Revert "SERVER-56307 Allow the donor to enter the critical section when the untransferred mods are within a convergence threshold."

This reverts commit f32a3d08fb7128de3c1b43b8478a5e4626101b89.

5 files changed, 7 insertions, 89 deletions

diff --git a/src/mongo/db/s/migration_chunk_cloner_source_legacy.cpp b/src/mongo/db/s/migration_chunk_cloner_source_legacy.cpp
index 863ea9150c4..28377ec41a0 100644
--- a/src/mongo/db/s/migration_chunk_cloner_source_legacy.cpp
+++ b/src/mongo/db/s/migration_chunk_cloner_source_legacy.cpp
@@ -39,13 +39,11 @@
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/dbhelpers.h"
 #include "mongo/db/exec/working_set_common.h"
-#include "mongo/db/index/index_access_method.h"
 #include "mongo/db/index/index_descriptor.h"
 #include "mongo/db/repl/optime.h"
 #include "mongo/db/repl/replication_process.h"
 #include "mongo/db/s/collection_sharding_runtime.h"
 #include "mongo/db/s/migration_source_manager.h"
-#include "mongo/db/s/sharding_runtime_d_params_gen.h"
 #include "mongo/db/s/sharding_statistics.h"
 #include "mongo/db/s/start_chunk_clone_request.h"
 #include "mongo/db/service_context.h"
@@ -879,18 +877,18 @@ MigrationChunkClonerSourceLegacy::_getIndexScanExecutor(
     InternalPlanner::IndexScanOptions scanOption) {
     // Allow multiKey based on the invariant that shard keys must be single-valued. Therefore, any
     // multi-key index prefixed by shard key cannot be multikey over the shard key fields.
-    const IndexDescriptor* shardKeyIdx =
+    const IndexDescriptor* idx =
         collection->getIndexCatalog()->findShardKeyPrefixedIndex(opCtx,
                                                                  _shardKeyPattern.toBSON(),
                                                                  false);  // requireSingleKey
-    if (!shardKeyIdx) {
+    if (!idx) {
         return {ErrorCodes::IndexNotFound,
                 str::stream() << "can't find index with prefix " << _shardKeyPattern.toBSON()
                               << " in storeCurrentLocs for " << _args.getNss().ns()};
     }
 
     // Assume both min and max non-empty, append MinKey's to make them fit chosen index
-    const KeyPattern kp(shardKeyIdx->keyPattern());
+    const KeyPattern kp(idx->keyPattern());
 
     BSONObj min = Helpers::toKeyFormat(kp.extendRangeBound(_args.getMinKey(), false));
     BSONObj max = Helpers::toKeyFormat(kp.extendRangeBound(_args.getMaxKey(), false));
@@ -899,7 +897,7 @@ MigrationChunkClonerSourceLegacy::_getIndexScanExecutor(
     // being queued and will migrate in the 'transferMods' stage.
     return InternalPlanner::indexScan(opCtx,
                                       collection,
-                                      shardKeyIdx,
+                                      idx,
                                       min,
                                       max,
                                       BoundInclusion::kIncludeStartKeyOnly,
@@ -982,20 +980,6 @@ Status MigrationChunkClonerSourceLegacy::_storeCurrentLocs(OperationContext* opC
 
     const uint64_t collectionAverageObjectSize = collection->averageObjectSize(opCtx);
 
