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82b7c561b7
In the parent commit, dict_sys.latch could theoretically have been
replaced with a mutex. But, we can do better and merge dict_sys.mutex
into dict_sys.latch. Generally, every occurrence of dict_sys.mutex_lock()
will be replaced with dict_sys.lock().
The PERFORMANCE_SCHEMA instrumentation for dict_sys_mutex
will be removed along with dict_sys.mutex. The dict_sys.latch
will remain instrumented as dict_operation_lock.
Some use of dict_sys.lock() will be replaced with dict_sys.freeze(),
which we will reintroduce for the new shared mode. Most notably,
concurrent table lookups are possible as long as the tables are present
in the dict_sys cache. In particular, this will allow more concurrency
among InnoDB purge workers.
Because dict_sys.mutex will no longer 'throttle' the threads that purge
InnoDB transaction history, a performance degradation may be observed
unless innodb_purge_threads=1.
The table cache eviction policy will become FIFO-like,
similar to what happened to fil_system.LRU
in commit 45ed9dd957.
The name of the list dict_sys.table_LRU will become somewhat misleading;
that list contains tables that may be evicted, even though the
eviction policy no longer is least-recently-used but first-in-first-out.
(Note: Tables can never be evicted as long as locks exist on them or
the tables are in use by some thread.)
As demonstrated by the test perfschema.sxlock_func, there
will be less contention on dict_sys.latch, because some previous
use of exclusive latches will be replaced with shared latches.
fts_parse_sql_no_dict_lock(): Replaced with pars_sql().
fts_get_table_name_prefix(): Merged to fts_optimize_create().
dict_stats_update_transient_for_index(): Deduplicated some code.
ha_innobase::info_low(), dict_stats_stop_bg(): Use a combination
of dict_sys.latch and table->stats_mutex_lock() to cover the
changes of BG_STAT_SHOULD_QUIT, because the flag is being read
in dict_stats_update_persistent() while not holding dict_sys.latch.
row_discard_tablespace_for_mysql(): Protect stats_bg_flag by
exclusive dict_sys.latch, like most other code does.
row_quiesce_table_has_fts_index(): Remove unnecessary mutex
acquisition. FLUSH TABLES...FOR EXPORT is protected by MDL.
row_import::set_root_by_heuristic(): Remove unnecessary mutex
acquisition. ALTER TABLE...IMPORT TABLESPACE is protected by MDL.
row_ins_sec_index_entry_low(): Replace a call
to dict_set_corrupted_index_cache_only(). Reads of index->type
were not really protected by dict_sys.mutex, and writes
(flagging an index corrupted) should be extremely rare.
dict_stats_process_entry_from_defrag_pool(): Only freeze the dictionary,
do not lock it exclusively.
dict_stats_wait_bg_to_stop_using_table(), DICT_BG_YIELD: Remove trx.
We can simply invoke dict_sys.unlock() and dict_sys.lock() directly.
dict_acquire_mdl_shared()<trylock=false>: Assert that dict_sys.latch is
only held in shared more, not exclusive mode. Only acquire it in
exclusive mode if the table needs to be loaded to the cache.
dict_sys_t::acquire(): Remove. Relocating elements in dict_sys.table_LRU
would require holding an exclusive latch, which we want to avoid
for performance reasons.
dict_sys_t::allow_eviction(): Add the table first to dict_sys.table_LRU,
to compensate for the removal of dict_sys_t::acquire(). This function
is only invoked by INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS.
dict_table_open_on_id(), dict_table_open_on_name(): If dict_locked=false,
try to acquire dict_sys.latch in shared mode. Only acquire the latch in
exclusive mode if the table is not found in the cache.
Reviewed by: Thirunarayanan Balathandayuthapani
219 lines
8.8 KiB
C++
219 lines
8.8 KiB
C++
/*****************************************************************************
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Copyright (c) 1996, 2016, 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/dict0load.h
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Loads to the memory cache database object definitions
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from dictionary tables
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Created 4/24/1996 Heikki Tuuri
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*******************************************************/
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#ifndef dict0load_h
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#define dict0load_h
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#include "dict0types.h"
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#include "trx0types.h"
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#include "ut0byte.h"
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#include "mem0mem.h"
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#include "btr0types.h"
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#include <deque>
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/** A stack of table names related through foreign key constraints */
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typedef std::deque<const char*, ut_allocator<const char*> > dict_names_t;
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/** Check each tablespace found in the data dictionary.
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Then look at each table defined in SYS_TABLES that has a space_id > 0
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to find all the file-per-table tablespaces.
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In a crash recovery we already have some tablespace objects created from
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processing the REDO log. We will compare the
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space_id information in the data dictionary to what we find in the
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tablespace file. In addition, more validation will be done if recovery
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was needed and force_recovery is not set.
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We also scan the biggest space id, and store it to fil_system. */
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void dict_check_tablespaces_and_store_max_id();
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/** Make sure the data_file_name is saved in dict_table_t if needed.
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@param[in,out] table Table object
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@param[in] dict_locked dict_sys.frozen() */
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void dict_get_and_save_data_dir_path(dict_table_t* table, bool dict_locked);
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/***********************************************************************//**
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Loads a table object based on the table id.
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@return table; NULL if table does not exist */
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dict_table_t*
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dict_load_table_on_id(
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/*==================*/
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table_id_t table_id, /*!< in: table id */
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dict_err_ignore_t ignore_err); /*!< in: errors to ignore
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when loading the table */
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/********************************************************************//**
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This function is called when the database is booted.
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Loads system table index definitions except for the clustered index which
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is added to the dictionary cache at booting before calling this function. */
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void
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dict_load_sys_table(
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/*================*/
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dict_table_t* table); /*!< in: system table */
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/***********************************************************************//**
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Loads foreign key constraints where the table is either the foreign key
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holder or where the table is referenced by a foreign key. Adds these
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constraints to the data dictionary.
