Revert "SERVER-33455 SERVER-33452 - Add history to the chunk type and update move/split/merge methods."

This reverts commit 5b42a86b74380953db29455dc68e133166c81005.

22 files changed, 43 insertions, 548 deletions

diff --git a/src/mongo/db/s/config/configsvr_commit_chunk_migration_command.cpp b/src/mongo/db/s/config/configsvr_commit_chunk_migration_command.cpp
index 5756821d11e..28119fe682e 100644
--- a/src/mongo/db/s/config/configsvr_commit_chunk_migration_command.cpp
+++ b/src/mongo/db/s/config/configsvr_commit_chunk_migration_command.cpp
@@ -134,8 +134,7 @@ public:
             commitRequest.getControlChunk(),
             commitRequest.getCollectionEpoch(),
             commitRequest.getFromShard(),
-            commitRequest.getToShard(),
-            commitRequest.getValidAfter());
+            commitRequest.getToShard());
         if (!response.isOK()) {
             return CommandHelpers::appendCommandStatus(result, response.getStatus());
         }
diff --git a/src/mongo/db/s/config/configsvr_merge_chunk_command.cpp b/src/mongo/db/s/config/configsvr_merge_chunk_command.cpp
index 91c7fe9de31..74d11ef2eb5 100644
--- a/src/mongo/db/s/config/configsvr_merge_chunk_command.cpp
+++ b/src/mongo/db/s/config/configsvr_merge_chunk_command.cpp
@@ -114,8 +114,7 @@ public:
                                                                  parsedRequest.getNamespace(),
                                                                  parsedRequest.getEpoch(),
                                                                  parsedRequest.getChunkBoundaries(),
-                                                                 parsedRequest.getShardName(),
-                                                                 parsedRequest.getValidAfter());
+                                                                 parsedRequest.getShardName());
 
         if (!mergeChunkResult.isOK()) {
             return CommandHelpers::appendCommandStatus(result, mergeChunkResult);
diff --git a/src/mongo/db/s/config/sharding_catalog_manager.h b/src/mongo/db/s/config/sharding_catalog_manager.h
index a244f701133..786b862f7ee 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager.h
+++ b/src/mongo/db/s/config/sharding_catalog_manager.h
@@ -171,20 +171,15 @@ public:
     /**
      * Updates metadata in the config.chunks collection so the chunks with given boundaries are seen
      * merged into a single larger chunk.
-     * If 'validAfter' is not set, this means the commit request came from an older server version,
-     * which is not history-aware.
      */
     Status commitChunkMerge(OperationContext* opCtx,
                             const NamespaceString& nss,
                             const OID& requestEpoch,
                             const std::vector<BSONObj>& chunkBoundaries,
-                            const std::string& shardName,
-                            const boost::optional<Timestamp>& validAfter);
+                            const std::string& shardName);
 
     /**
      * Updates metadata in config.chunks collection to show the given chunk in its new shard.
-     * If 'validAfter' is not set, this means the commit request came from an older server version,
-     * which is not history-aware.
      */
     StatusWith<BSONObj> commitChunkMigration(OperationContext* opCtx,
                                              const NamespaceString& nss,
@@ -192,8 +187,7 @@ public:
                                              const boost::optional<ChunkType>& controlChunk,
                                              const OID& collectionEpoch,
                                              const ShardId& fromShard,
-                                             const ShardId& toShard,
-                                             const boost::optional<Timestamp>& validAfter);
+                                             const ShardId& toShard);
 
     //
     // Database Operations
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp
index c4fc7ca563e..ea34e097844 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp
@@ -70,8 +70,7 @@ void appendShortVersion(BufBuilder* b, const ChunkType& chunk) {
 }
 
 BSONArray buildMergeChunksTransactionUpdates(const std::vector<ChunkType>& chunksToMerge,
-                                             const ChunkVersion& mergeVersion,
-                                             const boost::optional<Timestamp>& validAfter) {
+                                             const ChunkVersion& mergeVersion) {
     BSONArrayBuilder updates;
 
     // Build an update operation to expand the first chunk into the newly merged chunk
@@ -88,13 +87,6 @@ BSONArray buildMergeChunksTransactionUpdates(const std::vector<ChunkType>& chunk
         // fill in additional details for sending through transaction
         mergedChunk.setVersion(mergeVersion);
 
-        // Clear the chunk history
-        std::vector<ChunkHistory> history;
-        if (validAfter) {
-            history.emplace_back(ChunkHistory(validAfter.get(), mergedChunk.getShard()));
-        }
-        mergedChunk.setHistory(std::move(history));
-
         // add the new chunk information as the update object
         op.append("o", mergedChunk.toConfigBSON());
 
@@ -196,7 +188,6 @@ BSONObj makeCommitChunkTransactionCommand(const NamespaceString& nss,
         n.append(ChunkType::min(), migratedChunk.getMin());
         n.append(ChunkType::max(), migratedChunk.getMax());
         n.append(ChunkType::shard(), toShard);
-        migratedChunk.addHistoryToBSON(n);
         n.done();
 