-    uint64_t averageObjectIdSize = 0;
-    const uint64_t defaultObjectIdSize = OID::kOIDSize;
-    if (totalRecs > 0) {
-        const auto indexCatalog = collection->getIndexCatalog();
-        const auto idIdx = indexCatalog->findIdIndex(opCtx);
-        if (!idIdx) {
-            return {ErrorCodes::IndexNotFound,
-                    str::stream() << "can't find index '_id' in storeCurrentLocs for "
-                                  << _args.getNss().ns()};
-        }
-        averageObjectIdSize =
-            indexCatalog->getEntry(idIdx)->accessMethod()->getSpaceUsedBytes(opCtx) / totalRecs;
-    }
-
     if (isLargeChunk) {
         return {
             ErrorCodes::ChunkTooBig,
@@ -1008,8 +992,8 @@ Status MigrationChunkClonerSourceLegacy::_storeCurrentLocs(OperationContext* opC
     }
 
     stdx::lock_guard<Latch> lk(_mutex);
-    _averageObjectSizeForCloneLocs = collectionAverageObjectSize + defaultObjectIdSize;
-    _averageObjectIdSize = std::max(averageObjectIdSize, defaultObjectIdSize);
+    _averageObjectSizeForCloneLocs = collectionAverageObjectSize + 12;
+
     return Status::OK();
 }
 
@@ -1123,31 +1107,6 @@ Status MigrationChunkClonerSourceLegacy::_checkRecipientCloningStatus(OperationC
             return Status::OK();
         }
 
-        bool supportsCriticalSectionDuringCatchUp = false;
-        if (auto featureSupportedField =
-                res[StartChunkCloneRequest::kSupportsCriticalSectionDuringCatchUp]) {
-            if (!featureSupportedField.booleanSafe()) {
-                return {ErrorCodes::Error(563070),
-                        str::stream()
-                            << "Illegal value for "
-                            << StartChunkCloneRequest::kSupportsCriticalSectionDuringCatchUp};
-            }
-            supportsCriticalSectionDuringCatchUp = true;
-        }
-
-        if (res["state"].String() == "catchup" && supportsCriticalSectionDuringCatchUp) {
-            int64_t estimatedUntransferredModsSize = _deleted.size() * _averageObjectIdSize +
-                _reload.size() * _averageObjectSizeForCloneLocs;
-            auto estimatedUntransferredChunkPercentage =
-                (std::min(_args.getMaxChunkSizeBytes(), estimatedUntransferredModsSize) * 100) /
-                _args.getMaxChunkSizeBytes();
-            if (estimatedUntransferredChunkPercentage < minCatchUpPercentageBeforeBlockingWrites) {
-                // The recipient is sufficiently caught-up with the writes on the donor.
-                // Block writes, so that it can drain everything.
-                return Status::OK();
-            }
-        }
-
         if (res["state"].String() == "fail") {
             return {ErrorCodes::OperationFailed,
                     str::stream() << "Data transfer error: " << res["errmsg"].str()};
diff --git a/src/mongo/db/s/migration_chunk_cloner_source_legacy.h b/src/mongo/db/s/migration_chunk_cloner_source_legacy.h
index d95d360b0af..9d438d20eb0 100644
--- a/src/mongo/db/s/migration_chunk_cloner_source_legacy.h
+++ b/src/mongo/db/s/migration_chunk_cloner_source_legacy.h
@@ -359,9 +359,6 @@ private:
     // pre-allocation (initial clone).
     uint64_t _averageObjectSizeForCloneLocs{0};
 
-    // The estimated average object _id size during the clone phase.
-    uint64_t _averageObjectIdSize{0};
-
     // Represents all of the requested but not yet fulfilled operations to be tracked, with regards
     // to the chunk being cloned.
     uint64_t _outstandingOperationTrackRequests{0};
diff --git a/src/mongo/db/s/migration_destination_manager.cpp b/src/mongo/db/s/migration_destination_manager.cpp
index 3066f645590..85b980e73eb 100644
--- a/src/mongo/db/s/migration_destination_manager.cpp
+++ b/src/mongo/db/s/migration_destination_manager.cpp
@@ -365,7 +365,6 @@ void MigrationDestinationManager::report(BSONObjBuilder& b,
     b.append("min", _min);
     b.append("max", _max);
     b.append("shardKeyPattern", _shardKeyPattern);
-    b.append(StartChunkCloneRequest::kSupportsCriticalSectionDuringCatchUp, true);
 
     b.append("state", stateToString(_state));
 
