/****************************************************** Purge obsolete records (c) 1997 Innobase Oy Created 3/14/1997 Heikki Tuuri *******************************************************/ #include "row0purge.h" #ifdef UNIV_NONINL #include "row0purge.ic" #endif #include "fsp0fsp.h" #include "mach0data.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 "log0log.h" /************************************************************************ Creates a purge node to a query graph. */ purge_node_t* row_purge_node_create( /*==================*/ /* out, own: purge node */ que_thr_t* parent, /* in: parent node, i.e., a thr node */ mem_heap_t* heap) /* in: memory heap where created */ { purge_node_t* node; ut_ad(parent && heap); node = mem_heap_alloc(heap, sizeof(purge_node_t)); node->common.type = QUE_NODE_PURGE; node->common.parent = parent; node->heap = mem_heap_create(256); return(node); } /*************************************************************** Repositions the pcur in the purge node on the clustered index record, if found. */ static ibool row_purge_reposition_pcur( /*======================*/ /* out: TRUE if the record was found */ ulint mode, /* in: latching mode */ purge_node_t* node, /* in: row purge node */ mtr_t* mtr) /* in: mtr */ { ibool found; if (node->found_clust) { found = btr_pcur_restore_position(mode, &(node->pcur), mtr); return(found); } found = row_search_on_row_ref(&(node->pcur), mode, node->table, node->ref, mtr); node->found_clust = found; if (found) { btr_pcur_store_position(&(node->pcur), mtr); } return(found); } /*************************************************************** Removes a delete marked clustered index record if possible. */ static ibool row_purge_remove_clust_if_poss_low( /*===============================*/ /* out: TRUE if success, or if not found, or if modified after the delete marking */ purge_node_t* node, /* in: row purge node */ que_thr_t* thr, /* in: query thread */ ulint mode) /* in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */ { dict_index_t* index; btr_pcur_t* pcur; btr_cur_t* btr_cur; ibool success; ulint err; mtr_t mtr; UT_NOT_USED(thr); index = dict_table_get_first_index(node->table); pcur = &(node->pcur); btr_cur = btr_pcur_get_btr_cur(pcur); mtr_start(&mtr); success = row_purge_reposition_pcur(mode, node, &mtr); if (!success) { /* The record is already removed */ btr_pcur_commit_specify_mtr(pcur, &mtr); return(TRUE); } if (0 != ut_dulint_cmp(node->roll_ptr, row_get_rec_roll_ptr(btr_pcur_get_rec(pcur), index))) { /* Someone else has modified the record later: do not remove */ btr_pcur_commit_specify_mtr(pcur, &mtr); return(TRUE); } if (mode == BTR_MODIFY_LEAF) { success = btr_cur_optimistic_delete(btr_cur, &mtr); } else { ut_ad(mode == BTR_MODIFY_TREE); btr_cur_pessimistic_delete(&err, FALSE, btr_cur, FALSE, &mtr); if (err == DB_SUCCESS) { success = TRUE; } else if (err == DB_OUT_OF_FILE_SPACE) { success = FALSE; } else { ut_a(0); } } btr_pcur_commit_specify_mtr(pcur, &mtr); return(success); } /*************************************************************** Removes a clustered index record if it has not been modified after the delete marking. */ static void row_purge_remove_clust_if_poss( /*===========================*/ purge_node_t* node, /* in: row purge node */ que_thr_t* thr) /* in: query thread */ { ibool success; ulint n_tries = 0; /* printf("Purge: Removing clustered record\n"); */ success = row_purge_remove_clust_if_poss_low(node, thr, BTR_MODIFY_LEAF); if (success) { return; } retry: success = row_purge_remove_clust_if_poss_low(node, thr, BTR_MODIFY_TREE); /* 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++; os_thread_sleep(BTR_CUR_RETRY_SLEEP_TIME); goto retry; } ut_a(success); } /*************************************************************** Removes a secondary index entry if possible. */ static ibool row_purge_remove_sec_if_poss_low( /*=============================*/ /* out: TRUE if success or if not found */ purge_node_t* node, /* in: row purge 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 */ { btr_pcur_t pcur; btr_cur_t* btr_cur; ibool success; ibool old_has = 0; /* remove warning */ ibool found; ulint err; mtr_t mtr; mtr_t* mtr_vers; UT_NOT_USED(thr); log_free_check(); mtr_start(&mtr); found = row_search_index_entry(index, entry, mode, &pcur, &mtr); if (!found) { /* Not found */ /* printf("PURGE:........sec entry not