         BSONObjBuilder q(op.subobjStart("o2"));
@@ -284,32 +275,6 @@ Status ShardingCatalogManager::commitChunkSplit(OperationContext* opCtx,
         return {ErrorCodes::StaleEpoch, errmsg};
     }
 
-    // Find the chunk history.
-    auto findHistory = Grid::get(opCtx)->shardRegistry()->getConfigShard()->exhaustiveFindOnConfig(
-        opCtx,
-        ReadPreferenceSetting{ReadPreference::PrimaryOnly},
-        repl::ReadConcernLevel::kLocalReadConcern,
-        ChunkType::ConfigNS,
-        BSON(ChunkType::name << ChunkType::genID(nss, range.getMin())),
-        BSONObj(),
-        1);
-    if (!findHistory.isOK()) {
-        return findHistory.getStatus();
-    }
-
-    const auto origChunks = std::move(findHistory.getValue().docs);
-    if (origChunks.size() != 1) {
-        return {ErrorCodes::IncompatibleShardingMetadata,
-                str::stream() << "Tried to find the chunk history for '"
-                              << ChunkType::genID(nss, range.getMin())
-                              << ", but found no chunks"};
-    }
-
-    const auto origChunk = ChunkType::fromConfigBSON(origChunks.front());
-    if (!origChunk.isOK()) {
-        return origChunk.getStatus();
-    }
-
     std::vector<ChunkType> newChunks;
 
     ChunkVersion currentMaxVersion = collVersion;
@@ -371,7 +336,6 @@ Status ShardingCatalogManager::commitChunkSplit(OperationContext* opCtx,
         n.append(ChunkType::min(), startKey);
         n.append(ChunkType::max(), endKey);
         n.append(ChunkType::shard(), shardName);
-        origChunk.getValue().addHistoryToBSON(n);
         n.done();
 
         // add the chunk's _id as the query part of the update statement
@@ -467,8 +431,7 @@ Status ShardingCatalogManager::commitChunkMerge(OperationContext* opCtx,
                                                 const NamespaceString& nss,
                                                 const OID& requestEpoch,
                                                 const std::vector<BSONObj>& chunkBoundaries,
-                                                const std::string& shardName,
-                                                const boost::optional<Timestamp>& validAfter) {
+                                                const std::string& shardName) {
     // This method must never be called with empty chunks to merge
     invariant(!chunkBoundaries.empty());
 
@@ -537,7 +500,7 @@ Status ShardingCatalogManager::commitChunkMerge(OperationContext* opCtx,
     ChunkVersion mergeVersion = collVersion;
     mergeVersion.incMinor();
 
-    auto updates = buildMergeChunksTransactionUpdates(chunksToMerge, mergeVersion, validAfter);
+    auto updates = buildMergeChunksTransactionUpdates(chunksToMerge, mergeVersion);
     auto preCond = buildMergeChunksTransactionPrecond(chunksToMerge, collVersion);
 
     // apply the batch of updates to local metadata
@@ -579,8 +542,7 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
     const boost::optional<ChunkType>& controlChunk,
     const OID& collectionEpoch,
     const ShardId& fromShard,
-    const ShardId& toShard,
-    const boost::optional<Timestamp>& validAfter) {
+    const ShardId& toShard) {
 
     auto const configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
 
@@ -662,65 +624,12 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
         }
     }
 
-    // Find the chunk history.
-    auto findHistory = configShard->exhaustiveFindOnConfig(
-        opCtx,
-        ReadPreferenceSetting{ReadPreference::PrimaryOnly},
-        repl::ReadConcernLevel::kLocalReadConcern,
-        ChunkType::ConfigNS,
-        BSON(ChunkType::name << ChunkType::genID(nss, migratedChunk.getMin())),
-        BSONObj(),
-        1);
-    if (!findHistory.isOK()) {
-        return findHistory.getStatus();
-    }
-
-    const auto origChunks = std::move(findHistory.getValue().docs);
-    if (origChunks.size() != 1) {
-        return {ErrorCodes::IncompatibleShardingMetadata,
-                str::stream() << "Tried to find the chunk history for '"
-                              << ChunkType::genID(nss, migratedChunk.getMin())
-                              << ", but found no chunks"};
-    }
-
-    const auto origChunk = ChunkType::fromConfigBSON(origChunks.front());
-    if (!origChunk.isOK()) {
-        return origChunk.getStatus();
-    }
-
     // Generate the new versions of migratedChunk and controlChunk. Migrating chunk's minor version
     // will be 0.
     ChunkType newMigratedChunk = migratedChunk;
     newMigratedChunk.setVersion(ChunkVersion(
         currentCollectionVersion.majorVersion() + 1, 0, currentCollectionVersion.epoch()));
 
