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25 *****************************************************************************/
26 
27 /**************************************************//**
28 @file include/dict0stats.h
29 Code used for calculating and manipulating table statistics.
30 
31 Created Jan 06, 2010 Vasil Dimov
32 *******************************************************/
33 
34 #ifndef dict0stats_h
35 #define dict0stats_h
36 
37 #include "univ.i"
38 
39 #include "dict0types.h"
40 #include "trx0types.h"
41 
42 #define TABLE_STATS_NAME        "mysql/innodb_table_stats"
43 #define INDEX_STATS_NAME        "mysql/innodb_index_stats"
44 
45 enum dict_stats_upd_option_t {
46 	DICT_STATS_RECALC_PERSISTENT,/* (re) calculate the
47 				statistics using a precise and slow
48 				algo and save them to the persistent
49 				storage, if the persistent storage is
50 				not present then emit a warning and
51 				fall back to transient stats */
52 	DICT_STATS_RECALC_TRANSIENT,/* (re) calculate the statistics
53 				using an imprecise quick algo
54 				without saving the results
55 				persistently */
56 	DICT_STATS_EMPTY_TABLE,	/* Write all zeros (or 1 where it makes sense)
57 				into a table and its indexes' statistics
58 				members. The resulting stats correspond to an
59 				empty table. If the table is using persistent
60 				statistics, then they are saved on disk. */
61 	DICT_STATS_FETCH_ONLY_IF_NOT_IN_MEMORY /* fetch the stats
62 				from the persistent storage if the in-memory
63 				structures have not been initialized yet,
64 				otherwise do nothing */
65 };
66 
67 /*********************************************************************//**
68 Calculates new estimates for table and index statistics. This function
69 is relatively quick and is used to calculate transient statistics that
70 are not saved on disk.
