/***************************************************************************** Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved. Copyright (c) 2017, 2021, MariaDB Corporation. 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA *****************************************************************************/ /**************************************************//** @file row/row0purge.cc Purge obsolete records Created 3/14/1997 Heikki Tuuri *******************************************************/ #include "row0purge.h" #include "btr0cur.h" #include "fsp0fsp.h" #include "mach0data.h" #include "dict0crea.h" #include "dict0stats.h" #include "trx0rseg.h" #include "trx0trx.h" #include "trx0roll.h" #include "trx0undo.h" #include "trx0purge.h" #include "trx0rec.h" #include "que0que.h" #include "row0row.h" #include "row0upd.h" #include "row0vers.h" #include "row0mysql.h" #include "row0log.h" #include "log0log.h" #include "srv0mon.h" #include "srv0start.h" #include "handler.h" #include "ha_innodb.h" #include "fil0fil.h" #include /************************************************************************* 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. */ /***********************************************************//** Repositions the pcur in the purge node on the clustered index record, if found. If the record is not found, close pcur. @return TRUE if the record was found */ static ibool row_purge_reposition_pcur( /*======================*/ ulint mode, /*!< in: latching mode */ purge_node_t* node, /*!< in: row purge node */ mtr_t* mtr) /*!< in: mtr */ { if (node->found_clust) { ut_ad(node->validate_pcur()); node->found_clust = node->pcur.restore_position(mode, mtr) == btr_pcur_t::SAME_ALL; } else { node->found_clust = row_search_on_row_ref( &node->pcur, mode, node->table, node->ref, mtr); if (node->found_clust) { btr_pcur_store_position(&node->pcur, mtr); } } /* Close the current cursor if we fail to position it correctly. */ if (!node->found_clust) { btr_pcur_close(&node->pcur); } return(node->found_clust); } /***********************************************************//** Removes a delete marked clustered index record if possible. @retval true if the row was not found, or it was successfully removed @retval false if the row was modified after the delete marking */ static MY_ATTRIBUTE((nonnull, warn_unused_result)) bool row_purge_remove_clust_if_poss_low( /*===============================*/ purge_node_t* node, /*!< in/out: row purge node */ ulint mode) /*!< in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */ { dict_index_t* index = dict_table_get_first_index(node->table); table_id_t table_id = 0; index_id_t index_id = 0; dict_table_t *table = nullptr; pfs_os_file_t f = OS_FILE_CLOSED; if (table_id) { retry: purge_sys.check_stop_FTS(); dict_sys.lock(SRW_LOCK_CALL); table = dict_sys.find_table(table_id); if (!table) { dict_sys.unlock(); } else if (table->n_rec_locks) { for (dict_index_t* ind = UT_LIST_GET_FIRST( table->indexes); ind; ind = UT_LIST_GET_NEXT(indexes, ind)) { if (ind->id == index_id) { lock_discard_for_index(*ind); } } } } mtr_t mtr; mtr.start(); index->set_modified(mtr); log_free_check(); bool success = true; if (!row_purge_reposition_pcur(mode, node, &mtr)) { /* The record was already removed. */ removed: mtr.commit(); close_and_exit: if (table) { dict_sys.unlock(); } return success; } if (node->table->id == DICT_INDEXES_ID) { /* If this is a record of the SYS_INDEXES table, then we have to free the file segments of the index tree associated with the index */ if (!table_id) { const rec_t* rec = btr_pcur_get_rec(&node->pcur); table_id = mach_read_from_8(rec); index_id = mach_read_from_8(rec + 8); if (table_id) { mtr.commit(); goto retry; } ut_ad("corrupted SYS_INDEXES record" == 0); } if (const uint32_t space_id = dict_drop_index_tree( &node->pcur, nullptr, &mtr)) { if (table) { if (table->get_ref_count() == 0) { dict_sys.remove(table); } else if (table->space_id == space_id) { table->space = nullptr; table->file_unreadable = true; } dict_sys.unlock(); table = nullptr; } f = fil_delete_tablespace(space_id); } mtr.commit(); if (table) { dict_sys.unlock(); table = nullptr; } purge_sys.check_stop_SYS(); mtr.start(); index->set_modified(mtr); if (!row_purge_reposition_pcur(mode, node, &mtr)) { goto removed; } } rec_t* rec = btr_pcur_get_rec(&node->pcur); rec_offs offsets_[REC_OFFS_NORMAL_SIZE]; rec_offs_init(offsets_); mem_heap_t* heap = NULL; rec_offs* offsets = rec_get_offsets(rec, index, offsets_, index->n_core_fields, ULINT_UNDEFINED, &heap); if (node->roll_ptr != row_get_rec_roll_ptr(rec, index, offsets)) { /* Someone else has modified the record later: do not remove */ goto func_exit; } ut_ad(rec_get_deleted_flag(rec, rec_offs_comp(offsets))); /* In delete-marked records, DB_TRX_ID must always refer to an existing undo log record. */ ut_ad(row_get_rec_trx_id(rec, index, offsets)); if (mode == BTR_MODIFY_LEAF) { success = btr_cur_optimistic_delete( btr_pcur_get_btr_cur(&node->pcur), 0, &mtr); } else { dberr_t err; ut_ad(mode == (BTR_MODIFY_TREE | BTR_LATCH_FOR_DELETE)); btr_cur_pessimistic_delete( &err, FALSE, btr_pcur_get_btr_cur(&node->pcur), 0, false, &mtr); switch (err) { case DB_SUCCESS: break; case DB_OUT_OF_FILE_SPACE: success = false; break; default: ut_error; } } func_exit: if (heap) { mem_heap_free(heap); } /* Persistent cursor is closed if reposition fails. */ if (node->found_clust) { btr_pcur_commit_specify_mtr(&node->pcur, &mtr); } else { mtr_commit(&mtr); } goto close_and_exit; } /***********************************************************//** Removes a clustered index record if it has not been modified after the delete marking. @retval true if the row was not found, or it was successfully removed @retval false the purge needs to be suspended because of running out of file space. */ static MY_ATTRIBUTE((nonnull, warn_unused_result)) bool row_purge_remove_clust_if_poss( /*===========================*/ purge_node_t* node) /*!< in/out: row purge node */ { if (row_purge_remove_clust_if_poss_low(node, BTR_MODIFY_LEAF)) { return(true); } for (ulint n_tries = 0; n_tries < BTR_CUR_RETRY_DELETE_N_TIMES; n_tries++) { if (row_purge_remove_clust_if_poss_low( node, BTR_MODIFY_TREE | BTR_LATCH_FOR_DELETE)) { return(true); } std::this_thread::sleep_for(BTR_CUR_RETRY_SLEEP_TIME); } return(false); } /** Determines if it is possible to remove a secondary index entry. Removal is possible if the secondary index entry does not refer to any not delete marked version of a clustered index record where DB_TRX_ID is newer than the purge view. NOTE: This function should only be called by the purge thread, only while holding a latch on the leaf page of the secondary index entry (or keeping the buffer pool watch on the page). It is possible that this function first returns true and then false, if a user transaction inserts a record that the secondary index entry would refer to. However, in that case, the user transaction would also re-insert the secondary index entry after purge has removed it and released the leaf page latch. @param[in,out] node row purge node @param[in] index secondary index @param[in] entry secondary index entry @param[in,out] sec_pcur secondary index cursor or NULL if it is called for purge buffering operation. @param[in,out] sec_mtr mini-transaction which holds secondary index entry or NULL if it is called for purge buffering operation. @param[in] is_tree true=pessimistic purge, false=optimistic (leaf-page only) @return true if the secondary index record can be purged */ bool row_purge_poss_sec( purge_node_t* node, dict_index_t* index, const dtuple_t* entry, btr_pcur_t* sec_pcur, mtr_t* sec_mtr, bool is_tree) { bool can_delete; mtr_t mtr; ut_ad(!dict_index_is_clust(index)); mtr_start(&mtr); can_delete = !row_purge_reposition_pcur(BTR_SEARCH_LEAF, node, &mtr) || !row_vers_old_has_index_entry(true, btr_pcur_get_rec(&node->pcur), &mtr, index, entry, node->roll_ptr, node->trx_id); /* Persistent cursor is closed if reposition fails. */ if (node->found_clust) { btr_pcur_commit_specify_mtr(&node->pcur, &mtr); } else { mtr.commit(); } ut_ad(mtr.has_committed()); return can_delete; } /*************************************************************** Removes a secondary index entry if possible, by modifying the index tree. Does not try to buffer the delete. @return TRUE if success or if not found */ static MY_ATTRIBUTE((nonnull, warn_unused_result)) ibool row_purge_remove_sec_if_poss_tree( /*==============================*/ purge_node_t* node, /*!