-    // Copy the complete history.
-    auto newHistory = origChunk.getValue().getHistory();
-    const int kHistorySecs = 10;
-
-    // Update the history of the migrated chunk.
-    if (validAfter) {
-        // Drop the history that is too old (10 seconds of history for now).
-        // TODO SERVER-33831 to update the old history removal policy.
-        while (!newHistory.empty() &&
-               newHistory.back().getValidAfter().getSecs() + kHistorySecs <
-                   validAfter.get().getSecs()) {
-            newHistory.pop_back();
-        }
-
-        if (!newHistory.empty() && newHistory.front().getValidAfter() >= validAfter.get()) {
-            return {ErrorCodes::IncompatibleShardingMetadata,
-                    str::stream() << "The chunk history for '"
-                                  << ChunkType::genID(nss, migratedChunk.getMin())
-                                  << " is corrupted. The last validAfter "
-                                  << newHistory.back().getValidAfter().toString()
-                                  << " is greater or equal to the new validAfter "
-                                  << validAfter.get().toString()};
-        }
-        newHistory.emplace(newHistory.begin(), ChunkHistory(validAfter.get(), toShard));
-    }
-    newMigratedChunk.setHistory(std::move(newHistory));
-
     // Control chunk's minor version will be 1 (if control chunk is present).
     boost::optional<ChunkType> newControlChunk = boost::none;
     if (controlChunk) {
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_collection_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_collection_operations.cpp
index 802faba9f97..e990e35f7dd 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_collection_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_collection_operations.cpp
@@ -44,7 +44,6 @@
 #include "mongo/db/catalog/collection_options.h"
 #include "mongo/db/client.h"
 #include "mongo/db/commands.h"
-#include "mongo/db/logical_clock.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/query/collation/collator_factory_interface.h"
@@ -275,8 +274,6 @@ ChunkVersion ShardingCatalogManager::_createFirstChunks(OperationContext* opCtx,
     log() << "going to create " << splitPoints.size() + 1 << " chunk(s) for: " << nss
           << " using new epoch " << version.epoch();
 
-    const auto validAfter = LogicalClock::get(opCtx)->getClusterTime().asTimestamp();
-
     for (unsigned i = 0; i <= splitPoints.size(); i++) {
         const BSONObj min = (i == 0) ? keyPattern.globalMin() : splitPoints[i - 1];
         const BSONObj max = (i < splitPoints.size()) ? splitPoints[i] : keyPattern.globalMax();
@@ -293,10 +290,6 @@ ChunkVersion ShardingCatalogManager::_createFirstChunks(OperationContext* opCtx,
         chunk.setMax(max);
         chunk.setShard(shardIds[i % shardIds.size()]);
         chunk.setVersion(version);
-        // TODO SERVER-33781 write history only when FCV4.0 config.
-        std::vector<ChunkHistory> initialHistory;
-        initialHistory.emplace_back(ChunkHistory(validAfter, shardIds[i % shardIds.size()]));
-        chunk.setHistory(std::move(initialHistory));
 
         uassertStatusOK(Grid::get(opCtx)->catalogClient()->insertConfigDocument(
             opCtx,
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp
index dd1357e8b4a..76340441d2c 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp
@@ -64,7 +64,6 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandWithCtl) {
     chunk0.setNS(kNamespace);
     chunk0.setVersion(origVersion);
     chunk0.setShard(shard0.getName());
-    chunk0.setHistory({ChunkHistory(Timestamp(100, 0), ShardId("shardX"))});
 
     // apportion
     auto chunkMin = BSON("a" << 1);
@@ -87,8 +86,6 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandWithCtl) {
     ChunkType const& chunk0cref = chunk0;
     ChunkType const& chunk1cref = chunk1;
 
-    Timestamp validAfter{101, 0};
-
     StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
                                          ->commitChunkMigration(operationContext(),
                                                                 chunk0.getNS(),
@@ -96,8 +93,7 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandWithCtl) {
                                                                 chunk1cref,
                                                                 origVersion.epoch(),
                                                                 ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
+                                                                ShardId(shard1.getName()));
 
     ASSERT_OK(resultBSON.getStatus());
 
@@ -115,9 +111,6 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandWithCtl) {
     auto chunkDoc0 = uassertStatusOK(getChunkDoc(operationContext(), chunkMin));
     ASSERT_EQ("shard1", chunkDoc0.getShard().toString());
     ASSERT_EQ(mver.getValue(), chunkDoc0.getVersion());
-    // The history should be updated.
-    ASSERT_EQ(2UL, chunkDoc0.getHistory().size());
-    ASSERT_EQ(validAfter, chunkDoc0.getHistory().front().getValidAfter());
 
     auto chunkDoc1 = uassertStatusOK(getChunkDoc(operationContext(), chunkMax));
     ASSERT_EQ("shard0", chunkDoc1.getShard().toString());
@@ -143,7 +136,6 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtl) {
     chunk0.setNS(kNamespace);
     chunk0.setVersion(origVersion);
     chunk0.setShard(shard0.getName());
-    chunk0.setHistory({ChunkHistory(Timestamp(100, 0), ShardId("shardX"))});
 
     // apportion
     auto chunkMin = BSON("a" << 1);
@@ -153,8 +145,6 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtl) {
 
     setupChunks({chunk0}).transitional_ignore();
 
-    Timestamp validAfter{101, 0};
-
     StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
                                          ->commitChunkMigration(operationContext(),
                                                                 chunk0.getNS(),
@@ -162,8 +152,7 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtl) {
                                                                 boost::none,
                                                                 origVersion.epoch(),
                                                                 ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
+                                                                ShardId(shard1.getName()));
 
