SERVER-19758 add support for "executionStats" and "allPlansExecution" to agg explain

Like other explainable commands, aggregate can now be
explained using the explain command, e.g.
db.runCommand({explain: {aggregate: ...}, verbosity:
"executionStats"}). The existing explain:true flag
corresponds to "queryPlanner" mode and is still supported.
However, explain:true cannot be specified when explaining
aggregate via the explain command.

Additional execution information is provided only in the
$cursor section of the aggregation explain output. Having
aggregation stages themselves track and report execution
info is further work.

1 files changed, 0 insertions, 76 deletions

diff --git a/src/mongo/db/query/explain_common.h b/src/mongo/db/query/explain_common.h
deleted file mode 100644
index 750f207a2a5..00000000000
--- a/src/mongo/db/query/explain_common.h
+++ /dev/null
@@ -1,76 +0,0 @@
-/**
- *    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/base/status.h"
-#include "mongo/bson/bsonobj.h"
-
-namespace mongo {
-
-/**
- * Utilities used for explain implementations on both mongod and mongos.
- */
-class ExplainCommon {
-public:
-    /**
-     * The various supported verbosity levels for explain. The order is
-     * significant: the enum values are assigned in order of increasing verbosity.
-     */
-    enum Verbosity {
-        // At all verbosities greater than or equal to QUERY_PLANNER, we display information
-        // about the plan selected and alternate rejected plans. Does not include any execution-
-        // related info. String alias is "queryPlanner".
-        QUERY_PLANNER = 0,
-
-        // At all verbosities greater than or equal to EXEC_STATS, we display a section of
-        // output containing both overall execution stats, and stats per stage in the
-        // execution tree. String alias is "execStats".
-        EXEC_STATS = 1,
-
-        // At this verbosity level, we generate the execution stats for each rejected plan as
-        // well as the winning plan. String alias is "allPlansExecution".
-        EXEC_ALL_PLANS = 2,
-    };
-
-    /**
-     * Converts an explain verbosity to its string representation.
-     */
-    static const char* verbosityString(ExplainCommon::Verbosity verbosity);
-
-    /**
-     * Does some basic validation of the command BSON, and retrieves the explain verbosity.
-     *
-     * Returns a non-OK status if parsing fails.
-     *
-     * On success, populates "verbosity".
-     */
-    static Status parseCmdBSON(const BSONObj& cmdObj, ExplainCommon::Verbosity* verbosity);
-};
-
-}  // namespace