1 /* Copyright (c) 2015, 2021, Oracle and/or its affiliates.
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License, version 2.0,
5 as published by the Free Software Foundation.
6
7 This program is also distributed with certain software (including
8 but not limited to OpenSSL) that is licensed under separate terms,
9 as designated in a particular file or component or in included license
10 documentation. The authors of MySQL hereby grant you an additional
11 permission to link the program and your derivative works with the
12 separately licensed software that they have included with MySQL.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License, version 2.0, for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
22
23 /**
24 @file storage/perfschema/table_global_variables.cc
25 Table GLOBAL_VARIABLES (implementation).
26 */
27
28 #include "my_global.h"
29 #include "table_global_variables.h"
30 #include "my_thread.h"
31 #include "pfs_instr_class.h"
32 #include "pfs_column_types.h"
33 #include "pfs_column_values.h"
34 #include "pfs_global.h"
35
36 THR_LOCK table_global_variables::m_table_lock;
37
38 PFS_engine_table_share
39 table_global_variables::m_share=
40 {
41 { C_STRING_WITH_LEN("global_variables") },
42 &pfs_readonly_world_acl,
43 table_global_variables::create,
44 NULL, /* write_row */
45 NULL, /* delete_all_rows */
46 table_global_variables::get_row_count,
47 sizeof(pos_t),
48 &m_table_lock,
49 { C_STRING_WITH_LEN("CREATE TABLE global_variables("
50 "VARIABLE_NAME VARCHAR(64) not null,"
51 "VARIABLE_VALUE VARCHAR(1024))") },
52 true /* perpetual */
53 };
54
55 PFS_engine_table*
create(void)56 table_global_variables::create(void)
57 {
58 return new table_global_variables();
59 }
60
get_row_count(void)61 ha_rows table_global_variables::get_row_count(void)
62 {
63 mysql_mutex_lock(&LOCK_plugin_delete);
64 mysql_prlock_rdlock(&LOCK_system_variables_hash);
65 ha_rows system_var_count= get_system_variable_hash_records();
66 mysql_prlock_unlock(&LOCK_system_variables_hash);
67 mysql_mutex_unlock(&LOCK_plugin_delete);
68 return system_var_count;
69 }
70
table_global_variables()71 table_global_variables::table_global_variables()
72 : PFS_engine_table(&m_share, &m_pos),
73 m_sysvar_cache(false), m_row_exists(false), m_pos(0), m_next_pos(0)
74 {}
75
reset_position(void)76 void table_global_variables::reset_position(void)
77 {
78 m_pos.m_index= 0;
79 m_next_pos.m_index= 0;
80 }
81
rnd_init(bool scan)82 int table_global_variables::rnd_init(bool scan)
83 {
84 /*
85 Build a list of system variables from the global system variable hash.
86 Filter by scope.
87 */
88 m_sysvar_cache.materialize_global();
89
90 /* Record the version of the system variable hash. */
91 ulonglong hash_version= m_sysvar_cache.get_sysvar_hash_version();
92
93 /*
94 The table context holds the current version of the system variable hash.
95 If scan == true, then allocate a new context from mem_root and store in TLS.
96 If scan == false, then restore from TLS.
97 */
98 m_context= (table_global_variables_context *)current_thd->alloc(sizeof(table_global_variables_context));
99 new(m_context) table_global_variables_context(hash_version, !scan);
100 return 0;
101 }
102
rnd_next(void)103 int table_global_variables::rnd_next(void)
104 {
105 for (m_pos.set_at(&m_next_pos);
106 m_pos.m_index < m_sysvar_cache.size();
107 m_pos.next())
108 {
109 const System_variable *system_var= m_sysvar_cache.get(m_pos.m_index);
110 if (system_var != NULL)
111 {
112 make_row(system_var);
113 m_next_pos.set_after(&m_pos);
114 return 0;
115 }
116 }
117 return HA_ERR_END_OF_FILE;
118 }
119
rnd_pos(const void * pos)120 int table_global_variables::rnd_pos(const void *pos)
121 {
122 /* If system variable hash changes, do nothing. */ // TODO: Issue warning
123 if (!m_context->versions_match())
124 return HA_ERR_RECORD_DELETED;
125
126 set_position(pos);
127 assert(m_pos.m_index < m_sysvar_cache.size());
128
129 const System_variable *system_var= m_sysvar_cache.get(m_pos.m_index);
130 if (system_var != NULL)
131 {
132 make_row(system_var);
133 return 0;
134 }
135 return HA_ERR_RECORD_DELETED;
136 }
137
138 void table_global_variables
make_row(const System_variable * system_var)139 ::make_row(const System_variable *system_var)
140 {
141 m_row_exists= false;
142 if (system_var->is_null() || system_var->is_ignored())
143 return;
144 m_row.m_variable_name.make_row(system_var->m_name, system_var->m_name_length);
145 m_row.m_variable_value.make_row(system_var);
146 m_row_exists= true;
147 }
148
149 int table_global_variables
read_row_values(TABLE * table,unsigned char * buf,Field ** fields,bool read_all)150 ::read_row_values(TABLE *table,
151 unsigned char *buf,
152 Field **fields,
153 bool read_all)
154 {
155 Field *f;
156
157 if (unlikely(! m_row_exists))
158 return HA_ERR_RECORD_DELETED;
159
160 /* Set the null bits */
161 assert(table->s->null_bytes == 1);
162 buf[0]= 0;
163
164 for (; (f= *fields) ; fields++)
165 {
166 if (read_all || bitmap_is_set(table->read_set, f->field_index))
167 {
168 switch(f->field_index)
169 {
170 case 0: /* VARIABLE_NAME */
171 set_field_varchar_utf8(f, m_row.m_variable_name.m_str, m_row.m_variable_name.m_length);
172 break;
173 case 1: /* VARIABLE_VALUE */
174 m_row.m_variable_value.set_field(f);
175 break;
176 default:
177 assert(false);
178 }
179 }
180 }
181
182 return 0;
183 }
184
185