     ASSERT_OK(resultBSON.getStatus());
 
@@ -180,116 +169,6 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtl) {
     auto chunkDoc0 = uassertStatusOK(getChunkDoc(operationContext(), chunkMin));
     ASSERT_EQ("shard1", chunkDoc0.getShard().toString());
     ASSERT_EQ(mver.getValue(), chunkDoc0.getVersion());
-    // The history should be updated.
-    ASSERT_EQ(2UL, chunkDoc0.getHistory().size());
-    ASSERT_EQ(validAfter, chunkDoc0.getHistory().front().getValidAfter());
-}
-
-TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtlTrimHistory) {
-
-    ShardType shard0;
-    shard0.setName("shard0");
-    shard0.setHost("shard0:12");
-
-    ShardType shard1;
-    shard1.setName("shard1");
-    shard1.setHost("shard1:12");
-
-    setupShards({shard0, shard1}).transitional_ignore();
-
-    int origMajorVersion = 15;
-    auto const origVersion = ChunkVersion(origMajorVersion, 4, OID::gen());
-
-    ChunkType chunk0;
-    chunk0.setNS(kNamespace);
-    chunk0.setVersion(origVersion);
-    chunk0.setShard(shard0.getName());
-    chunk0.setHistory({ChunkHistory(Timestamp(100, 0), ShardId("shardX"))});
-
-    // apportion
-    auto chunkMin = BSON("a" << 1);
-    chunk0.setMin(chunkMin);
-    auto chunkMax = BSON("a" << 10);
-    chunk0.setMax(chunkMax);
-
-    setupChunks({chunk0}).transitional_ignore();
-
-    // Make the time distance between the last history element large enough.
-    Timestamp validAfter{200, 0};
-
-    StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
-                                         ->commitChunkMigration(operationContext(),
-                                                                chunk0.getNS(),
-                                                                chunk0,
-                                                                boost::none,
-                                                                origVersion.epoch(),
-                                                                ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
-
-    ASSERT_OK(resultBSON.getStatus());
-
-    // Verify the version returned matches expected value.
-    BSONObj versions = resultBSON.getValue();
-    auto mver = ChunkVersion::parseFromBSONWithFieldForCommands(versions, "migratedChunkVersion");
-    ASSERT_OK(mver.getStatus());
-    ASSERT_EQ(ChunkVersion(origMajorVersion + 1, 0, origVersion.epoch()), mver.getValue());
-
-    auto cver = ChunkVersion::parseFromBSONWithFieldForCommands(versions, "controlChunkVersion");
-    ASSERT_NOT_OK(cver.getStatus());
-
-    // Verify the chunk ended up in the right shard, and version matches the value returned.
-    auto chunkDoc0 = uassertStatusOK(getChunkDoc(operationContext(), chunkMin));
-    ASSERT_EQ("shard1", chunkDoc0.getShard().toString());
-    ASSERT_EQ(mver.getValue(), chunkDoc0.getVersion());
-    // The history should be updated.
-    ASSERT_EQ(1UL, chunkDoc0.getHistory().size());
-    ASSERT_EQ(validAfter, chunkDoc0.getHistory().front().getValidAfter());
-}
-
-TEST_F(CommitChunkMigrate, RejectOutOfOrderHistory) {
-
-    ShardType shard0;
-    shard0.setName("shard0");
-    shard0.setHost("shard0:12");
-
-    ShardType shard1;
-    shard1.setName("shard1");
-    shard1.setHost("shard1:12");
-
-    setupShards({shard0, shard1}).transitional_ignore();
-
-    int origMajorVersion = 15;
-    auto const origVersion = ChunkVersion(origMajorVersion, 4, OID::gen());
-
-    ChunkType chunk0;
-    chunk0.setNS(kNamespace);
-    chunk0.setVersion(origVersion);
-    chunk0.setShard(shard0.getName());
-    chunk0.setHistory({ChunkHistory(Timestamp(100, 0), ShardId("shardX"))});
-
-    // apportion
-    auto chunkMin = BSON("a" << 1);
-    chunk0.setMin(chunkMin);
-    auto chunkMax = BSON("a" << 10);
-    chunk0.setMax(chunkMax);
-
-    setupChunks({chunk0}).transitional_ignore();
-
-    // Make the time before the last change to trigger the failure.
-    Timestamp validAfter{99, 0};
-
-    StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
-                                         ->commitChunkMigration(operationContext(),
-                                                                chunk0.getNS(),
-                                                                chunk0,
-                                                                boost::none,
-                                                                origVersion.epoch(),
-                                                                ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
-
-    ASSERT_EQ(ErrorCodes::IncompatibleShardingMetadata, resultBSON.getStatus());
 }
 
 TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch0) {
@@ -329,8 +208,6 @@ TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch0) {
 
     setupChunks({chunk0, chunk1}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
                                          ->commitChunkMigration(operationContext(),
                                                                 chunk0.getNS(),
@@ -338,8 +215,7 @@ TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch0) {
                                                                 chunk1,
                                                                 OID::gen(),
                                                                 ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
+                                                                ShardId(shard1.getName()));
 
