Revert "SERVER-24817 Make ShardLocal wait for writes it performed when doing majority reads"

This reverts commit 88daeb804d093011144cb5e3a0295aa9eb89c42b.

2 files changed, 8 insertions, 53 deletions

diff --git a/src/mongo/s/client/shard_local.cpp b/src/mongo/s/client/shard_local.cpp
index b6789ecb170..dcf6db33205 100644
--- a/src/mongo/s/client/shard_local.cpp
+++ b/src/mongo/s/client/shard_local.cpp
@@ -37,14 +37,12 @@
 #include "mongo/client/remote_command_targeter.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/dbdirectclient.h"
-#include "mongo/db/repl/read_concern_response.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/repl/replica_set_config.h"
 #include "mongo/db/repl/replication_coordinator_global.h"
 #include "mongo/rpc/get_status_from_command_result.h"
 #include "mongo/rpc/unique_message.h"
 #include "mongo/util/log.h"
-#include "mongo/util/scopeguard.h"
 
 namespace mongo {
 
@@ -96,29 +94,10 @@ bool ShardLocal::isRetriableError(ErrorCodes::Error code, RetryPolicy options) {
     }
 }
 
-void ShardLocal::_updateLastOpTimeFromClient(OperationContext* txn) {
-    repl::OpTime lastOpTimeFromClient =
-        repl::ReplClientInfo::forClient(txn->getClient()).getLastOp();
-    if (lastOpTimeFromClient.isNull()) {
-        return;
-    }
-
-    stdx::lock_guard<stdx::mutex> lk(_mutex);
-    invariant(lastOpTimeFromClient >= _lastOpTime);
-    _lastOpTime = lastOpTimeFromClient;
-}
-
-repl::OpTime ShardLocal::_getLastOpTime() {
-    stdx::lock_guard<stdx::mutex> lk(_mutex);
-    return _lastOpTime;
-}
-
 StatusWith<Shard::CommandResponse> ShardLocal::_runCommand(OperationContext* txn,
                                                            const ReadPreferenceSetting& unused,
                                                            const std::string& dbName,
                                                            const BSONObj& cmdObj) {
-    ON_BLOCK_EXIT([this, &txn] { _updateLastOpTimeFromClient(txn); });
-
     try {
         DBDirectClient client(txn);
         rpc::UniqueReply commandResponse = client.runCommandWithMetadata(
@@ -155,21 +134,16 @@ StatusWith<Shard::QueryResponse> ShardLocal::_exhaustiveFindOnConfig(
         // Set up operation context with majority read snapshot so correct optime can be retrieved.
         Status status = txn->recoveryUnit()->setReadFromMajorityCommittedSnapshot();
 
-        // Wait for any writes performed by this ShardLocal instance to be committed and visible.
-        auto readConcernResponse = replCoord->waitUntilOpTime(
-            txn, repl::ReadConcernArgs{_getLastOpTime(), readConcernLevel});
-        if (!readConcernResponse.getStatus().isOK()) {
-            if (readConcernResponse.getStatus() == ErrorCodes::ShutdownInProgress ||
-                ErrorCodes::isInterruption(readConcernResponse.getStatus().code())) {
-                return readConcernResponse.getStatus();
-            }
-            fassertStatusOK(40188, readConcernResponse.getStatus());
+        // Wait until a snapshot is available.
+        while (status == ErrorCodes::ReadConcernMajorityNotAvailableYet) {
+            LOG(1) << "Waiting for ReadFromMajorityCommittedSnapshot to become available";
+            replCoord->waitUntilSnapshotCommitted(txn, SnapshotName::min());
+            status = txn->recoveryUnit()->setReadFromMajorityCommittedSnapshot();
         }
 
-        // Inform the storage engine to read from the committed snapshot for the rest of this
-        // operation.
-        status = txn->recoveryUnit()->setReadFromMajorityCommittedSnapshot();
-        fassertStatusOK(40189, status);
+        if (!status.isOK()) {
+            return status;
+        }
     } else {
         invariant(readConcernLevel == repl::ReadConcernLevel::kLocalReadConcern);
     }
diff --git a/src/mongo/s/client/shard_local.h b/src/mongo/s/client/shard_local.h
index 1c65015b78e..b39aba621d0 100644
--- a/src/mongo/s/client/shard_local.h
+++ b/src/mongo/s/client/shard_local.h
@@ -30,9 +30,7 @@
 
 #include "mongo/base/disallow_copying.h"
 #include "mongo/client/dbclientinterface.h"
-#include "mongo/db/repl/optime.h"
 #include "mongo/s/client/shard.h"
-#include "mongo/stdx/mutex.h"
 
 namespace mongo {
 
@@ -77,23 +75,6 @@ private:
         const BSONObj& query,
         const BSONObj& sort,
         boost::optional<long long> limit) final;
-
-    /**
-     * Checks if an OpTime was set on the current Client (ie if the current operation performed a
-     * write) and if so updates _lastOpTime to the OpTime from the write that was just performed.
-     */
-    void _updateLastOpTimeFromClient(OperationContext* txn);
-
-    repl::OpTime _getLastOpTime();
-
-    // Guards _lastOpTime below.
-    stdx::mutex _mutex;
-
-    // Stores the optime that was generated by the last operation to perform a write that was run
-    // through _runCommand.  Used in _exhaustiveFindOnConfig for waiting for that optime to be
-    // committed so that readConcern majority reads will read the writes that were performed without
-    // a w:majority write concern.
-    repl::OpTime _lastOpTime{};
 };
 
 }  // namespace mongo