1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/*
Copyright (c) 2011, 2013 Monty Program Ab.
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 */
#ifndef MY_APC_STANDALONE
#include "sql_class.h"
#endif
/* For standalone testing of APC system, see unittest/sql/my_apc-t.cc */
/*
Initialize the target.
@note
Initialization must be done prior to enabling/disabling the target, or making
any call requests to it.
Initial state after initialization is 'disabled'.
*/
void Apc_target::init(mysql_mutex_t *target_mutex)
{
DBUG_ASSERT(!enabled);
LOCK_thd_data_ptr= target_mutex;
#ifndef DBUG_OFF
n_calls_processed= 0;
#endif
}
/* [internal] Put request qe into the request list */
void Apc_target::enqueue_request(Call_request *qe)
{
mysql_mutex_assert_owner(LOCK_thd_data_ptr);
if (apc_calls)
{
Call_request *after= apc_calls->prev;
qe->next= apc_calls;
apc_calls->prev= qe;
qe->prev= after;
after->next= qe;
}
else
{
apc_calls= qe;
qe->next= qe->prev= qe;
}
}
/*
[internal] Remove request qe from the request queue.
The request is not necessarily first in the queue.
*/
void Apc_target::dequeue_request(Call_request *qe)
{
mysql_mutex_assert_owner(LOCK_thd_data_ptr);
if (apc_calls == qe)
{
if ((apc_calls= apc_calls->next) == qe)
{
apc_calls= NULL;
}
}
qe->prev->next= qe->next;
qe->next->prev= qe->prev;
}
#ifdef HAVE_PSI_INTERFACE
/* One key for all conds */
PSI_cond_key key_show_explain_request_COND;
static PSI_cond_info show_explain_psi_conds[]=
{
{ &key_show_explain_request_COND, "show_explain", 0 /* not using PSI_FLAG_GLOBAL*/ }
};
void init_show_explain_psi_keys(void)
{
if (PSI_server == NULL)
return;
PSI_server->register_cond("sql", show_explain_psi_conds,
array_elements(show_explain_psi_conds));
}
#endif
/*
Make an APC (Async Procedure Call) to another thread.
@detail
Make an APC call: schedule it for execution and wait until the target
thread has executed it.
- The caller is responsible for making sure he's not posting request
to the thread he's calling this function from.
- The caller must have locked target_mutex. The function will release it.
@retval FALSE - Ok, the call has been made
@retval TRUE - Call wasnt made (either the target is in disabled state or
timeout occurred)
*/
bool Apc_target::make_apc_call(THD *caller_thd, Apc_call *call,
int timeout_sec, bool *timed_out)
{
bool res= TRUE;
*timed_out= FALSE;
if (enabled)
{
/* Create and post the request */
Call_request apc_request;
apc_request.call= call;
apc_request.processed= FALSE;
mysql_cond_init(key_show_explain_request_COND, &apc_request.COND_request,
NULL);
enqueue_request(&apc_request);
apc_request.what="enqueued by make_apc_call";
struct timespec abstime;
const int timeout= timeout_sec;
set_timespec(abstime, timeout);
int wait_res= 0;
PSI_stage_info old_stage;
caller_thd->ENTER_COND(&apc_request.COND_request, LOCK_thd_data_ptr,
&stage_show_explain, &old_stage);
/* todo: how about processing other errors here? */
while (!apc_request.processed && (wait_res != ETIMEDOUT))
{
/* We own LOCK_thd_data_ptr */
wait_res= mysql_cond_timedwait(&apc_request.COND_request,
LOCK_thd_data_ptr, &abstime);
// &apc_request.LOCK_request, &abstime);
if (caller_thd->killed)
break;
}
if (!apc_request.processed)
{
/*
The wait has timed out, or this thread was KILLed.
Remove the request from the queue (ok to do because we own
LOCK_thd_data_ptr)
*/
apc_request.processed= TRUE;
dequeue_request(&apc_request);
*timed_out= TRUE;
res= TRUE;
}
else
{
/* Request was successfully executed and dequeued by the target thread */
res= FALSE;
}
/*
exit_cond() will call mysql_mutex_unlock(LOCK_thd_data_ptr) for us:
*/
caller_thd->EXIT_COND(&old_stage);
/* Destroy all APC request data */
mysql_cond_destroy(&apc_request.COND_request);
}
else
{
mysql_mutex_unlock(LOCK_thd_data_ptr);
}
return res;
}
/*
Process all APC requests.
This should be called periodically by the APC target thread.
*/
void Apc_target::process_apc_requests()
{
while (1)
{
Call_request *request;
mysql_mutex_lock(LOCK_thd_data_ptr);
if (!(request= get_first_in_queue()))
{
/* No requests in the queue */
mysql_mutex_unlock(LOCK_thd_data_ptr);
break;
}
/*
Remove the request from the queue (we're holding queue lock so we can be
sure that request owner won't try to remove it)
*/
request->what="dequeued by process_apc_requests";
dequeue_request(request);
request->processed= TRUE;
request->call->call_in_target_thread();
request->what="func called by process_apc_requests";
#ifndef DBUG_OFF
n_calls_processed++;
#endif
mysql_cond_signal(&request->COND_request);
mysql_mutex_unlock(LOCK_thd_data_ptr);
}
}
|
