/*****************************************************************************

Copyright (c) 2009, 2018, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, 2018, 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 include/dict0stats.h
Code used for calculating and manipulating table statistics.

Created Jan 06, 2010 Vasil Dimov
*******************************************************/

#ifndef dict0stats_h
#define dict0stats_h

#include "dict0types.h"
#include "trx0types.h"

#define TABLE_STATS_NAME        "mysql/innodb_table_stats"
#define INDEX_STATS_NAME        "mysql/innodb_index_stats"

enum dict_stats_upd_option_t {
	DICT_STATS_RECALC_PERSISTENT,/* (re) calculate the
				statistics using a precise and slow
				algo and save them to the persistent
				storage, if the persistent storage is
				not present then emit a warning and
				fall back to transient stats */
	DICT_STATS_RECALC_TRANSIENT,/* (re) calculate the statistics
				using an imprecise quick algo
				without saving the results
				persistently */
	DICT_STATS_EMPTY_TABLE,	/* Write all zeros (or 1 where it makes sense)
				into a table and its indexes' statistics
				members. The resulting stats correspond to an
				empty table. If the table is using persistent
				statistics, then they are saved on disk. */
	DICT_STATS_FETCH_ONLY_IF_NOT_IN_MEMORY /* fetch the stats
				from the persistent storage if the in-memory
				structures have not been initialized yet,
				otherwise do nothing */
};

/*********************************************************************//**
Set the persistent statistics flag for a given table. This is set only
in the in-memory table object and is not saved on disk. It will be read
from the .frm file upon first open from MySQL after a server restart. */
UNIV_INLINE
void
dict_stats_set_persistent(
/*======================*/
	dict_table_t*	table,	/*!< in/out: table */
	ibool		ps_on,	/*!< in: persistent stats explicitly enabled */
	ibool		ps_off)	/*!< in: persistent stats explicitly disabled */
	MY_ATTRIBUTE((nonnull));

/** @return whether persistent statistics is enabled for a given table */
UNIV_INLINE
bool
dict_stats_is_persistent_enabled(const dict_table_t* table)
	MY_ATTRIBUTE((nonnull, warn_unused_result));

/*********************************************************************//**
Set the auto recalc flag for a given table (only honored for a persistent
stats enabled table). The flag is set only in the in-memory table object
and is not saved in InnoDB files. It will be read from the .frm file upon
first open from MySQL after a server restart. */
UNIV_INLINE
void
dict_stats_auto_recalc_set(
/*=======================*/
	dict_table_t*	table,			/*!< in/out: table */
	ibool		auto_recalc_on,		/*!< in: explicitly enabled */
	ibool		auto_recalc_off);	/*!< in: explicitly disabled */

/** @return whether auto recalc is enabled for a given table*/
UNIV_INLINE
bool
dict_stats_auto_recalc_is_enabled(const dict_table_t* table)
	MY_ATTRIBUTE((nonnull, warn_unused_result));

/*********************************************************************//**
Initialize table's stats for the first time when opening a table. */
UNIV_INLINE
void
dict_stats_init(
/*============*/
	dict_table_t*	table);	/*!< in/out: table */

/*********************************************************************//**
Deinitialize table's stats after the last close of the table. This is
used to detect "FLUSH TABLE" and refresh the stats upon next open. */
UNIV_INLINE
void
dict_stats_deinit(
/*==============*/
	dict_table_t*	table)	/*!< in/out: table */
	MY_ATTRIBUTE((nonnull));

#ifdef WITH_WSREP
/** Update the table modification counter and if necessary,
schedule new estimates for table and index statistics to be calculated.
@param[in,out]	table	persistent or temporary table
@param[in]	thd	current session */
void dict_stats_update_if_needed(dict_table_t* table, THD* thd)
	MY_ATTRIBUTE((nonnull(1)));
#else
/** Update the table modification counter and if necessary,
schedule new estimates for table and index statistics to be calculated.
@param[in,out]	table	persistent or temporary table */
void dict_stats_update_if_needed_func(dict_table_t* table)
	MY_ATTRIBUTE((nonnull));
# define dict_stats_update_if_needed(t,thd) dict_stats_update_if_needed_func(t)
#endif