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The foreign key constraint is loaded only if the referenced table is also
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in the dictionary cache. If the referenced table is not in dictionary
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cache, then it is added to the output parameter (fk_tables).
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@return DB_SUCCESS or error code */
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dberr_t
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dict_load_foreigns(
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/*===============*/
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const char* table_name, /*!< in: table name */
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const char** col_names, /*!< in: column names, or NULL
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to use table->col_names */
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bool check_recursive,/*!< in: Whether to check
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recursive load of tables
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chained by FK */
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bool check_charsets, /*!< in: whether to check
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charset compatibility */
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dict_err_ignore_t ignore_err, /*!< in: error to be ignored */
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dict_names_t& fk_tables) /*!< out: stack of table names
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which must be loaded
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subsequently to load all the
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foreign key constraints. */
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MY_ATTRIBUTE((nonnull(1), warn_unused_result));
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/********************************************************************//**
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This function opens a system table, and return the first record.
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@return first record of the system table */
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const rec_t*
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dict_startscan_system(
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/*==================*/
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btr_pcur_t* pcur, /*!< out: persistent cursor to
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the record */
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mtr_t* mtr, /*!< in: the mini-transaction */
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dict_table_t* table); /*!< in: system table */
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/********************************************************************//**
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This function get the next system table record as we scan the table.
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@return the record if found, NULL if end of scan. */
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const rec_t*
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dict_getnext_system(
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/*================*/
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btr_pcur_t* pcur, /*!< in/out: persistent cursor
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to the record */
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mtr_t* mtr); /*!< in: the mini-transaction */
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/** Load a table definition from a SYS_TABLES record to dict_table_t.
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Do not load any columns or indexes.
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@param[in] name Table name
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@param[in] rec SYS_TABLES record
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@param[out,own] table table, or nullptr
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@return error message
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@retval nullptr on success */
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const char *dict_load_table_low(const span<const char> &name,
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const rec_t *rec, dict_table_t **table)
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MY_ATTRIBUTE((nonnull, warn_unused_result));
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/********************************************************************//**
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This function parses a SYS_INDEXES record and populate a dict_index_t
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structure with the information from the record. For detail information
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about SYS_INDEXES fields, please refer to dict_boot() function.
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@return error message, or NULL on success */
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const char*
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dict_process_sys_indexes_rec(
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/*=========================*/
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mem_heap_t* heap, /*!< in/out: heap memory */
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const rec_t* rec, /*!< in: current SYS_INDEXES rec */
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dict_index_t* index, /*!< out: dict_index_t to be
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filled */
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table_id_t* table_id); /*!< out: table id */
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/********************************************************************//**
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This function parses a SYS_COLUMNS record and populate a dict_column_t
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structure with the information from the record.
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@return error message, or NULL on success */
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const char*
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dict_process_sys_columns_rec(
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/*=========================*/
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mem_heap_t* heap, /*!< in/out: heap memory */
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const rec_t* rec, /*!< in: current SYS_COLUMNS rec */
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dict_col_t* column, /*!< out: dict_col_t to be filled */
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table_id_t* table_id, /*!< out: table id */
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const char** col_name, /*!< out: column name */
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ulint* nth_v_col); /*!< out: if virtual col, this is
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records its sequence number */
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/** This function parses a SYS_VIRTUAL record and extract virtual column
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information
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@param[in,out] heap heap memory
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@param[in] rec current SYS_COLUMNS rec
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@param[in,out] table_id table id
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@param[in,out] pos virtual column position
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@param[in,out] base_pos base column position
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@return error message, or NULL on success */
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const char*
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dict_process_sys_virtual_rec(
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const rec_t* rec,
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table_id_t* table_id,
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ulint* pos,
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ulint* base_pos);
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/********************************************************************//**
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This function parses a SYS_FIELDS record and populate a dict_field_t
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structure with the information from the record.
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@return error message, or NULL on success */
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const char*
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dict_process_sys_fields_rec(
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/*========================*/
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mem_heap_t* heap, /*!< in/out: heap memory */
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const rec_t* rec, /*!< in: current SYS_FIELDS rec */
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dict_field_t* sys_field, /*!< out: dict_field_t to be
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filled */
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ulint* pos, /*!< out: Field position */
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index_id_t* index_id, /*!< out: current index id */
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index_id_t last_id); /*!< in: previous index id */
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/********************************************************************//**
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This function parses a SYS_FOREIGN record and populate a dict_foreign_t
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structure with the information from the record. For detail information
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about SYS_FOREIGN fields, please refer to dict_load_foreign() function
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@return error message, or NULL on success */
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const char*
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dict_process_sys_foreign_rec(
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/*=========================*/
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mem_heap_t* heap, /*!< in/out: heap memory */
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const rec_t* rec, /*!< in: current SYS_FOREIGN rec */
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dict_foreign_t* foreign); /*!< out: dict_foreign_t to be
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filled */
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/********************************************************************//**
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This function parses a SYS_FOREIGN_COLS record and extract necessary
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information from the record and return to caller.
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@return error message, or NULL on success */
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const char*
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dict_process_sys_foreign_col_rec(
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/*=============================*/
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mem_heap_t* heap, /*!< in/out: heap memory */
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const rec_t* rec, /*!< in: current SYS_FOREIGN_COLS rec */
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const char** name, /*!< out: foreign key constraint name */
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const char** for_col_name, /*!< out: referencing column name */
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const char** ref_col_name, /*!< out: referenced column name
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in referenced table */
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ulint* pos); /*!< out: column position */
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#endif
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