SERVER-42134 Deprecate certain mapReduce parameters

3 files changed, 30 insertions, 4 deletions

diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 74ec1dbfdbe..244acfbd221 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -72,6 +72,7 @@
 #include "mongo/s/stale_exception.h"
 #include "mongo/scripting/engine.h"
 #include "mongo/stdx/mutex.h"
+#include "mongo/util/debug_util.h"
 #include "mongo/util/log.h"
 #include "mongo/util/scopeguard.h"
 #include "mongo/util/str.h"
@@ -92,6 +93,8 @@ namespace dps = ::mongo::dotted_path_support;
 namespace mr {
 namespace {
 
+Rarely mapParamsDeprecationSampler;  // Used to occasionally log deprecation messages.
+
 /**
  * Runs a count against the namespace specified by 'ns'. If the caller holds the global write lock,
  * then this function does not acquire any additional locks.
@@ -456,8 +459,14 @@ Config::Config(const string& _dbname, const BSONObj& cmdObj) {
         if (cmdObj["finalize"].type() && cmdObj["finalize"].trueValue())
             finalizer.reset(new JSFinalizer(cmdObj["finalize"]));
 
-        if (cmdObj["mapparams"].type() == Array) {
-            mapParams = cmdObj["mapparams"].embeddedObjectUserCheck().getOwned();
+        // DEPRECATED
+        if (auto mapParamsElem = cmdObj["mapparams"]) {
+            if (mapParamsDeprecationSampler.tick()) {
+                warning() << "The mapparams option to MapReduce is deprecated.";
+            }
+            if (mapParamsElem.type() == Array) {
+                mapParams = mapParamsElem.embeddedObjectUserCheck().getOwned();
+            }
         }
     }
 
diff --git a/src/mongo/db/commands/mr_common.cpp b/src/mongo/db/commands/mr_common.cpp
index ad82a5d190b..90ebddcd6e6 100644
--- a/src/mongo/db/commands/mr_common.cpp
+++ b/src/mongo/db/commands/mr_common.cpp
@@ -27,6 +27,8 @@
  *    it in the license file.
  */
 
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
+
 #include "mongo/db/commands/mr_common.h"
 
 #include <string>
@@ -38,11 +40,17 @@
 #include "mongo/db/catalog/document_validation.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/jsobj.h"
+#include "mongo/util/log.h"
 #include "mongo/util/str.h"
 
 namespace mongo {
 
 namespace mr {
+
+namespace {
+Rarely nonAtomicDeprecationSampler;  // Used to occasionally log deprecation messages.
+}  // namespace
+
 OutputOptions parseOutputOptions(const std::string& dbname, const BSONObj& cmdObj) {
     OutputOptions outputOptions;
 
@@ -76,14 +84,16 @@ OutputOptions parseOutputOptions(const std::string& dbname, const BSONObj& cmdOb
         if (o.hasElement("db")) {
             outputOptions.outDB = o["db"].String();
         }
-
         if (o.hasElement("nonAtomic")) {
             outputOptions.outNonAtomic = o["nonAtomic"].Bool();
-            if (outputOptions.outNonAtomic)
+            if (outputOptions.outNonAtomic) {
                 uassert(15895,
                         "nonAtomic option cannot be used with this output type",
                         (outputOptions.outType == OutputType::kReduce ||
                          outputOptions.outType == OutputType::kMerge));
+            } else if (nonAtomicDeprecationSampler.tick()) {
+                warning() << "Setting out.nonAtomic to false in MapReduce is deprecated.";
+            }
         }
     } else {
         uasserted(13606, "'out' has to be a string or an object");
diff --git a/src/mongo/s/commands/cluster_map_reduce.cpp b/src/mongo/s/commands/cluster_map_reduce.cpp
index dd74ef1e6c7..af3d8274601 100644
--- a/src/mongo/s/commands/cluster_map_reduce.cpp
+++ b/src/mongo/s/commands/cluster_map_reduce.cpp
@@ -52,6 +52,10 @@ namespace mongo {
 const Milliseconds kNoDistLockTimeout(-1);
 
 AtomicWord<unsigned> jobNumber;
+namespace {
+// Used to rarely log deprecation messages.
+Rarely shardedOutputDeprecationSampler;
+}  // namespace
 
 /**
  * Generates a unique name for the temporary M/R output collection.
@@ -221,6 +225,9 @@ bool runMapReduce(OperationContext* opCtx,
     if (outElmt.type() == Object) {
         // Check if there is a custom output
         BSONObj customOut = outElmt.embeddedObject();
+        if (customOut.hasField("sharded") && shardedOutputDeprecationSampler.tick()) {
+            warning() << "the out.sharded option to mapReduce is deprecated.";
+        }
         shardedOutput = customOut.getBoolField("sharded");
 
         if (customOut.hasField("inline")) {