/*********************************************************************//**
Calculates new estimates for table and index statistics. The statistics
are used in query optimization.
@return DB_* error code or DB_SUCCESS */
dberr_t
dict_stats_update(
/*==============*/
	dict_table_t*		table,	/*!< in/out: table */
	dict_stats_upd_option_t	stats_upd_option);
					/*!< in: whether to (re) calc
					the stats or to fetch them from
					the persistent storage */

/*********************************************************************//**
Removes the information for a particular index's stats from the persistent
storage if it exists and if there is data stored for this index.
This function creates its own trx and commits it.
@return DB_SUCCESS or error code */
dberr_t
dict_stats_drop_index(
/*==================*/
	const char*	tname,	/*!< in: table name */
	const char*	iname,	/*!< in: index name */
	char*		errstr, /*!< out: error message if != DB_SUCCESS
				is returned */
	ulint		errstr_sz);/*!< in: size of the errstr buffer */

/*********************************************************************//**
Removes the statistics for a table and all of its indexes from the
persistent storage if it exists and if there is data stored for the table.
This function creates its own transaction and commits it.
@return DB_SUCCESS or error code */
dberr_t
dict_stats_drop_table(
/*==================*/
	const char*	table_name,	/*!< in: table name */
	char*		errstr,		/*!< out: error message
					if != DB_SUCCESS is returned */
	ulint		errstr_sz);	/*!< in: size of errstr buffer */

/*********************************************************************//**
Fetches or calculates new estimates for index statistics. */
void
dict_stats_update_for_index(
/*========================*/
	dict_index_t*	index)	/*!< in/out: index */
	MY_ATTRIBUTE((nonnull));

/*********************************************************************//**
Renames a table in InnoDB persistent stats storage.
This function creates its own transaction and commits it.
@return DB_SUCCESS or error code */
dberr_t
dict_stats_rename_table(
/*====================*/
	const char*	old_name,	/*!< in: old table name */
	const char*	new_name,	/*!< in: new table name */
	char*		errstr,		/*!< out: error string if != DB_SUCCESS
					is returned */
	size_t		errstr_sz);	/*!< in: errstr size */
/*********************************************************************//**
Renames an index in InnoDB persistent stats storage.
This function creates its own transaction and commits it.
@return DB_SUCCESS or error code. DB_STATS_DO_NOT_EXIST will be returned
if the persistent stats do not exist. */
dberr_t
dict_stats_rename_index(
/*====================*/
	const dict_table_t*	table,		/*!< in: table whose index
						is renamed */
	const char*		old_index_name,	/*!< in: old index name */
	const char*		new_index_name)	/*!< in: new index name */
	__attribute__((warn_unused_result));

/** Save an individual index's statistic into the persistent statistics
storage.
@param[in]	index			index to be updated
@param[in]	last_update		timestamp of the stat
@param[in]	stat_name		name of the stat
@param[in]	stat_value		value of the stat
@param[in]	sample_size		n pages sampled or NULL
@param[in]	stat_description	description of the stat
@param[in,out]	trx			in case of NULL the function will
allocate and free the trx object. If it is not NULL then it will be
rolled back only in the case of error, but not freed.
@return DB_SUCCESS or error code */
dberr_t
dict_stats_save_index_stat(
	dict_index_t*	index,
	ib_time_t	last_update,
	const char*	stat_name,
	ib_uint64_t	stat_value,
	ib_uint64_t*	sample_size,
	const char*	stat_description,
	trx_t*		trx);

/** Report an error if updating table statistics failed because
.ibd file is missing, table decryption failed or table is corrupted.
@param[in,out]	table	Table
@param[in]	defragment	true if statistics is for defragment
@retval DB_DECRYPTION_FAILED if decryption of the table failed
@retval DB_TABLESPACE_DELETED if .ibd file is missing
@retval DB_CORRUPTION if table is marked as corrupted */
dberr_t
dict_stats_report_error(dict_table_t* table, bool defragment = false)
	MY_ATTRIBUTE((nonnull, warn_unused_result));

#include "dict0stats.ic"

#ifdef UNIV_ENABLE_UNIT_TEST_DICT_STATS
void test_dict_stats_all();
#endif /* UNIV_ENABLE_UNIT_TEST_DICT_STATS */

#endif /* dict0stats_h */