ea37b14409
This is joint work with Thirunarayanan Balathandayuthapani. The MDL interface between InnoDB and the rest of the server (in storage/innobase/dict/dict0dict.cc and in include/) is my work, while most everything else is Thiru's. The collection of InnoDB persistent statistics and the defragmentation were not refactored to use MDL. They will keep relying on lower-level interlocking with fil_check_pending_operations(). The purge of transaction history and the background operations on fulltext indexes will use MDL. We will revert commit 2c4844c9e76427525e8c39a2d72686085efe89c3 (MDEV-17813) because thanks to MDL, purge cannot conflict with DDL operations anymore. For a similar reason, we will remove the MDEV-16222 test case from gcol.innodb_virtual_debug_purge. Purge is essentially replacing all use of the global dict_sys.latch with MDL. Purge will skip the undo log records for tables whose names start with #sql-ib or #sql2. Theoretically, such tables might be renamed back to visible table names if TRUNCATE fails to create a new table, or the final rename in ALTER TABLE...ALGORITHM=COPY fails. In that case, purge could permanently leave some garbage in the table. Such garbage will be tolerated; the table would not be considered corrupted. To avoid repeated MDL releases and acquisitions, trx_purge_attach_undo_recs() will sort undo log records by table_id, and purge_node_t will keep the MDL and table handle open for multiple successive undo log records. get_purge_table(): A new accessor, used during the purge of history for indexed virtual columns. This interface should ideally not exist at all. thd_mdl_context(): Accessor of THD::mdl_context. Wrapped in a new thd_mdl_service. dict_get_db_name_len(): Define inline. dict_acquire_mdl_shared(): Acquire explicit shared MDL on a table name if needed. dict_table_open_on_id(): Return MDL_ticket, if requested. dict_table_close(): Release MDL ticket, if requested. dict_fts_index_syncing(), dict_index_t::index_fts_syncing: Remove. row_drop_table_for_mysql() no longer needs to check these, because MDL guarantees that a fulltext index sync will not be in progress while MDL_EXCLUSIVE is protecting a DDL operation. dict_table_t::parse_name(): Parse the table name for acquiring MDL. purge_node_t::undo_recs: Change the type to std::list<trx_purge_rec_t*> (different container, and storing also roll_ptr). purge_node_t: Add mdl_ticket, last_table_id, purge_thd, mdl_hold_recs for acquiring MDL and for keeping the table open across multiple undo log records. purge_vcol_info_t, row_purge_store_vsec_cur(), row_purge_restore_vsec_cur(): Remove. We will acquire the MDL earlier. purge_sys_t::heap: Added, for reading undo log records. fts_sync_during_ddl(): Invoked during ALGORITHM=INPLACE operations to ensure that fts_sync_table() will not conflict with MDL_EXCLUSIVE. Uses fts_t::sync_message for bookkeeping.
47 lines
1.3 KiB
C
47 lines
1.3 KiB
C
/* Copyright (c) 2019, MariaDB Corporation.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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#pragma once
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/**
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@file include/mysql/service_thd_mdl.h
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This service provides functions for plugins and storage engines to access
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metadata locks.
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern struct thd_mdl_service_st {
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void *(*thd_mdl_context)(MYSQL_THD);
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} *thd_mdl_service;
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#ifdef MYSQL_DYNAMIC_PLUGIN
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# define thd_mdl_context(_THD) thd_mdl_service->thd_mdl_context(_THD)
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#else
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/**
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MDL_context accessor
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@param thd the current session
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@return pointer to thd->mdl_context
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*/
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void *thd_mdl_context(MYSQL_THD thd);
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#endif
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#ifdef __cplusplus
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}
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#endif
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