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This is a complete rewrite of DROP TABLE, also as part of other DDL, such as ALTER TABLE, CREATE TABLE...SELECT, TRUNCATE TABLE. The background DROP TABLE queue hack is removed. If a transaction needs to drop and create a table by the same name (like TRUNCATE TABLE does), it must first rename the table to an internal #sql-ib name. No committed version of the data dictionary will include any #sql-ib tables, because whenever a transaction renames a table to a #sql-ib name, it will also drop that table. Either the rename will be rolled back, or the drop will be committed. Data files will be unlinked after the transaction has been committed and a FILE_RENAME record has been durably written. The file will actually be deleted when the detached file handle returned by fil_delete_tablespace() will be closed, after the latches have been released. It is possible that a purge of the delete of the SYS_INDEXES record for the clustered index will execute fil_delete_tablespace() concurrently with the DDL transaction. In that case, the thread that arrives later will wait for the other thread to finish. HTON_TRUNCATE_REQUIRES_EXCLUSIVE_USE: A new handler flag. ha_innobase::truncate() now requires that all other references to the table be released in advance. This was implemented by Monty. ha_innobase::delete_table(): If CREATE TABLE..SELECT is detected, we will "hijack" the current transaction, drop the table in the current transaction and commit the current transaction. This essentially fixes MDEV-21602. There is a FIXME comment about making the check less failure-prone. ha_innobase::truncate(), ha_innobase::delete_table(): Implement a fast path for temporary tables. We will no longer allow temporary tables to use the adaptive hash index. dict_table_t::mdl_name: The original table name for the purpose of acquiring MDL in purge, to prevent a race condition between a DDL transaction that is dropping a table, and purge processing undo log records of DML that had executed before the DDL operation. For #sql-backup- tables during ALTER TABLE...ALGORITHM=COPY, the dict_table_t::mdl_name will differ from dict_table_t::name. dict_table_t::parse_name(): Use mdl_name instead of name. dict_table_rename_in_cache(): Update mdl_name. For the internal FTS_ tables of FULLTEXT INDEX, purge would acquire MDL on the FTS_ table name, but not on the main table, and therefore it would be able to run concurrently with a DDL transaction that is dropping the table. Previously, the DROP TABLE queue hack prevented a race between purge and DDL. For now, we introduce purge_sys.stop_FTS() to prevent purge from opening any table, while a DDL transaction that may drop FTS_ tables is in progress. The function fts_lock_table(), which will be invoked before the dictionary is locked, will wait for purge to release any table handles. trx_t::drop_table_statistics(): Drop statistics for the table. This replaces dict_stats_drop_index(). We will drop or rename persistent statistics atomically as part of DDL transactions. On lock conflict for dropping statistics, we will fail instantly with DB_LOCK_WAIT_TIMEOUT, because we will be holding the exclusive data dictionary latch. trx_t::commit_cleanup(): Separated from trx_t::commit_in_memory(). Relax an assertion around fts_commit() and allow DB_LOCK_WAIT_TIMEOUT in addition to DB_DUPLICATE_KEY. The call to fts_commit() is entirely misplaced here and may obviously break the consistency of transactions that affect FULLTEXT INDEX. It needs to be fixed separately. dict_table_t::n_foreign_key_checks_running: Remove (MDEV-21175). The counter was a work-around for missing meta-data locking (MDL) on the SQL layer, and not really needed in MariaDB. ER_TABLE_IN_FK_CHECK: Replaced with ER_UNUSED_28. HA_ERR_TABLE_IN_FK_CHECK: Remove. row_ins_check_foreign_constraints(): Do not acquire dict_sys.latch either. The SQL-layer MDL will protect us. This was reviewed by Thirunarayanan Balathandayuthapani and tested by Matthias Leich.
68 lines
2.4 KiB
Text
68 lines
2.4 KiB
Text
/*****************************************************************************
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Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
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Copyright (c) 2017, 2021, MariaDB Corporation.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/******************************************************************//**
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@file include/dict0mem.ic
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Data dictionary memory object creation
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Created 1/8/1996 Heikki Tuuri
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***********************************************************************/
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#include "data0type.h"
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#include "dict0mem.h"
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#include "fil0fil.h"
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/**********************************************************************//**
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This function poplulates a dict_index_t index memory structure with
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supplied information. */
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UNIV_INLINE
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void
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dict_mem_fill_index_struct(
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/*=======================*/
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dict_index_t* index, /*!< out: index to be filled */
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mem_heap_t* heap, /*!< in: memory heap */
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const char* index_name, /*!< in: index name */
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ulint type, /*!< in: DICT_UNIQUE,
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DICT_CLUSTERED, ... ORed */
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ulint n_fields) /*!< in: number of fields */
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{
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if (heap) {
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index->heap = heap;
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index->name = mem_heap_strdup(heap, index_name);
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index->fields = (dict_field_t*) mem_heap_alloc(
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heap, 1 + n_fields * sizeof(dict_field_t));
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} else {
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index->name = index_name;
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index->heap = NULL;
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index->fields = NULL;
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}
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index->type = type & ((1U << DICT_IT_BITS) - 1);
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index->page = FIL_NULL;
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index->merge_threshold = DICT_INDEX_MERGE_THRESHOLD_DEFAULT;
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index->n_fields = static_cast<unsigned>(n_fields)
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& index->MAX_N_FIELDS;
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index->n_core_fields = static_cast<unsigned>(n_fields)
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& index->MAX_N_FIELDS;
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/* The '1 +' above prevents allocation
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of an empty mem block */
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index->nulls_equal = false;
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ut_d(index->magic_n = DICT_INDEX_MAGIC_N);
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}
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