found\n"); */ /* dtuple_print(entry); */ btr_pcur_close(&pcur); mtr_commit(&mtr); return(TRUE); } btr_cur = btr_pcur_get_btr_cur(&pcur); /* 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. */ mtr_vers = mem_alloc(sizeof(mtr_t)); mtr_start(mtr_vers); success = row_purge_reposition_pcur(BTR_SEARCH_LEAF, node, mtr_vers); if (success) { old_has = row_vers_old_has_index_entry(TRUE, btr_pcur_get_rec(&(node->pcur)), mtr_vers, index, entry); } btr_pcur_commit_specify_mtr(&(node->pcur), mtr_vers); mem_free(mtr_vers); if (!success || !old_has) { /* Remove the index record */ if (mode == BTR_MODIFY_LEAF) { success = btr_cur_optimistic_delete(btr_cur, &mtr); } else { ut_ad(mode == BTR_MODIFY_TREE); btr_cur_pessimistic_delete(&err, FALSE, btr_cur, FALSE, &mtr); if (err == DB_SUCCESS) { success = TRUE; } else if (err == DB_OUT_OF_FILE_SPACE) { success = FALSE; } else { ut_a(0); } } } btr_pcur_close(&pcur); mtr_commit(&mtr); return(success); } /*************************************************************** Removes a secondary index entry if possible. */ UNIV_INLINE void row_purge_remove_sec_if_poss( /*=========================*/ purge_node_t* node, /* in: row purge node */ que_thr_t* thr, /* in: query thread */ dict_index_t* index, /* in: index */ dtuple_t* entry) /* in: index entry */ { ibool success; ulint n_tries = 0; /* printf("Purge: Removing secondary record\n"); */ success = row_purge_remove_sec_if_poss_low(node, thr, index, entry, BTR_MODIFY_LEAF); if (success) { return; } retry: success = row_purge_remove_sec_if_poss_low(node, thr, index, entry, BTR_MODIFY_TREE); /* 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++; os_thread_sleep(BTR_CUR_RETRY_SLEEP_TIME); goto retry; } ut_a(success); } /*************************************************************** Purges a delete marking of a record. */ static void row_purge_del_mark( /*===============*/ purge_node_t* node, /* in: row purge node */ que_thr_t* thr) /* in: query thread */ { mem_heap_t* heap; dtuple_t* entry; dict_index_t* index; ut_ad(node && thr); heap = mem_heap_create(1024); while (node->index != NULL) { index = node->index; /* Build the index entry */ entry = row_build_index_entry(node->row, index, heap); row_purge_remove_sec_if_poss(node, thr, index, entry); node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); row_purge_remove_clust_if_poss(node, thr); } /*************************************************************** 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( /*==========================*/ purge_node_t* node, /* in: row purge node */ que_thr_t* thr) /* in: query thread */ { mem_heap_t* heap; dtuple_t* entry; dict_index_t* index; upd_field_t* ufield; ibool is_insert; ulint rseg_id; ulint page_no; ulint offset; ulint internal_offset; byte* data_field; ulint data_field_len; ulint i; mtr_t mtr; ut_ad(node && thr); if (node->rec_type == TRX_UNDO_UPD_DEL_REC) { goto skip_secondaries; } heap = mem_heap_create(1024); while (node->index != NULL) { index = node->index; if (row_upd_changes_ord_field_binary(NULL, node->index, node->update)) { /* Build the older version of the index entry */ entry = row_build_index_entry(node->row, index, heap); row_purge_remove_sec_if_poss(node, thr, index, entry); } node->index = dict_table_get_next_index(node->index); } mem_heap_free(heap); skip_secondaries: /* Free possible externally stored fields */ for (i = 0; i < upd_get_n_fields(node->update); i++) { ufield = upd_get_nth_field(node->update, i); if (ufield->extern_storage) { /* We use the fact that new_val points to node->undo_rec and get thus the offset of dfield data inside the unod record. Then we can calculate from node->roll_ptr the file address of the new_val data */ internal_offset = ((byte*)ufield->new_val.data) - node->undo_rec; ut_a(internal_offset < UNIV_PAGE_SIZE); trx_undo_decode_roll_ptr(node->roll_ptr, &is_insert, &rseg_id, &page_no, &offset); mtr_start(&mtr); /* We have to acquire an X-latch to the clustered index tree */ index = dict_table_get_first_index(node->table); mtr_x_lock(dict_tree_get_lock(index->tree), &mtr); /* NOTE: we must also acquire an X-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_get(index->tree, &mtr); /* We assume in purge of externally stored fields that the space id of the undo log record is 0! */ data_field = buf_page_get(0, page_no, RW_X_LATCH, &mtr) + offset + internal_offset; buf_page_dbg_add_level(buf_frame_align(data_field), SYNC_TRX_UNDO_PAGE); data_field_len = ufield->new_val.len; btr_free_externally_stored_field(index, data_field, data_field_len, FALSE, &mtr); mtr_commit(&mtr); } } } /*************************************************************** Parses the row reference and other info in a modify undo log record. */ static ibool row_purge_parse_undo_rec( /*=====================*/ /* out: TRUE if purge operation required: NOTE that then the CALLER must unfreeze data dictionary! */ purge_node_t* node, /* in: row undo node */ ibool* updated_extern, /* out: TRUE if an externally stored field was updated */ que_thr_t* thr) /* in: query thread */ { dict_index_t* clust_index; byte* ptr; trx_t* trx; dulint undo_no; dulint table_id; dulint trx_id; dulint roll_ptr; ulint info_bits; ulint type; ulint cmpl_info; ut_ad(node && thr); trx = thr_get_trx(thr); ptr = trx_undo_rec_get_pars(node->undo_rec, &type, &cmpl_info, updated_extern, &undo_no, &table_id); node->rec_type = type; if (type == TRX_UNDO_UPD_DEL_REC && !(*updated_extern)) { return(FALSE); } ptr = trx_undo_update_rec_get_sys_cols(ptr, &trx_id, &roll_ptr, &info_bits); node->table = NULL; if (type == TRX_UNDO_UPD_EXIST_REC && cmpl_info & UPD_NODE_NO_ORD_CHANGE && !(*updated_extern)) { /* Purge requires no changes to indexes: we may return */ return(FALSE); } /* Prevent DROP TABLE etc. from running when we are doing the purge for this row */ row_mysql_freeze_data_dictionary(trx); mutex_enter(&(dict_sys->mutex)); node->table = dict_table_get_on_id_low(table_id, thr_get_trx(thr)); mutex_exit(&(dict_sys->mutex)); if (node->table == NULL) { /* The table has been dropped: no need to do purge */ row_mysql_unfreeze_data_dictionary(trx); return(FALSE); } if (node->table->ibd_file_missing) { /* We skip purge of missing .ibd files */ node->table = NULL; return(FALSE); } clust_index = dict_table_get_first_index(node->table); if (clust_index == NULL) { /* The table was corrupt in the data dictionary */ row_mysql_unfreeze_data_dictionary(trx); return(FALSE); } ptr = trx_undo_rec_get_row_ref(ptr, clust_index, &(node->ref), node->heap); ptr = trx_undo_update_rec_get_update(ptr, clust_index, type, trx_id, roll_ptr, info_bits, node->heap, &(node->update)); /* Read to the partial row the fields that occur in indexes */ if (!cmpl_info & UPD_NODE_NO_ORD_CHANGE) { ptr = trx_undo_rec_get_partial_row(ptr, clust_index, &(node->row), node->heap); } return(TRUE); } /*************************************************************** 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 ulint row_purge( /*======*/ /* out: DB_SUCCESS if operation successfully completed, else error code */ purge_node_t* node, /* in: row purge node */ que_thr_t* thr) /* in: query thread */ { dulint roll_ptr; ibool purge_needed; ibool updated_extern; trx_t* trx; ut_ad(node && thr); trx = thr_get_trx(thr); node->undo_rec = trx_purge_fetch_next_rec(&roll_ptr, &(node->reservation), node->heap); if (!node->undo_rec) { /* Purge completed for this query thread */ thr->run_node = que_node_get_parent(node); return(DB_SUCCESS); } node->roll_ptr = roll_ptr; if (node->undo_rec == &trx_purge_dummy_rec) { purge_needed = FALSE; } else { purge_needed = row_purge_parse_undo_rec(node, &updated_extern, thr); /* If purge_needed == TRUE, we must also remember to unfreeze data dictionary! */ } if (purge_needed) { node->found_clust = FALSE; node->index = dict_table_get_next_index( dict_table_get_first_index(node->table)); if (node->rec_type == TRX_UNDO_DEL_MARK_REC) { row_purge_del_mark(node, thr); } else if (updated_extern || node->rec_type == TRX_UNDO_UPD_EXIST_REC) { row_purge_upd_exist_or_extern(node, thr); } if (node->found_clust) { btr_pcur_close(&(node->pcur)); } row_mysql_unfreeze_data_dictionary(trx); } /* Do some cleanup */ trx_purge_rec_release(node->reservation); mem_heap_empty(node->heap); thr->run_node = node; return(DB_SUCCESS); } /*************************************************************** Does the purge operation for a single undo log record. This is a high-level function used in an SQL execution graph. */ que_thr_t* row_purge_step( /*===========*/ /* out: query thread to run next or NULL */ que_thr_t* thr) /* in: query thread */ { purge_node_t* node; ulint err; ut_ad(thr); node = thr->run_node; ut_ad(que_node_get_type(node) == QUE_NODE_PURGE); err = row_purge(node, thr); ut_ad(err == DB_SUCCESS); return(thr); }