     ASSERT_EQ(ErrorCodes::StaleEpoch, resultBSON.getStatus());
 }
@@ -383,8 +259,6 @@ TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch1) {
     // get version from the control chunk this time
     setupChunks({chunk1, chunk0}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
                                          ->commitChunkMigration(operationContext(),
                                                                 chunk0.getNS(),
@@ -392,8 +266,7 @@ TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch1) {
                                                                 chunk1,
                                                                 origVersion.epoch(),
                                                                 ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
+                                                                ShardId(shard1.getName()));
 
     ASSERT_EQ(ErrorCodes::StaleEpoch, resultBSON.getStatus());
 }
@@ -435,8 +308,6 @@ TEST_F(CommitChunkMigrate, RejectChunkMissing0) {
 
     setupChunks({chunk1}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
                                          ->commitChunkMigration(operationContext(),
                                                                 chunk0.getNS(),
@@ -444,8 +315,7 @@ TEST_F(CommitChunkMigrate, RejectChunkMissing0) {
                                                                 chunk1,
                                                                 origVersion.epoch(),
                                                                 ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
+                                                                ShardId(shard1.getName()));
 
     ASSERT_EQ(40165, resultBSON.getStatus().code());
 }
@@ -487,8 +357,6 @@ TEST_F(CommitChunkMigrate, RejectChunkMissing1) {
 
     setupChunks({chunk0}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     StatusWith<BSONObj> resultBSON = ShardingCatalogManager::get(operationContext())
                                          ->commitChunkMigration(operationContext(),
                                                                 chunk0.getNS(),
@@ -496,8 +364,7 @@ TEST_F(CommitChunkMigrate, RejectChunkMissing1) {
                                                                 chunk1,
                                                                 origVersion.epoch(),
                                                                 ShardId(shard0.getName()),
-                                                                ShardId(shard1.getName()),
-                                                                validAfter);
+                                                                ShardId(shard1.getName()));
 
     ASSERT_EQ(40165, resultBSON.getStatus().code());
 }
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp
index fee827a420f..3d115ec0a80 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_merge_chunks_test.cpp
@@ -67,15 +67,12 @@ TEST_F(MergeChunkTest, MergeExistingChunksCorrectlyShouldSucceed) {
 
     setupChunks({chunk, chunk2}).transitional_ignore();
 
-    Timestamp validAfter{100, 0};
-
     ASSERT_OK(ShardingCatalogManager::get(operationContext())
                   ->commitChunkMerge(operationContext(),
                                      NamespaceString("TestDB.TestColl"),
                                      origVersion.epoch(),
                                      chunkBoundaries,
-                                     "shard0000",
-                                     validAfter));
+                                     "shard0000"));
 
     auto findResponse = uassertStatusOK(
         getConfigShard()->exhaustiveFindOnConfig(operationContext(),
@@ -101,10 +98,6 @@ TEST_F(MergeChunkTest, MergeExistingChunksCorrectlyShouldSucceed) {
         ASSERT_EQ(origVersion.majorVersion(), mergedChunk.getVersion().majorVersion());
         ASSERT_EQ(origVersion.minorVersion() + 1, mergedChunk.getVersion().minorVersion());
     }
-
-    // Make sure history is there
-    ASSERT_EQ(1UL, mergedChunk.getHistory().size());
-    ASSERT_EQ(validAfter, mergedChunk.getHistory().front().getValidAfter());
 }
 
 TEST_F(MergeChunkTest, MergeSeveralChunksCorrectlyShouldSucceed) {
@@ -138,15 +131,12 @@ TEST_F(MergeChunkTest, MergeSeveralChunksCorrectlyShouldSucceed) {
 
     setupChunks({chunk, chunk2, chunk3}).transitional_ignore();
 
-    Timestamp validAfter{100, 0};
-
     ASSERT_OK(ShardingCatalogManager::get(operationContext())
                   ->commitChunkMerge(operationContext(),
                                      NamespaceString("TestDB.TestColl"),
                                      origVersion.epoch(),
                                      chunkBoundaries,
-                                     "shard0000",
-                                     validAfter));
+                                     "shard0000"));
 
     auto findResponse = uassertStatusOK(
         getConfigShard()->exhaustiveFindOnConfig(operationContext(),
@@ -172,10 +162,6 @@ TEST_F(MergeChunkTest, MergeSeveralChunksCorrectlyShouldSucceed) {
         ASSERT_EQ(origVersion.majorVersion(), mergedChunk.getVersion().majorVersion());
         ASSERT_EQ(origVersion.minorVersion() + 1, mergedChunk.getVersion().minorVersion());
     }
-
-    // Make sure history is there
-    ASSERT_EQ(1UL, mergedChunk.getHistory().size());
-    ASSERT_EQ(validAfter, mergedChunk.getHistory().front().getValidAfter());
 }
 