71 This was the only way to calculate statistics before the
72 Persistent Statistics feature was introduced. */
73 void
74 dict_stats_update_transient(
75 /*========================*/
76 	dict_table_t*	table);	/*!< in/out: table */
77 
78 /*********************************************************************//**
79 Set the persistent statistics flag for a given table. This is set only
80 in the in-memory table object and is not saved on disk. It will be read
81 from the .frm file upon first open from MySQL after a server restart. */
82 UNIV_INLINE
83 void
84 dict_stats_set_persistent(
85 /*======================*/
86 	dict_table_t*	table,	/*!< in/out: table */
87 	ibool		ps_on,	/*!< in: persistent stats explicitly enabled */
88 	ibool		ps_off)	/*!< in: persistent stats explicitly disabled */
89 	MY_ATTRIBUTE((nonnull));
90 
91 /*********************************************************************//**
92 Check whether persistent statistics is enabled for a given table.
93 @return TRUE if enabled, FALSE otherwise */
94 UNIV_INLINE
95 ibool
96 dict_stats_is_persistent_enabled(
97 /*=============================*/
98 	const dict_table_t*	table)	/*!< in: table */
99 	MY_ATTRIBUTE((nonnull, warn_unused_result));
100 
101 /*********************************************************************//**
102 Set the auto recalc flag for a given table (only honored for a persistent
103 stats enabled table). The flag is set only in the in-memory table object
104 and is not saved in InnoDB files. It will be read from the .frm file upon
105 first open from MySQL after a server restart. */
106 UNIV_INLINE
107 void
108 dict_stats_auto_recalc_set(
109 /*=======================*/
110 	dict_table_t*	table,			/*!< in/out: table */
111 	ibool		auto_recalc_on,		/*!< in: explicitly enabled */
112 	ibool		auto_recalc_off);	/*!< in: explicitly disabled */
113 
114 /*********************************************************************//**
115 Check whether auto recalc is enabled for a given table.
116 @return TRUE if enabled, FALSE otherwise */
117 UNIV_INLINE
118 ibool
119 dict_stats_auto_recalc_is_enabled(
120 /*==============================*/
121 	const dict_table_t*	table);	/*!< in: table */
122 
123 /*********************************************************************//**
124 Initialize table's stats for the first time when opening a table. */
125 UNIV_INLINE
126 void
127 dict_stats_init(
128 /*============*/
129 	dict_table_t*	table);	/*!< in/out: table */
130 
131 /*********************************************************************//**
132 Deinitialize table's stats after the last close of the table. This is
133 used to detect "FLUSH TABLE" and refresh the stats upon next open. */
134 UNIV_INLINE
135 void
136 dict_stats_deinit(
137 /*==============*/
138 	dict_table_t*	table)	/*!< in/out: table */
139 	MY_ATTRIBUTE((nonnull));
140 
141 /*********************************************************************//**
142 Calculates new estimates for table and index statistics. The statistics
143 are used in query optimization.
144 @return DB_* error code or DB_SUCCESS */
145 dberr_t
146 dict_stats_update(
147 /*==============*/
148 	dict_table_t*		table,	/*!< in/out: table */
149 	dict_stats_upd_option_t	stats_upd_option);
150 					/*!< in: whether to (re) calc
151 					the stats or to fetch them from
152 					the persistent storage */
153 
154 /*********************************************************************//**
155 Removes the information for a particular index's stats from the persistent
156 storage if it exists and if there is data stored for this index.
157 This function creates its own trx and commits it.
158 @return DB_SUCCESS or error code */
159 dberr_t
160 dict_stats_drop_index(
161 /*==================*/
162 	const char*	tname,	/*!< in: table name */
163 	const char*	iname,	/*!< in: index name */
164 	char*		errstr, /*!< out: error message if != DB_SUCCESS
165 				is returned */
166 	ulint		errstr_sz);/*!< in: size of the errstr buffer */
167 
168 /*********************************************************************//**
169 Removes the statistics for a table and all of its indexes from the
170 persistent storage if it exists and if there is data stored for the table.
171 This function creates its own transaction and commits it.
172 @return DB_SUCCESS or error code */
173 dberr_t
174 dict_stats_drop_table(
175 /*==================*/
176 	const char*	table_name,	/*!< in: table name */
177 	char*		errstr,		/*!< out: error message
178 					if != DB_SUCCESS is returned */
179 	ulint		errstr_sz);	/*!< in: size of errstr buffer */
180 
181 /*********************************************************************//**
182 Fetches or calculates new estimates for index statistics. */
183 void
184 dict_stats_update_for_index(
185 /*========================*/
186 	dict_index_t*	index)	/*!< in/out: index */
187 	MY_ATTRIBUTE((nonnull));
188 
189 /*********************************************************************//**
190 Renames a table in InnoDB persistent stats storage.
191 This function creates its own transaction and commits it.
192 @return DB_SUCCESS or error code */
193 dberr_t
194 dict_stats_rename_table(
195 /*====================*/
196 	bool		dict_locked,	/*!< in: true if dict_sys mutex
197                                         and dict_operation_lock are held,
198                                         otherwise false*/
199 	const char*	old_name,	/*!< in: old table name */
200 	const char*	new_name,	/*!< in: new table name */
201 	char*		errstr,		/*!< out: error string if != DB_SUCCESS
202 					is returned */
203 	size_t		errstr_sz);	/*!< in: errstr size */
204 
205 /*********************************************************************//**
206 Renames an index in InnoDB persistent stats storage.
207 This function creates its own transaction and commits it.
208 @return DB_SUCCESS or error code. DB_STATS_DO_NOT_EXIST will be returned
209 if the persistent stats do not exist. */
210 dberr_t
211 dict_stats_rename_index(
212 /*====================*/
213 	const dict_table_t*	table,		/*!< in: table whose index
214 						is renamed */
215 	const char*		old_index_name,	/*!< in: old index name */
216 	const char*		new_index_name)	/*!< in: new index name */
217 	MY_ATTRIBUTE((warn_unused_result));
218 
219 #ifndef UNIV_NONINL
220 #include "dict0stats.ic"
221 #endif
222 
223 #ifdef UNIV_ENABLE_UNIT_TEST_DICT_STATS
224 void test_dict_stats_all();
225 #endif /* UNIV_ENABLE_UNIT_TEST_DICT_STATS */
226 
227 #endif /* dict0stats_h */
228