< in: row purge node */ dict_index_t* index, /*!< in: index */ const dtuple_t* entry) /*!< in: index entry */ { btr_pcur_t pcur; ibool success = TRUE; dberr_t err; mtr_t mtr; enum row_search_result search_result; log_free_check(); mtr.start(); index->set_modified(mtr); if (!index->is_committed()) { /* The index->online_status may change if the index is or was being created online, but not committed yet. It is protected by index->lock. */ mtr_sx_lock_index(index, &mtr); if (dict_index_is_online_ddl(index)) { /* Online secondary index creation will not copy any delete-marked records. Therefore there is nothing to be purged. We must also skip the purge when a completed index is dropped by rollback_inplace_alter_table(). */ goto func_exit_no_pcur; } } else { /* For secondary indexes, index->online_status==ONLINE_INDEX_COMPLETE if index->is_committed(). */ ut_ad(!dict_index_is_online_ddl(index)); } search_result = row_search_index_entry( index, entry, BTR_MODIFY_TREE | BTR_LATCH_FOR_DELETE, &pcur, &mtr); switch (search_result) { case ROW_NOT_FOUND: /* Not found. This is a legitimate condition. In a rollback, InnoDB will remove secondary recs that would be purged anyway. Then the actual purge will not find the secondary index record. Also, the purge itself is eager: if it comes to consider a secondary index record, and notices it does not need to exist in the index, it will remove it. Then if/when the purge comes to consider the secondary index record a second time, it will not exist any more in the index. */ /* fputs("PURGE:........sec entry not found\n", stderr); */ /* dtuple_print(stderr, entry); */ goto func_exit; case ROW_FOUND: break; case ROW_BUFFERED: case ROW_NOT_DELETED_REF: /* These are invalid outcomes, because the mode passed to row_search_index_entry() did not include any of the flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */ ut_error; } /* We should remove the index record if no later version of the row, which cannot be purged yet, requires its existence. If some requires, we should do nothing. */ if (row_purge_poss_sec(node, index, entry, &pcur, &mtr, true)) { /* Remove the index record, which should have been marked for deletion. */ if (!rec_get_deleted_flag(btr_cur_get_rec( btr_pcur_get_btr_cur(&pcur)), dict_table_is_comp(index->table))) { ib::error() << "tried to purge non-delete-marked record" " in index " << index->name << " of table " << index->table->name << ": tuple: " << *entry << ", record: " << rec_index_print( btr_cur_get_rec( btr_pcur_get_btr_cur(&pcur)), index); ut_ad(0); goto func_exit; } btr_cur_pessimistic_delete(&err, FALSE, btr_pcur_get_btr_cur(&pcur), 0, false, &mtr); switch (UNIV_EXPECT(err, DB_SUCCESS)) { case DB_SUCCESS: break; case DB_OUT_OF_FILE_SPACE: success = FALSE; break; default: ut_error; } } func_exit: btr_pcur_close(&pcur); // FIXME: need this? func_exit_no_pcur: mtr.commit(); return(success); } /*************************************************************** Removes a secondary index entry without modifying the index tree, if possible. @retval true if success or if not found @retval false if row_purge_remove_sec_if_poss_tree() should be invoked */ static MY_ATTRIBUTE((nonnull, warn_unused_result)) bool row_purge_remove_sec_if_poss_leaf( /*==============================*/ purge_node_t* node, /*!< in: row purge node */ dict_index_t* index, /*!< in: index */ const dtuple_t* entry) /*!