 TEST_F(MergeChunkTest, NewMergeShouldClaimHighestVersion) {
@@ -213,15 +199,12 @@ TEST_F(MergeChunkTest, NewMergeShouldClaimHighestVersion) {
 
     setupChunks({chunk, chunk2, otherChunk}).transitional_ignore();
 
-    Timestamp validAfter{100, 0};
-
     ASSERT_OK(ShardingCatalogManager::get(operationContext())
                   ->commitChunkMerge(operationContext(),
                                      NamespaceString("TestDB.TestColl"),
                                      collEpoch,
                                      chunkBoundaries,
-                                     "shard0000",
-                                     validAfter));
+                                     "shard0000"));
 
     auto findResponse = uassertStatusOK(
         getConfigShard()->exhaustiveFindOnConfig(operationContext(),
@@ -247,10 +230,6 @@ TEST_F(MergeChunkTest, NewMergeShouldClaimHighestVersion) {
         ASSERT_EQ(competingVersion.majorVersion(), mergedChunk.getVersion().majorVersion());
         ASSERT_EQ(competingVersion.minorVersion() + 1, mergedChunk.getVersion().minorVersion());
     }
-
-    // Make sure history is there
-    ASSERT_EQ(1UL, mergedChunk.getHistory().size());
-    ASSERT_EQ(validAfter, mergedChunk.getHistory().front().getValidAfter());
 }
 
 TEST_F(MergeChunkTest, MergeLeavesOtherChunksAlone) {
@@ -284,15 +263,12 @@ TEST_F(MergeChunkTest, MergeLeavesOtherChunksAlone) {
 
     setupChunks({chunk, chunk2, otherChunk}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     ASSERT_OK(ShardingCatalogManager::get(operationContext())
                   ->commitChunkMerge(operationContext(),
                                      NamespaceString("TestDB.TestColl"),
                                      origVersion.epoch(),
                                      chunkBoundaries,
-                                     "shard0000",
-                                     validAfter));
+                                     "shard0000"));
 
     auto findResponse = uassertStatusOK(
         getConfigShard()->exhaustiveFindOnConfig(operationContext(),
@@ -350,15 +326,12 @@ TEST_F(MergeChunkTest, NonExistingNamespace) {
 
     setupChunks({chunk, chunk2}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     auto mergeStatus = ShardingCatalogManager::get(operationContext())
                            ->commitChunkMerge(operationContext(),
                                               NamespaceString("TestDB.NonExistingColl"),
                                               origVersion.epoch(),
                                               chunkBoundaries,
-                                              "shard0000",
-                                              validAfter);
+                                              "shard0000");
     ASSERT_EQ(ErrorCodes::IllegalOperation, mergeStatus);
 }
 
@@ -387,15 +360,12 @@ TEST_F(MergeChunkTest, NonMatchingEpochsOfChunkAndRequestErrors) {
 
     setupChunks({chunk, chunk2}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     auto mergeStatus = ShardingCatalogManager::get(operationContext())
                            ->commitChunkMerge(operationContext(),
                                               NamespaceString("TestDB.TestColl"),
                                               OID::gen(),
                                               chunkBoundaries,
-                                              "shard0000",
-                                              validAfter);
+                                              "shard0000");
     ASSERT_EQ(ErrorCodes::StaleEpoch, mergeStatus);
 }
 
@@ -430,16 +400,13 @@ TEST_F(MergeChunkTest, MergeAlreadyHappenedFailsPrecondition) {
 
     setupChunks({mergedChunk}).transitional_ignore();
 
-    Timestamp validAfter{1};
-
     ASSERT_EQ(ErrorCodes::BadValue,
               ShardingCatalogManager::get(operationContext())
                   ->commitChunkMerge(operationContext(),
                                      NamespaceString("TestDB.TestColl"),
                                      origVersion.epoch(),
                                      chunkBoundaries,
-                                     "shard0000",
-                                     validAfter));
+                                     "shard0000"));
 
     // Verify that no change to config.chunks happened.
     auto findResponse = uassertStatusOK(
@@ -494,16 +461,13 @@ TEST_F(MergeChunkTest, ChunkBoundariesOutOfOrderFails) {
         setupChunks(originalChunks).transitional_ignore();
     }
 
-    Timestamp validAfter{1};
-
     ASSERT_EQ(ErrorCodes::InvalidOptions,
               ShardingCatalogManager::get(operationContext())
                   ->commitChunkMerge(operationContext(),
                                      NamespaceString("TestDB.TestColl"),
                                      epoch,
                                      chunkBoundaries,
-                                     "shard0000",
-                                     validAfter));
+                                     "shard0000"));
 }
 
