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
|
/**
* Copyright (C) 2013-2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/exec/plan_stats.h"
#include "mongo/db/query/canonical_query.h"
#include "mongo/db/query/explain_common.h"
#include "mongo/db/query/plan_executor.h"
#include "mongo/db/query/query_planner_params.h"
#include "mongo/db/query/query_solution.h"
namespace mongo {
class Collection;
class OperationContext;
/**
* A container for the summary statistics that the profiler, slow query log, and
* other non-explain debug mechanisms may want to collect.
*/
struct PlanSummaryStats {
PlanSummaryStats() : nReturned(0),
totalKeysExamined(0),
totalDocsExamined(0),
executionTimeMillis(0),
isIdhack(false),
hasSortStage(false) { }
// The number of results returned by the plan.
size_t nReturned;
// The total number of index keys examined by the plan.
size_t totalKeysExamined;
// The total number of documents examined by the plan.
size_t totalDocsExamined;
// The number of milliseconds spent inside the root stage's work() method.
long long executionTimeMillis;
// Did this plan use the fast path for key-value retrievals on the _id index?
bool isIdhack;
// Did this plan use an in-memory sort stage?
bool hasSortStage;
};
/**
* Namespace for the collection of static methods used to generate explain information.
*/
class Explain {
public:
/**
* Get explain BSON for the execution stages contained by 'exec'. Use this function if you
* have a PlanExecutor and want to convert it into a human readable explain format. Any
* operation which has a query component (e.g. find, update, group) can be explained via
* this function.
*
* The explain information is extracted from 'exec' and added to the out-parameter 'out'.
*
* The explain information is generated with the level of detail specified by 'verbosity'.
*
* Does not take ownership of its arguments.
*
* If there is an error during the execution of the query, the error message and code are
* added to the "executionStats" section of the explain.
*/
static void explainStages(PlanExecutor* exec,
ExplainCommon::Verbosity verbosity,
BSONObjBuilder* out);
/**
* Converts the stats tree 'stats' into a corresponding BSON object containing
* explain information.
*
* Generates the BSON stats at a verbosity specified by 'verbosity'. Defaults
* to execution stats verbosity.
*/
static BSONObj statsToBSON(const PlanStageStats& stats,
ExplainCommon::Verbosity verbosity = ExplainCommon::EXEC_STATS);
/**
* This version of stats tree to BSON conversion returns the result through the
* out-parameter 'bob' rather than returning a BSONObj.
*
* Generates the BSON stats at a verbosity specified by 'verbosity'. Defaults
* to execution stats verbosity.
*/
static void statsToBSON(const PlanStageStats& stats,
BSONObjBuilder* bob,
ExplainCommon::Verbosity verbosity = ExplainCommon::EXEC_STATS);
/**
* Returns a short plan summary std::string describing the leaves of the query plan.
*/
static std::string getPlanSummary(PlanExecutor* exec);
static std::string getPlanSummary(PlanStage* root);
/**
* Fills out 'statsOut' with summary stats using the execution tree contained
* in 'exec'.
*
* The summary stats are consumed by debug mechanisms such as the profiler and
* the slow query log.
*
* This is a lightweight alternative for explainStages(...) above which is useful
* when operations want to request debug information without doing all the work
* to generate a full explain.
*
* Does not take ownership of its arguments.
*/
static void getSummaryStats(PlanExecutor* exec, PlanSummaryStats* statsOut);
private:
/**
* Private helper that does the heavy-lifting for the public statsToBSON(...) functions
* declared above.
*
* Not used except as a helper to the public statsToBSON(...) functions.
*/
static void statsToBSON(const PlanStageStats& stats,
ExplainCommon::Verbosity verbosity,
BSONObjBuilder* bob,
BSONObjBuilder* topLevelBob);
/**
* Adds the 'queryPlanner' explain section to the BSON object being built
* by 'out'.
*
* This is a helper for generating explain BSON. It is used by explainStages(...).
*
* @param exec -- the stage tree for the operation being explained.
* @param winnerStats -- the stats tree for the winning plan.
* @param rejectedStats -- an array of stats trees, one per rejected plan
*/
static void generatePlannerInfo(PlanExecutor* exec,
PlanStageStats* winnerStats,
const std::vector<PlanStageStats*>& rejectedStats,
BSONObjBuilder* out);
/**
* Generates the execution stats section for the stats tree 'stats',
* adding the resulting BSON to 'out'.
*
* The 'totalTimeMillis' value passed here will be added to the top level of
* the execution stats section, but will not affect the reporting of timing for
* individual stages. If 'totalTimeMillis' is not specified, then the default
* value of -1 indicates that we should only use the approximate timing information
* collected by the stages.
*
* Stats are generated at the verbosity specified by 'verbosity'.
*
* This is a helper for generating explain BSON. It is used by explainStages(...).
*/
static void generateExecStats(PlanStageStats* stats,
ExplainCommon::Verbosity verbosity,
BSONObjBuilder* out,
long long totalTimeMillis = -1);
/**
* Adds the 'serverInfo' explain section to the BSON object being build
* by 'out'.
*
* This is a helper for generating explain BSON. It is used by explainStages(...).
*/
static void generateServerInfo(BSONObjBuilder* out);
};
} // namespace
|