< in: index entry */ { mtr_t mtr; btr_pcur_t pcur; enum btr_latch_mode mode; enum row_search_result search_result; bool success = true; log_free_check(); ut_ad(index->table == node->table); ut_ad(!index->table->is_temporary()); mtr.start(); index->set_modified(mtr); if (!index->is_committed()) { /* For uncommitted spatial index, we also skip the purge. */ if (dict_index_is_spatial(index)) { goto func_exit_no_pcur; } /* The index->online_status may change if the the index is or was being created online, but not committed yet. It is protected by index->lock. */ mtr_s_lock_index(index, &mtr); if (dict_index_is_online_ddl(index)) { /* Online secondary index creation will not copy any delete-marked records. Therefore there is nothing to be purged. We must also skip the purge when a completed index is dropped by rollback_inplace_alter_table(). */ goto func_exit_no_pcur; } mode = BTR_PURGE_LEAF_ALREADY_S_LATCHED; } else { /* For secondary indexes, index->online_status==ONLINE_INDEX_COMPLETE if index->is_committed(). */ ut_ad(!dict_index_is_online_ddl(index)); /* Change buffering is disabled for spatial index and virtual index. */ mode = (dict_index_is_spatial(index) || dict_index_has_virtual(index)) ? BTR_MODIFY_LEAF : BTR_PURGE_LEAF; } /* Set the purge node for the call to row_purge_poss_sec(). */ pcur.btr_cur.purge_node = node; if (index->is_spatial()) { pcur.btr_cur.thr = NULL; index->lock.u_lock(SRW_LOCK_CALL); search_result = row_search_index_entry( index, entry, mode, &pcur, &mtr); index->lock.u_unlock(); } else { /* Set the query thread, so that ibuf_insert_low() will be able to invoke thd_get_trx(). */ pcur.btr_cur.thr = static_cast( que_node_get_parent(node)); search_result = row_search_index_entry( index, entry, mode, &pcur, &mtr); } switch (search_result) { case ROW_FOUND: /* Before attempting to purge a record, check if it is safe to do so. */ if (row_purge_poss_sec(node, index, entry, &pcur, &mtr, false)) { btr_cur_t* btr_cur = btr_pcur_get_btr_cur(&pcur); /* Only delete-marked records should be purged. */ if (!rec_get_deleted_flag( btr_cur_get_rec(btr_cur), dict_table_is_comp(index->table))) { ib::error() << "tried to purge non-delete-marked" " record" " in index " << index->name << " of table " << index->table->name << ": tuple: " << *entry << ", record: " << rec_index_print( btr_cur_get_rec(btr_cur), index); ut_ad(0); btr_pcur_close(&pcur); goto func_exit_no_pcur; } if (index->is_spatial()) { const buf_block_t* block = btr_cur_get_block( btr_cur); if (block->page.id().page_no() != index->page && page_get_n_recs(block->page.frame) < 2 && !lock_test_prdt_page_lock( btr_cur->rtr_info && btr_cur->rtr_info->thr ? thr_get_trx( btr_cur->rtr_info->thr) : nullptr, block->page.id())) { /* this is the last record on page, and it has a "page" lock on it, which mean search is still depending on it, so do not delete */ DBUG_LOG("purge", "skip purging last" " record on page " << block->page.id()); btr_pcur_close(&pcur); mtr.commit(); return(success); } } if (!btr_cur_optimistic_delete(btr_cur, 0, &mtr)) { /* The index entry could not be deleted. */ success = false; } } /* (The index entry is still needed, or the deletion succeeded) */ /* fall through */ case ROW_NOT_DELETED_REF: /* The index entry is still needed. */ case ROW_BUFFERED: /* The deletion was buffered. */ case ROW_NOT_FOUND: /* The index entry does not exist, nothing to do. */ btr_pcur_close(&pcur); // FIXME: do we need these? when is btr_cur->rtr_info set? func_exit_no_pcur: mtr.commit(); return(success); } ut_error; return(false); } /***********************************************************//** Removes a secondary index entry if possible. */ UNIV_INLINE MY_ATTRIBUTE((nonnull(1,2))) void row_purge_remove_sec_if_poss( /*=========================*/ purge_node_t* node, /*!< in: row purge node */ dict_index_t* index, /*!< in: index */ const dtuple_t* entry) /*!< in: index entry */ { ibool success; ulint n_tries = 0; /* fputs("Purge: Removing secondary record\n", stderr); */ if (!entry) { /* The node->row must have lacked some fields of this index. This is possible when the undo log record was written before this index was created. */ return; } if (row_purge_remove_sec_if_poss_leaf(node, index, entry)) { return; } retry: success = row_purge_remove_sec_if_poss_tree(node, index, entry); /* The delete operation may fail if we have little file space left: TODO: easiest to crash the database and restart with more file space */ if (!success && n_tries < BTR_CUR_RETRY_DELETE_N_TIMES) { n_tries++; std::this_thread::sleep_for(BTR_CUR_RETRY_SLEEP_TIME); goto retry; } ut_a(success); } /** Skip uncommitted virtual indexes on newly added virtual column. @param[in,out] index dict index object */ static inline void row_purge_skip_uncommitted_virtual_index( dict_index_t*& index) { /* We need to skip virtual indexes which is not committed yet. It's safe because these indexes are newly created by alter table, and because we do not support LOCK=NONE when adding an index on newly added virtual column.