 }  // namespace
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_split_chunk_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_split_chunk_test.cpp
index 932bc374745..31d3a794d41 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_split_chunk_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_split_chunk_test.cpp
@@ -53,8 +53,6 @@ TEST_F(SplitChunkTest, SplitExistingChunkCorrectlyShouldSucceed) {
     auto chunkMax = BSON("a" << 10);
     chunk.setMin(chunkMin);
     chunk.setMax(chunkMax);
-    chunk.setHistory({ChunkHistory(Timestamp(100, 0), ShardId("shardX")),
-                      ChunkHistory(Timestamp(90, 0), ShardId("shardY"))});
 
     auto chunkSplitPoint = BSON("a" << 5);
     std::vector<BSONObj> splitPoints{chunkSplitPoint};
@@ -80,9 +78,6 @@ TEST_F(SplitChunkTest, SplitExistingChunkCorrectlyShouldSucceed) {
     ASSERT_EQ(origVersion.majorVersion(), chunkDoc.getVersion().majorVersion());
     ASSERT_EQ(origVersion.minorVersion() + 1, chunkDoc.getVersion().minorVersion());
 
-    // Make sure the history is there
-    ASSERT_EQ(2UL, chunkDoc.getHistory().size());
-
     // Second chunkDoc should have range [chunkSplitPoint, chunkMax]
     auto otherChunkDocStatus = getChunkDoc(operationContext(), chunkSplitPoint);
     ASSERT_OK(otherChunkDocStatus.getStatus());
@@ -93,12 +88,6 @@ TEST_F(SplitChunkTest, SplitExistingChunkCorrectlyShouldSucceed) {
     // Check for increment on second chunkDoc's minor version
     ASSERT_EQ(origVersion.majorVersion(), otherChunkDoc.getVersion().majorVersion());
     ASSERT_EQ(origVersion.minorVersion() + 2, otherChunkDoc.getVersion().minorVersion());
-
-    // Make sure the history is there
-    ASSERT_EQ(2UL, otherChunkDoc.getHistory().size());
-
-    // Both chunks should have the same history
-    ASSERT(chunkDoc.getHistory() == otherChunkDoc.getHistory());
 }
 
 TEST_F(SplitChunkTest, MultipleSplitsOnExistingChunkShouldSucceed) {
@@ -113,8 +102,6 @@ TEST_F(SplitChunkTest, MultipleSplitsOnExistingChunkShouldSucceed) {
     auto chunkMax = BSON("a" << 10);
     chunk.setMin(chunkMin);
     chunk.setMax(chunkMax);
-    chunk.setHistory({ChunkHistory(Timestamp(100, 0), ShardId("shardX")),
-                      ChunkHistory(Timestamp(90, 0), ShardId("shardY"))});
 
     auto chunkSplitPoint = BSON("a" << 5);
     auto chunkSplitPoint2 = BSON("a" << 7);
@@ -141,9 +128,6 @@ TEST_F(SplitChunkTest, MultipleSplitsOnExistingChunkShouldSucceed) {
     ASSERT_EQ(origVersion.majorVersion(), chunkDoc.getVersion().majorVersion());
     ASSERT_EQ(origVersion.minorVersion() + 1, chunkDoc.getVersion().minorVersion());
 
-    // Make sure the history is there
-    ASSERT_EQ(2UL, chunkDoc.getHistory().size());
-
     // Second chunkDoc should have range [chunkSplitPoint, chunkSplitPoint2]
     auto midChunkDocStatus = getChunkDoc(operationContext(), chunkSplitPoint);
     ASSERT_OK(midChunkDocStatus.getStatus());
@@ -155,9 +139,6 @@ TEST_F(SplitChunkTest, MultipleSplitsOnExistingChunkShouldSucceed) {
     ASSERT_EQ(origVersion.majorVersion(), midChunkDoc.getVersion().majorVersion());
     ASSERT_EQ(origVersion.minorVersion() + 2, midChunkDoc.getVersion().minorVersion());
 
-    // Make sure the history is there
-    ASSERT_EQ(2UL, midChunkDoc.getHistory().size());
-
     // Third chunkDoc should have range [chunkSplitPoint2, chunkMax]
     auto lastChunkDocStatus = getChunkDoc(operationContext(), chunkSplitPoint2);
     ASSERT_OK(lastChunkDocStatus.getStatus());
@@ -168,13 +149,6 @@ TEST_F(SplitChunkTest, MultipleSplitsOnExistingChunkShouldSucceed) {
     // Check for increment on third chunkDoc's minor version
     ASSERT_EQ(origVersion.majorVersion(), lastChunkDoc.getVersion().majorVersion());
     ASSERT_EQ(origVersion.minorVersion() + 3, lastChunkDoc.getVersion().minorVersion());
-
-    // Make sure the history is there
-    ASSERT_EQ(2UL, lastChunkDoc.getHistory().size());
-
-    // Both chunks should have the same history
-    ASSERT(chunkDoc.getHistory() == midChunkDoc.getHistory());
-    ASSERT(midChunkDoc.getHistory() == lastChunkDoc.getHistory());
 }
 
