new_undo_no; ut_ad(node && thr); log_free_check(); /* Check if also the previous version of the clustered index record should be undone in this same rollback operation */ more_vers = row_undo_mod_undo_also_prev_vers(node, &new_undo_no); pcur = &(node->pcur); mtr_start(&mtr); /* Try optimistic processing of the record, keeping changes within the index page */ err = row_undo_mod_clust_low(node, thr, &mtr, BTR_MODIFY_LEAF); if (err != DB_SUCCESS) { btr_pcur_commit_specify_mtr(pcur, &mtr); /* We may have to modify tree structure: do a pessimistic descent down the index tree */ mtr_start(&mtr); err = row_undo_mod_clust_low(node, thr, &mtr, BTR_MODIFY_TREE); } btr_pcur_commit_specify_mtr(pcur, &mtr); if (err == DB_SUCCESS && node->rec_type == TRX_UNDO_UPD_DEL_REC) { mtr_start(&mtr); err = row_undo_mod_remove_clust_low(node, thr, &mtr, BTR_MODIFY_LEAF); if (err != DB_SUCCESS) { btr_pcur_commit_specify_mtr(pcur, &mtr); /* We may have to modify tree structure: do a pessimistic descent down the index tree */ mtr_start(&mtr); err = row_undo_mod_remove_clust_low(node, thr, &mtr, BTR_MODIFY_TREE); } btr_pcur_commit_specify_mtr(pcur, &mtr); } node->state = UNDO_NODE_FETCH_NEXT; trx_undo_rec_release(node->trx, node->undo_no); if (more_vers && err == DB_SUCCESS) { /* Reserve the undo log record to the prior version after committing &mtr: this is necessary to comply with the latching order, as &mtr may contain the fsp latch which is lower in the latch hierarchy than trx->undo_mutex. */ success = trx_undo_rec_reserve(node->trx, new_undo_no); if (success) { node->state = UNDO_NODE_PREV_VERS; } } return(err); } /***********************************************************//** Delete marks or removes a secondary index entry if found. @return DB_SUCCESS, DB_FAIL, or DB_OUT_OF_FILE_SPACE */ static ulint row_undo_mod_del_mark_or_remove_sec_low( /*====================================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr, /*!< in: query thread */ dict_index_t* index, /*!< in: index */ dtuple_t* entry, /*!< in: index entry */ ulint mode) /*!< in: latch mode BTR_MODIFY_LEAF or BTR_MODIFY_TREE */ { ibool found; btr_pcur_t pcur; btr_cur_t* btr_cur; ibool success; ibool old_has; ulint err; mtr_t mtr; mtr_t mtr_vers; log_free_check(); mtr_start(&mtr); found = row_search_index_entry(index, entry, mode, &pcur, &mtr); btr_cur = btr_pcur_get_btr_cur(&pcur); if (!found) { /* In crash recovery, the secondary index record may be missing if the UPDATE did not have time to insert the secondary index records before the crash. When we are undoing that UPDATE in crash recovery, the record may be missing. In normal processing, if an update ends in a deadlock before it has inserted all updated secondary index records, then the undo will not find those records. */ btr_pcur_close(&pcur); mtr_commit(&mtr); return(DB_SUCCESS); } /* We should remove the index record if no prior version of the row, which cannot be purged yet, requires its existence. If some requires, we should delete mark the record. */ mtr_start(&mtr_vers); success = btr_pcur_restore_position(BTR_SEARCH_LEAF, &(node->pcur), &mtr_vers); ut_a(success); old_has = row_vers_old_has_index_entry(FALSE, btr_pcur_get_rec(&(node->pcur)), &mtr_vers, index, entry); if (old_has) { err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG, btr_cur, TRUE, thr, &mtr); ut_ad(err == DB_SUCCESS); } else { /* Remove the index record */ if (mode == BTR_MODIFY_LEAF) { success = btr_cur_optimistic_delete(btr_cur, &mtr); if (success) { err = DB_SUCCESS; } else { err = DB_FAIL; } } else { ut_ad(mode == BTR_MODIFY_TREE); /* No need to distinguish RB_RECOVERY_PURGE here, because we are deleting a secondary index record: the distinction between RB_NORMAL and RB_RECOVERY_PURGE only matters when deleting a record that contains externally stored columns. */ ut_ad(!dict_index_is_clust(index)); btr_cur_pessimistic_delete(&err, FALSE, btr_cur, RB_NORMAL, &mtr); /* The delete operation may fail if we have little file space left: TODO: easiest to crash the database and restart with more file space */ } } btr_pcur_commit_specify_mtr(&(node->pcur), &mtr_vers); btr_pcur_close(&pcur); mtr_commit(&mtr); return(err); } /***********************************************************//** Delete marks or removes a secondary index entry if found. NOTE that if we updated the fields of a delete-marked secondary index record so that alphabetically they stayed the same, e.g., 'abc' -> 'aBc', we cannot return to the original values because we do not know them. But this should not cause problems because in row0sel.c, in queries we always retrieve the clustered index record or an earlier version of it, if the secondary index record through which we do the search is delete-marked. @return DB_SUCCESS or DB_OUT_OF_FILE_SPACE */ static ulint row_undo_mod_del_mark_or_remove_sec( /*================================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr, /*!< in: query thread */ dict_index_t* index, /*!< in: index */ dtuple_t* entry) /*!< in: index entry */ { ulint err; err = row_undo_mod_del_mark_or_remove_sec_low(node, thr, index, entry, BTR_MODIFY_LEAF); if (err == DB_SUCCESS) { return(err); } err = row_undo_mod_del_mark_or_remove_sec_low(node, thr, index, entry, BTR_MODIFY_TREE); return(err); } /***********************************************************//** Delete unmarks a secondary index entry which must be found. It might not be delete-marked at the moment, but it does not harm to unmark it anyway. We also need to update the fields of the secondary index record if we updated its fields but alphabetically they stayed the same, e.g., 'abc' -> 'aBc'. @return DB_FAIL or DB_SUCCESS or DB_OUT_OF_FILE_SPACE */ static ulint row_undo_mod_del_unmark_sec_and_undo_update( /*========================================*/ ulint mode, /*!< in: search mode: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */ que_thr_t* thr, /*!< in: query thread */ dict_index_t* index, /*!< in: index */ const dtuple_t* entry) /*!< in: index entry */ { mem_heap_t* heap; btr_pcur_t pcur; upd_t* update; ulint err = DB_SUCCESS; big_rec_t* dummy_big_rec; mtr_t mtr; trx_t* trx = thr_get_trx(thr); /* Ignore indexes that are being created. */ if (UNIV_UNLIKELY(*index->name == TEMP_INDEX_PREFIX)) { return(DB_SUCCESS); } log_free_check(); mtr_start(&mtr); if (UNIV_UNLIKELY(!row_search_index_entry(index, entry, mode, &pcur, &mtr))) { fputs("InnoDB: error in sec index entry del undo in\n" "InnoDB: ", stderr); dict_index_name_print(stderr, trx, index); fputs("\n" "InnoDB: tuple ", stderr); dtuple_print(stderr, entry); fputs("\n" "InnoDB: record ", stderr); rec_print(stderr, btr_pcur_get_rec(&pcur), index); putc('\n', stderr); trx_print(stderr, trx, 0); fputs("\n" "InnoDB: Submit a detailed bug report" " to http://bugs.mysql.com\n", stderr); } else { btr_cur_t* btr_cur = btr_pcur_get_btr_cur(&pcur); err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG, btr_cur, FALSE, thr, &mtr); ut_a(err == DB_SUCCESS); heap = mem_heap_create(100); update = row_upd_build_sec_rec_difference_binary( index, entry, btr_cur_get_rec(btr_cur), trx, heap); if (upd_get_n_fields(update) == 0) { /* Do nothing */ } else if (mode == BTR_MODIFY_LEAF) { /* Try an optimistic updating of the record, keeping changes within the page */ err = btr_cur_optimistic_update( BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG, btr_cur, update, 0, thr, &mtr); switch (err) { case DB_OVERFLOW: case DB_UNDERFLOW: case DB_ZIP_OVERFLOW: err = DB_FAIL; } } else { ut_a(mode == BTR_MODIFY_TREE); err = btr_cur_pessimistic_update( BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG, btr_cur, &heap, &dummy_big_rec, update, 0, thr, &mtr); ut_a(!dummy_big_rec); } mem_heap_free(heap); } btr_pcur_close(&pcur); mtr_commit(&mtr); return(err); } /***********************************************************//** Undoes a modify in secondary indexes when undo record type is UPD_DEL. @return DB_SUCCESS or DB_OUT_OF_FILE_SPACE */ static ulint row_undo_mod_upd_del_sec( /*=====================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr) /*!