*/ while (index != NULL && dict_index_has_virtual(index) && !index->is_committed() && index->has_new_v_col()) { index = dict_table_get_next_index(index); } } /***********************************************************//** Purges a delete marking of a record. @retval true if the row was not found, or it was successfully removed @retval false the purge needs to be suspended because of running out of file space */ static MY_ATTRIBUTE((nonnull, warn_unused_result)) bool row_purge_del_mark( /*===============*/ purge_node_t* node) /*!< in/out: row purge node */ { mem_heap_t* heap; heap = mem_heap_create(1024); while (node->index != NULL) { /* skip corrupted secondary index */ dict_table_skip_corrupt_index(node->index); row_purge_skip_uncommitted_virtual_index(node->index); if (!node->index) { break; } if (node->index->type != DICT_FTS) { dtuple_t* entry = row_build_index_entry_low( node->row, NULL, node->index, heap, ROW_BUILD_FOR_PURGE); row_purge_remove_sec_if_poss(node, node->index, entry); mem_heap_empty(heap); } node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); return(row_purge_remove_clust_if_poss(node)); } void purge_sys_t::wait_SYS() { while (must_wait_SYS()) std::this_thread::sleep_for(std::chrono::seconds(1)); } void purge_sys_t::wait_FTS() { while (must_wait_FTS()) std::this_thread::sleep_for(std::chrono::seconds(1)); } /** Reset DB_TRX_ID, DB_ROLL_PTR of a clustered index record whose old history can no longer be observed. @param[in,out] node purge node @param[in,out] mtr mini-transaction (will be started and committed) */ static void row_purge_reset_trx_id(purge_node_t* node, mtr_t* mtr) { retry: /* Reset DB_TRX_ID, DB_ROLL_PTR for old records. */ mtr->start(); if (row_purge_reposition_pcur(BTR_MODIFY_LEAF, node, mtr)) { dict_index_t* index = dict_table_get_first_index( node->table); ulint trx_id_pos = index->n_uniq ? index->n_uniq : 1; rec_t* rec = btr_pcur_get_rec(&node->pcur); mem_heap_t* heap = NULL; /* Reserve enough offsets for the PRIMARY KEY and 2 columns so that we can access DB_TRX_ID, DB_ROLL_PTR. */ rec_offs offsets_[REC_OFFS_HEADER_SIZE + MAX_REF_PARTS + 2]; rec_offs_init(offsets_); rec_offs* offsets = rec_get_offsets( rec, index, offsets_, index->n_core_fields, trx_id_pos + 2, &heap); ut_ad(heap == NULL); ut_ad(dict_index_get_nth_field(index, trx_id_pos) ->col->mtype == DATA_SYS); ut_ad(dict_index_get_nth_field(index, trx_id_pos) ->col->prtype == (DATA_TRX_ID | DATA_NOT_NULL)); ut_ad(dict_index_get_nth_field(index, trx_id_pos + 1) ->col->mtype == DATA_SYS); ut_ad(dict_index_get_nth_field(index, trx_id_pos + 1) ->col->prtype == (DATA_ROLL_PTR | DATA_NOT_NULL)); /* Only update the record if DB_ROLL_PTR matches (the record has not been modified after this transaction became purgeable) */ if (node->roll_ptr == row_get_rec_roll_ptr(rec, index, offsets)) { ut_ad(!rec_get_deleted_flag( rec, rec_offs_comp(offsets)) || rec_is_alter_metadata(rec, *index)); switch (node->table->id) { case DICT_TABLES_ID: case DICT_COLUMNS_ID: case DICT_INDEXES_ID: if (purge_sys.must_wait_SYS()) { mtr->commit(); purge_sys.check_stop_SYS(); goto retry; } } DBUG_LOG("purge", "reset DB_TRX_ID=" << ib::hex(row_get_rec_trx_id( rec, index, offsets))); index->set_modified(*mtr); buf_block_t* block = btr_pcur_get_block(&node->pcur); if (UNIV_LIKELY_NULL(block->page.zip.data)) { page_zip_write_trx_id_and_roll_ptr( block, rec, offsets, trx_id_pos, 0, 1ULL << ROLL_PTR_INSERT_FLAG_POS, mtr); } else { ulint len; byte* ptr = rec_get_nth_field( rec, offsets, trx_id_pos, &len); ut_ad(len == DATA_TRX_ID_LEN); size_t offs = page_offset(ptr); mtr->memset(block, offs, DATA_TRX_ID_LEN, 0); offs += DATA_TRX_ID_LEN; mtr->write<1,mtr_t::MAYBE_NOP>( *block, block->page.frame + offs, 0x80U); mtr->memset(block, offs + 1, DATA_ROLL_PTR_LEN - 1, 0); } } } mtr->commit(); } /***********************************************************//** Purges an update of an existing record. Also purges an update of a delete marked record if that record contained an externally stored field. */ static void row_purge_upd_exist_or_extern_func( /*===============================*/ #ifdef UNIV_DEBUG const que_thr_t*thr, /*!