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_session_status.cc
25 Table SESSION_STATUS (implementation).
26 */
27
28 #include "my_global.h"
29 #include "my_thread.h"
30 #include "table_session_status.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_session_status::m_table_lock;
37
38 PFS_engine_table_share
39 table_session_status::m_share=
40 {
41 { C_STRING_WITH_LEN("session_status") },
42 &pfs_readonly_world_acl,
43 table_session_status::create,
44 NULL, /* write_row */
45 NULL, /* delete_all_rows */
46 table_session_status::get_row_count,
47 sizeof(pos_t),
48 &m_table_lock,
49 { C_STRING_WITH_LEN("CREATE TABLE session_status("
50 "VARIABLE_NAME VARCHAR(64) not null comment 'The session status variable name.',"
51 "VARIABLE_VALUE VARCHAR(1024) comment 'The session status variable value.')") },
52 true /* perpetual */
53 };
54
55 PFS_engine_table*
create(void)56 table_session_status::create(void)
57 {
58 return new table_session_status();
59 }
60
get_row_count(void)61 ha_rows table_session_status::get_row_count(void)
62 {
63 mysql_mutex_lock(&LOCK_status);
64 ha_rows status_var_count= all_status_vars.elements;
65 mysql_mutex_unlock(&LOCK_status);
66 return status_var_count;
67 }
68
table_session_status()69 table_session_status::table_session_status()
70 : PFS_engine_table(&m_share, &m_pos),
71 m_status_cache(false), m_row_exists(false), m_pos(0), m_next_pos(0)
72 {}
73
reset_position(void)74 void table_session_status::reset_position(void)
75 {
76 m_pos.m_index = 0;
77 m_next_pos.m_index = 0;
78 }
79
rnd_init(bool scan)80 int table_session_status::rnd_init(bool scan)
81 {
82 /* Build a cache of all status variables for this thread. */
83 m_status_cache.materialize_all(current_thd);
84
85 /* Record the current number of status variables to detect subsequent changes. */
86 ulonglong status_version= m_status_cache.get_status_array_version();
87
88 /*
89 The table context holds the current version of the global status array.
90 If scan == true, then allocate a new context from mem_root and store in TLS.
91 If scan == false, then restore from TLS.
92 */
93 m_context= (table_session_status_context *)current_thd->alloc(sizeof(table_session_status_context));
94 new(m_context) table_session_status_context(status_version, !scan);
95 return 0;
96 }
97
rnd_next(void)98 int table_session_status::rnd_next(void)
99 {
100 for (m_pos.set_at(&m_next_pos);
101 m_pos.m_index < m_status_cache.size();
102 m_pos.next())
103 {
104 if (m_status_cache.is_materialized())
105 {
106 const Status_variable *stat_var= m_status_cache.get(m_pos.m_index);
107 if (stat_var != NULL)
108 {
109 make_row(stat_var);
110 m_next_pos.set_after(&m_pos);
111 return 0;
112 }
113 }
114 }
115 return HA_ERR_END_OF_FILE;
116 }
117
118 int
rnd_pos(const void * pos)119 table_session_status::rnd_pos(const void *pos)
120 {
121 /* If global status array has changed, do nothing. */ // TODO: warning
122 if (!m_context->versions_match())
123 return HA_ERR_RECORD_DELETED;
124
125 set_position(pos);
126 assert(m_pos.m_index < m_status_cache.size());
127
128 if (m_status_cache.is_materialized())
129 {
130 const Status_variable *stat_var= m_status_cache.get(m_pos.m_index);
131 if (stat_var != NULL)
132 {
133 make_row(stat_var);
134 return 0;
135 }
136 }
137
138 return HA_ERR_RECORD_DELETED;
139 }
140
141 void table_session_status
make_row(const Status_variable * status_var)142 ::make_row(const Status_variable *status_var)
143 {
144 m_row_exists= false;
145 m_row.m_variable_name.make_row(status_var->m_name, status_var->m_name_length);
146 m_row.m_variable_value.make_row(status_var);
147 m_row_exists= true;
148 }
149
150 int table_session_status
read_row_values(TABLE * table,unsigned char * buf,Field ** fields,bool read_all)151 ::read_row_values(TABLE *table,
152 unsigned char *buf,
153 Field **fields,
154 bool read_all)
155 {
156 Field *f;
157
158 if (unlikely(!m_row_exists))
159 return HA_ERR_RECORD_DELETED;
160
161 /* Set the null bits */
162 assert(table->s->null_bytes == 1);
163 buf[0]= 0;
164
165 for (; (f= *fields) ; fields++)
166 {
167 if (read_all || bitmap_is_set(table->read_set, f->field_index))
168 {
169 switch(f->field_index)
170 {
171 case 0: /* VARIABLE_NAME */
172 set_field_varchar_utf8(f, m_row.m_variable_name.m_str, m_row.m_variable_name.m_length);
173 break;
174 case 1: /* VARIABLE_VALUE */
175 m_row.m_variable_value.set_field(f);
176 break;
177 default:
178 assert(false);
179 }
180 }
181 }
182
183 return 0;
184 }
185
186