@@ -566,24 +565,6 @@ Status MigrationDestinationManager::startCommit(const MigrationSessionId& sessio
 
     stdx::unique_lock<Latch> lock(_mutex);
 
-    const auto convergenceTimeout =
-        Shard::kDefaultConfigCommandTimeout + Shard::kDefaultConfigCommandTimeout / 4;
-
-    // The donor may have started the commit while the recipient is still busy processing
-    // the last batch of mods sent in the catch up phase. Allow some time for synching up.
-    auto deadline = Date_t::now() + convergenceTimeout;
-
-    while (_state == CATCHUP) {
-        if (stdx::cv_status::timeout ==
-            _stateChangedCV.wait_until(lock, deadline.toSystemTimePoint())) {
-            return {ErrorCodes::CommandFailed,
-                    str::stream() << "startCommit timed out waiting for the catch up completion. "
-                                  << "Sender's session is " << sessionId.toString()
-                                  << ". Current session is "
-                                  << (_sessionId ? _sessionId->toString() : "none.")};
-        }
-    }
-
     if (_state != STEADY) {
         return {ErrorCodes::CommandFailed,
                 str::stream() << "Migration startCommit attempted when not in STEADY state."
@@ -609,9 +590,7 @@ Status MigrationDestinationManager::startCommit(const MigrationSessionId& sessio
     _state = COMMIT_START;
     _stateChangedCV.notify_all();
 
-    // Assigning a timeout slightly higher than the one used for network requests to the config
-    // server. Enough time to retry at least once in case of network failures (SERVER-51397).
-    deadline = Date_t::now() + convergenceTimeout;
+    auto const deadline = Date_t::now() + Seconds(30);
     while (_sessionId) {
         if (stdx::cv_status::timeout ==
             _isActiveCV.wait_until(lock, deadline.toSystemTimePoint())) {
@@ -1194,7 +1173,6 @@ void MigrationDestinationManager::_migrateDriver(OperationContext* outerOpCtx) {
             const auto& mods = res.response;
 
             if (mods["size"].number() == 0) {
-                // There are no more pending modifications to be applied. End the catchup phase
                 break;
             }
 
diff --git a/src/mongo/db/s/sharding_runtime_d_params.idl b/src/mongo/db/s/sharding_runtime_d_params.idl
index 76aebc4934f..dbe92c56f81 100644
--- a/src/mongo/db/s/sharding_runtime_d_params.idl
+++ b/src/mongo/db/s/sharding_runtime_d_params.idl
@@ -84,19 +84,6 @@ server_parameters:
         cpp_varname: migrationLockAcquisitionMaxWaitMS
         default: 500
 
-    minCatchUpPercentageBeforeBlockingWrites:
-        description: >-
-          The maximum percentage of untrasferred chunk mods at the end of a catch up iteration
-          that may be deferred to the next phase of the migration protocol
-          (where new writes get blocked).
-        set_at: [startup]
-        cpp_vartype: int
-        cpp_varname: minCatchUpPercentageBeforeBlockingWrites
-        validator:
-          gte: 0
-          lte: 100
-        default: 10
-
     orphanCleanupDelaySecs:
         description: 'How long to wait before starting cleanup of an emigrated chunk range.'
         set_at: [startup, runtime]
diff --git a/src/mongo/db/s/start_chunk_clone_request.h b/src/mongo/db/s/start_chunk_clone_request.h
index b9bf2080def..17cc08f4460 100644
--- a/src/mongo/db/s/start_chunk_clone_request.h
+++ b/src/mongo/db/s/start_chunk_clone_request.h
@@ -49,9 +49,6 @@ class StatusWith;
  */
 class StartChunkCloneRequest {
 public:
-    static constexpr auto kSupportsCriticalSectionDuringCatchUp =
-        "supportsCriticalSectionDuringCatchUp"_sd;
-
     /**
      * Parses the input command and produces a request corresponding to its arguments.
      */