< in: query thread */ #endif /* UNIV_DEBUG */ purge_node_t* node, /*!< in: row purge node */ trx_undo_rec_t* undo_rec) /*!< in: record to purge */ { mem_heap_t* heap; ut_ad(!node->table->skip_alter_undo); if (node->rec_type == TRX_UNDO_UPD_DEL_REC || (node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)) { goto skip_secondaries; } heap = mem_heap_create(1024); while (node->index != NULL) { dict_table_skip_corrupt_index(node->index); row_purge_skip_uncommitted_virtual_index(node->index); if (!node->index) { break; } if (row_upd_changes_ord_field_binary(node->index, node->update, thr, NULL, NULL)) { /* Build the older version of the index entry */ dtuple_t* entry = row_build_index_entry_low( node->row, NULL, node->index, heap, ROW_BUILD_FOR_PURGE); row_purge_remove_sec_if_poss(node, node->index, entry); ut_ad(node->table); mem_heap_empty(heap); } node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); skip_secondaries: mtr_t mtr; dict_index_t* index = dict_table_get_first_index(node->table); /* Free possible externally stored fields */ for (ulint i = 0; i < upd_get_n_fields(node->update); i++) { const upd_field_t* ufield = upd_get_nth_field(node->update, i); if (dfield_is_ext(&ufield->new_val)) { buf_block_t* block; byte* data_field; bool is_insert; ulint rseg_id; uint32_t page_no; uint16_t offset; /* We use the fact that new_val points to undo_rec and get thus the offset of dfield data inside the undo record. Then we can calculate from node->roll_ptr the file address of the new_val data */ const uint16_t internal_offset = uint16_t( static_cast (dfield_get_data(&ufield->new_val)) - undo_rec); ut_a(internal_offset < srv_page_size); trx_undo_decode_roll_ptr(node->roll_ptr, &is_insert, &rseg_id, &page_no, &offset); const trx_rseg_t &rseg = trx_sys.rseg_array[rseg_id]; ut_ad(rseg.is_persistent()); mtr.start(); /* We have to acquire an SX-latch to the clustered index tree (exclude other tree changes) */ mtr_sx_lock_index(index, &mtr); index->set_modified(mtr); /* NOTE: we must also acquire a U latch to the root page of the tree. We will need it when we free pages from the tree. If the tree is of height 1, the tree X-latch does NOT protect the root page, because it is also a leaf page. Since we will have a latch on an undo log page, we would break the latching order if we would only later latch the root page of such a tree! */ btr_root_block_get(index, RW_SX_LATCH, &mtr); block = buf_page_get( page_id_t(rseg.space->id, page_no), 0, RW_X_LATCH, &mtr); data_field = buf_block_get_frame(block) + offset + internal_offset; ut_a(dfield_get_len(&ufield->new_val) >= BTR_EXTERN_FIELD_REF_SIZE); btr_free_externally_stored_field( index, data_field + dfield_get_len(&ufield->new_val) - BTR_EXTERN_FIELD_REF_SIZE, NULL, NULL, block, 0, false, &mtr); mtr.commit(); } } row_purge_reset_trx_id(node, &mtr); } #ifdef UNIV_DEBUG # define row_purge_upd_exist_or_extern(thr,node,undo_rec) \ row_purge_upd_exist_or_extern_func(thr,node,undo_rec) #else /* UNIV_DEBUG */ # define row_purge_upd_exist_or_extern(thr,node,undo_rec) \ row_purge_upd_exist_or_extern_func(node,undo_rec) #endif /* UNIV_DEBUG */ /** Parses the row reference and other info in a modify undo log record. @param[in] node row undo node @param[in] undo_rec record to purge @param[in] thr query thread @param[out] updated_extern true if an externally stored field was updated @return true if purge operation required */ static bool row_purge_parse_undo_rec( purge_node_t* node, trx_undo_rec_t* undo_rec, que_thr_t* thr, bool* updated_extern) { dict_index_t* clust_index; byte* ptr; undo_no_t