< in: query thread */ { mem_heap_t* heap; dtuple_t* entry; dict_index_t* index; ulint err = DB_SUCCESS; ut_ad(node->rec_type == TRX_UNDO_UPD_DEL_REC); heap = mem_heap_create(1024); while (node->index != NULL) { index = node->index; entry = row_build_index_entry(node->row, node->ext, index, heap); if (UNIV_UNLIKELY(!entry)) { /* The database must have crashed after inserting a clustered index record but before writing all the externally stored columns of that record. Because secondary index entries are inserted after the clustered index record, we may assume that the secondary index record does not exist. However, this situation may only occur during the rollback of incomplete transactions. */ ut_a(thr_is_recv(thr)); } else { err = row_undo_mod_del_mark_or_remove_sec( node, thr, index, entry); if (err != DB_SUCCESS) { break; } } mem_heap_empty(heap); node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); return(err); } /***********************************************************//** Undoes a modify in secondary indexes when undo record type is DEL_MARK. @return DB_SUCCESS or DB_OUT_OF_FILE_SPACE */ static ulint row_undo_mod_del_mark_sec( /*======================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr) /*!< in: query thread */ { mem_heap_t* heap; dtuple_t* entry; dict_index_t* index; ulint err; heap = mem_heap_create(1024); while (node->index != NULL) { index = node->index; entry = row_build_index_entry(node->row, node->ext, index, heap); ut_a(entry); err = row_undo_mod_del_unmark_sec_and_undo_update( BTR_MODIFY_LEAF, thr, index, entry); if (err == DB_FAIL) { err = row_undo_mod_del_unmark_sec_and_undo_update( BTR_MODIFY_TREE, thr, index, entry); } if (err != DB_SUCCESS) { mem_heap_free(heap); return(err); } node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); return(DB_SUCCESS); } /***********************************************************//** Undoes a modify in secondary indexes when undo record type is UPD_EXIST. @return DB_SUCCESS or DB_OUT_OF_FILE_SPACE */ static ulint row_undo_mod_upd_exist_sec( /*=======================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr) /*!< in: query thread */ { mem_heap_t* heap; dtuple_t* entry; dict_index_t* index; ulint err; if (node->cmpl_info & UPD_NODE_NO_ORD_CHANGE) { /* No change in secondary indexes */ return(DB_SUCCESS); } heap = mem_heap_create(1024); while (node->index != NULL) { index = node->index; if (row_upd_changes_ord_field_binary(node->row, node->index, node->update)) { /* Build the newest version of the index entry */ entry = row_build_index_entry(node->row, node->ext, index, heap); if (UNIV_UNLIKELY(!entry)) { /* The server must have crashed in row_upd_clust_rec_by_insert(), in row_ins_index_entry_low() before btr_store_big_rec_extern_fields() has written the externally stored columns (BLOBs) of the new clustered index entry. */ /* The table must be in DYNAMIC or COMPRESSED format. REDUNDANT and COMPACT formats store a local 768-byte prefix of each externally stored column. */ ut_a(dict_table_get_format(index->table) >= DICT_TF_FORMAT_ZIP); /* This is only legitimate when rolling back an incomplete transaction after crash recovery. */ ut_a(thr_get_trx(thr)->is_recovered); /* The server must have crashed before completing the insert of the new clustered index entry and before inserting to the secondary indexes. Because node->row was not yet written to this index, we can ignore it. But