undo_no; table_id_t table_id; roll_ptr_t roll_ptr; byte info_bits; ulint type; ut_ad(node != NULL); ut_ad(thr != NULL); ptr = trx_undo_rec_get_pars( undo_rec, &type, &node->cmpl_info, updated_extern, &undo_no, &table_id); node->rec_type = type; switch (type) { case TRX_UNDO_RENAME_TABLE: return false; case TRX_UNDO_EMPTY: case TRX_UNDO_INSERT_METADATA: case TRX_UNDO_INSERT_REC: /* These records do not store any transaction identifier. FIXME: Update SYS_TABLES.ID on both DISCARD TABLESPACE and IMPORT TABLESPACE to get rid of the repeated lookups! */ node->trx_id = TRX_ID_MAX; break; default: #ifdef UNIV_DEBUG ut_ad("unknown undo log record type" == 0); return false; case TRX_UNDO_UPD_DEL_REC: case TRX_UNDO_UPD_EXIST_REC: case TRX_UNDO_DEL_MARK_REC: #endif /* UNIV_DEBUG */ ptr = trx_undo_update_rec_get_sys_cols(ptr, &node->trx_id, &roll_ptr, &info_bits); break; } if (node->is_skipped(table_id)) { return false; } trx_id_t trx_id = TRX_ID_MAX; if (node->retain_mdl(table_id)) { ut_ad(node->table != NULL); goto already_locked; } try_again: purge_sys.check_stop_FTS(); node->table = dict_table_open_on_id( table_id, false, DICT_TABLE_OP_NORMAL, node->purge_thd, &node->mdl_ticket); if (!node->table) { /* The table has been dropped: no need to do purge and release mdl happened as a part of open process itself */ goto err_exit; } already_locked: ut_ad(!node->table->is_temporary()); switch (type) { case TRX_UNDO_INSERT_METADATA: case TRX_UNDO_INSERT_REC: break; default: if (!node->table->n_v_cols || node->table->vc_templ || !dict_table_has_indexed_v_cols(node->table)) { break; } /* Need server fully up for virtual column computation */ if (!mysqld_server_started) { node->close_table(); if (srv_shutdown_state > SRV_SHUTDOWN_NONE) { return(false); } std::this_thread::sleep_for(std::chrono::seconds(1)); goto try_again; } } clust_index = dict_table_get_first_index(node->table); if (!clust_index || clust_index->is_corrupted()) { /* The table was corrupt in the data dictionary. dict_set_corrupted() works on an index, and we do not have an index to call it with. */ DBUG_ASSERT(table_id == node->table->id); trx_id = node->table->def_trx_id; if (!trx_id) { trx_id = TRX_ID_MAX; } err_exit: node->close_table(); node->skip(table_id, trx_id); return(false); } node->last_table_id = table_id; if (type == TRX_UNDO_INSERT_METADATA) { node->ref = &trx_undo_metadata; return(true); } else if (type == TRX_UNDO_EMPTY) { node->ref = nullptr; return true; } ptr = trx_undo_rec_get_row_ref(ptr, clust_index, &(node->ref), node->heap); if (type == TRX_UNDO_INSERT_REC) { return(true); } ptr = trx_undo_update_rec_get_update(ptr, clust_index, type, node->trx_id, roll_ptr, info_bits, node->heap, &(node->update)); /* Read to the partial row the fields that occur in indexes */ if (!(node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)) { ut_ad(!(node->update->info_bits & REC_INFO_MIN_REC_FLAG)); ptr = trx_undo_rec_get_partial_row( ptr, clust_index, node->update, &node->row, type == TRX_UNDO_UPD_DEL_REC, node->heap); } else if (node->update->info_bits & REC_INFO_MIN_REC_FLAG) { node->ref = &trx_undo_metadata; } return(true); } /** Purges the parsed record. @param[in] node row purge node @param[in] undo_rec record to purge @param[in] thr query thread @param[in] updated_extern whether external columns were updated @return true if purged, false if skipped */ static MY_ATTRIBUTE((nonnull, warn_unused_result)) bool row_purge_record_func( purge_node_t* node, trx_undo_rec_t* undo_rec, #if defined UNIV_DEBUG || defined WITH_WSREP const que_thr_t*thr, #endif /* UNIV_DEBUG || WITH_WSREP */ bool updated_extern) { dict_index_t* clust_index; bool purged = true; ut_ad(!node->found_clust); ut_ad(!node->table->skip_alter_undo); clust_index = dict_table_get_first_index(node->table); node->index = dict_table_get_next_index(clust_index); ut_ad(!trx_undo_roll_ptr_is_insert(node->roll_ptr)); switch (node->rec_type) { case TRX_UNDO_EMPTY: break; case TRX_UNDO_DEL_MARK_REC: purged = row_purge_del_mark(node); if (purged) { if (node->table->stat_initialized && srv_stats_include_delete_marked) { dict_stats_update_if_needed( node->table, *thr->graph->trx); } MONITOR_INC(MONITOR_N_DEL_ROW_PURGE); } break; case TRX_UNDO_INSERT_METADATA: case TRX_UNDO_INSERT_REC: node->roll_ptr |= 1ULL << ROLL_PTR_INSERT_FLAG_POS; /* fall through */ default: if (!updated_extern) { mtr_t mtr; row_purge_reset_trx_id(node, &mtr); break; } /* fall through */ case TRX_UNDO_UPD_EXIST_REC: row_purge_upd_exist_or_extern(thr, node, undo_rec); MONITOR_INC(MONITOR_N_UPD_EXIST_EXTERN); break; } if (node->found_clust) { btr_pcur_close(&node->pcur); node->found_clust = FALSE; } return(purged); } #if defined UNIV_DEBUG || defined WITH_WSREP # define row_purge_record(node,undo_rec,thr,updated_extern) \ row_purge_record_func(node,undo_rec,thr,updated_extern) #else /* UNIV_DEBUG || WITH_WSREP */ # define row_purge_record(node,undo_rec,thr,updated_extern) \ row_purge_record_func(node,undo_rec,updated_extern) #endif /* UNIV_DEBUG || WITH_WSREP */ /***********************************************************//** Fetches an undo log record and does the purge for the recorded operation. If none left, or the current purge completed, returns the control to the parent node, which is always a query thread node. */ static MY_ATTRIBUTE((nonnull)) void row_purge( /*======*/ purge_node_t* node, /*!< in: row purge node */ trx_undo_rec_t* undo_rec, /*!< in: record to purge */ que_thr_t* thr) /*!< in: query thread */ { if (undo_rec != &trx_purge_dummy_rec) { bool updated_extern; while (row_purge_parse_undo_rec( node, undo_rec, thr, &updated_extern)) { bool purged = row_purge_record( node, undo_rec, thr, updated_extern); if (purged || srv_shutdown_state > SRV_SHUTDOWN_INITIATED) { return; } /* Retry the purge in a second. */ std::this_thread::sleep_for(std::chrono::seconds(1)); } } } /***********************************************************//** Reset the purge query thread. */ UNIV_INLINE void row_purge_end( /*==========*/ que_thr_t* thr) /*!< in: query thread */ { ut_ad(thr); thr->run_node = static_cast(thr->run_node)->end(); ut_a(thr->run_node != NULL); } /***********************************************************//** Does the purge operation for a single undo log record. This is a high-level function used in an SQL execution graph. @return query thread to run next or NULL */ que_thr_t* row_purge_step( /*===========*/ que_thr_t* thr) /*!< in: query thread */ { purge_node_t* node; node = static_cast(thr->run_node); node->start(); if (!node->undo_recs.empty()) { trx_purge_rec_t purge_rec = node->undo_recs.front(); node->undo_recs.pop(); node->roll_ptr = purge_rec.roll_ptr; row_purge(node, purge_rec.undo_rec, thr); if (node->undo_recs.empty()) { row_purge_end(thr); } else { thr->run_node = node; } } else { row_purge_end(thr); } return(thr); } #ifdef UNIV_DEBUG /***********************************************************//** Validate the persisent cursor. The purge node has two references to the clustered index record - one via the ref member, and the other via the persistent cursor. These two references must match each other if the found_clust flag is set. @return true if the stored copy of persistent cursor is consistent with the ref member.*/ bool purge_node_t::validate_pcur() { if (!found_clust) { return(true); } if (index == NULL) { return(true); } if (index->type == DICT_FTS) { return(true); } if (!pcur.old_stored) { return(true); } dict_index_t* clust_index = pcur.btr_cur.index; rec_offs* offsets = rec_get_offsets( pcur.old_rec, clust_index, NULL, pcur.old_n_core_fields, pcur.old_n_fields, &heap); /* Here we are comparing the purge ref record and the stored initial part in persistent cursor. Both cases we store n_uniq fields of the cluster index and so it is fine to do the comparison. We note this dependency here as pcur and ref belong to different modules. */ int st = cmp_dtuple_rec(ref, pcur.old_rec, offsets); if (st != 0) { ib::error() << "Purge node pcur validation failed"; ib::error() << rec_printer(ref).str(); ib::error() << rec_printer(pcur.old_rec, offsets).str(); return(false); } return(true); } #endif /* UNIV_DEBUG */