we must restore node->undo_row. */ } else { /* NOTE that if we updated the fields of a delete-marked secondary index record so that alphabetically they stayed the same, e.g., 'abc' -> 'aBc', we cannot return to the original values because we do not know them. But this should not cause problems because in row0sel.c, in queries we always retrieve the clustered index record or an earlier version of it, if the secondary index record through which we do the search is delete-marked. */ err = row_undo_mod_del_mark_or_remove_sec( node, thr, index, entry); if (err != DB_SUCCESS) { mem_heap_free(heap); return(err); } mem_heap_empty(heap); } /* We may have to update the delete mark in the secondary index record of the previous version of the row. We also need to update the fields of the secondary index record if we updated its fields but alphabetically they stayed the same, e.g., 'abc' -> 'aBc'. */ entry = row_build_index_entry(node->undo_row, node->undo_ext, index, heap); ut_a(entry); err = row_undo_mod_del_unmark_sec_and_undo_update( BTR_MODIFY_LEAF, thr, index, entry); if (err == DB_FAIL) { err = row_undo_mod_del_unmark_sec_and_undo_update( BTR_MODIFY_TREE, thr, index, entry); } if (err != DB_SUCCESS) { mem_heap_free(heap); return(err); } } node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); return(DB_SUCCESS); } /***********************************************************//** Parses the row reference and other info in a modify undo log record. */ static void row_undo_mod_parse_undo_rec( /*========================*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr) /*!< in: query thread */ { dict_index_t* clust_index; byte* ptr; undo_no_t undo_no; dulint table_id; trx_id_t trx_id; roll_ptr_t roll_ptr; ulint info_bits; ulint type; ulint cmpl_info; ibool dummy_extern; trx_t* trx; ut_ad(node && thr); trx = thr_get_trx(thr); ptr = trx_undo_rec_get_pars(node->undo_rec, &type, &cmpl_info, &dummy_extern, &undo_no, &table_id); node->rec_type = type; node->table = dict_table_get_on_id(table_id, trx); /* TODO: other fixes associated with DROP TABLE + rollback in the same table by another user */ if (node->table == NULL) { /* Table was dropped */ return; } if (node->table->ibd_file_missing) { /* We skip undo operations to missing .ibd files */ node->table = NULL; return; } clust_index = dict_table_get_first_index(node->table); ptr = trx_undo_update_rec_get_sys_cols(ptr, &trx_id, &roll_ptr, &info_bits); ptr = trx_undo_rec_get_row_ref(ptr, clust_index, &(node->ref), node->heap); trx_undo_update_rec_get_update(ptr, clust_index, type, trx_id, roll_ptr, info_bits, trx, node->heap, &(node->update)); node->new_roll_ptr = roll_ptr; node->new_trx_id = trx_id; node->cmpl_info = cmpl_info; } /***********************************************************//** Undoes a modify operation on a row of a table. @return DB_SUCCESS or error code */ UNIV_INTERN ulint row_undo_mod( /*=========*/ undo_node_t* node, /*!< in: row undo node */ que_thr_t* thr) /*!< in: query thread */ { ulint err; ut_ad(node && thr); ut_ad(node->state == UNDO_NODE_MODIFY); row_undo_mod_parse_undo_rec(node, thr); if (!node->table || !row_undo_search_clust_to_pcur(node)) { /* It is already undone, or will be undone by another query thread, or table was dropped */ trx_undo_rec_release(node->trx, node->undo_no); node->state = UNDO_NODE_FETCH_NEXT; return(DB_SUCCESS); } node->index = dict_table_get_next_index( dict_table_get_first_index(node->table)); if (node->rec_type == TRX_UNDO_UPD_EXIST_REC) { err = row_undo_mod_upd_exist_sec(node, thr); } else if (node->rec_type == TRX_UNDO_DEL_MARK_REC) { err = row_undo_mod_del_mark_sec(node, thr); } else { ut_ad(node->rec_type == TRX_UNDO_UPD_DEL_REC); err = row_undo_mod_upd_del_sec(node, thr); } if (err != DB_SUCCESS) { return(err); } err = row_undo_mod_clust(node, thr); return(err); }