 TEST_F(SplitChunkTest, NewSplitShouldClaimHighestVersion) {
diff --git a/src/mongo/db/s/merge_chunks_command.cpp b/src/mongo/db/s/merge_chunks_command.cpp
index 7d523de8854..0458815e990 100644
--- a/src/mongo/db/s/merge_chunks_command.cpp
+++ b/src/mongo/db/s/merge_chunks_command.cpp
@@ -36,7 +36,6 @@
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/field_parser.h"
-#include "mongo/db/logical_clock.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/s/collection_sharding_state.h"
 #include "mongo/db/s/shard_filtering_metadata_refresh.h"
@@ -241,11 +240,8 @@ Status mergeChunks(OperationContext* opCtx,
     //
     // Run _configsvrCommitChunkMerge.
     //
-    MergeChunkRequest request{nss,
-                              shardingState->getShardName(),
-                              shardVersion.epoch(),
-                              chunkBoundaries,
-                              LogicalClock::get(opCtx)->getClusterTime().asTimestamp()};
+    MergeChunkRequest request{
+        nss, shardingState->getShardName(), shardVersion.epoch(), chunkBoundaries};
 
     auto configCmdObj =
         request.toConfigCommandBSON(ShardingCatalogClient::kMajorityWriteConcern.toBSON());
diff --git a/src/mongo/db/s/migration_source_manager.cpp b/src/mongo/db/s/migration_source_manager.cpp
index bb0dc85c807..8f113193f1e 100644
--- a/src/mongo/db/s/migration_source_manager.cpp
+++ b/src/mongo/db/s/migration_source_manager.cpp
@@ -35,7 +35,6 @@
 #include "mongo/bson/bsonobjbuilder.h"
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
-#include "mongo/db/logical_clock.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/s/migration_chunk_cloner_source_legacy.h"
@@ -409,15 +408,13 @@ Status MigrationSourceManager::commitChunkMetadataOnConfig(OperationContext* opC
         migratedChunkType.setMin(_args.getMinKey());
         migratedChunkType.setMax(_args.getMaxKey());
 
-        CommitChunkMigrationRequest::appendAsCommand(
-            &builder,
-            getNss(),
-            _args.getFromShardId(),
-            _args.getToShardId(),
-            migratedChunkType,
-            controlChunkType,
-            metadata->getCollVersion(),
-            LogicalClock::get(opCtx)->getClusterTime().asTimestamp());
+        CommitChunkMigrationRequest::appendAsCommand(&builder,
+                                                     getNss(),
+                                                     _args.getFromShardId(),
+                                                     _args.getToShardId(),
+                                                     migratedChunkType,
+                                                     controlChunkType,
+                                                     metadata->getCollVersion());
 
         builder.append(kWriteConcernField, kMajorityWriteConcern.toBSON());
     }
diff --git a/src/mongo/s/SConscript b/src/mongo/s/SConscript
index 59aeadf2017..6b668e0c4ca 100644
--- a/src/mongo/s/SConscript
+++ b/src/mongo/s/SConscript
@@ -130,7 +130,6 @@ env.Library(
         'request_types/update_zone_key_range_request_type.cpp',
         'shard_id.cpp',
         'versioning.cpp',
-        env.Idlc('catalog/type_chunk_base.idl')[0],
         env.Idlc('request_types/create_collection.idl')[0],
         env.Idlc('request_types/create_database.idl')[0],
         env.Idlc('request_types/flush_routing_table_cache_updates.idl')[0],
diff --git a/src/mongo/s/catalog/type_chunk.cpp b/src/mongo/s/catalog/type_chunk.cpp
index 5aa3132a78e..58a181240a9 100644
--- a/src/mongo/s/catalog/type_chunk.cpp
+++ b/src/mongo/s/catalog/type_chunk.cpp
@@ -54,7 +54,6 @@ const BSONField<std::string> ChunkType::shard("shard");
 const BSONField<bool> ChunkType::jumbo("jumbo");
 const BSONField<Date_t> ChunkType::lastmod("lastmod");
 const BSONField<OID> ChunkType::epoch("lastmodEpoch");
-const BSONField<BSONObj> ChunkType::history("history");
 
 namespace {
 
@@ -158,23 +157,6 @@ ChunkRange ChunkRange::unionWith(ChunkRange const& other) const {
                       le(_maxKey, other._maxKey) ? other._maxKey : _maxKey);
 }
 
-StatusWith<std::vector<ChunkHistory>> ChunkHistory::fromBSON(const BSONArray& source) {
-    std::vector<ChunkHistory> values;
-
-    for (const auto& arrayElement : source) {
-        if (arrayElement.type() == Object) {
-            IDLParserErrorContext tempContext("chunk history array");
-            values.emplace_back(ChunkHistoryBase::parse(tempContext, arrayElement.Obj()));
-        } else {
-            return {ErrorCodes::BadValue,
-                    str::stream() << "array element does not have the object type: "
-                                  << arrayElement.type()};
-        }
-    }
-
-    return values;
-}
-
 // ChunkType
 
 ChunkType::ChunkType() = default;
@@ -235,22 +217,6 @@ StatusWith<ChunkType> ChunkType::fromConfigBSON(const BSONObj& source) {
         chunk._version = std::move(versionStatus.getValue());
     }
 
-    {
-        BSONElement historyObj;
-        Status status = bsonExtractTypedField(source, history.name(), Array, &historyObj);
-        if (status.isOK()) {
-            auto history = std::move(ChunkHistory::fromBSON(BSONArray(historyObj.Obj())));
-            if (!history.isOK())
-                return history.getStatus();
-
-            chunk._history = std::move(history.getValue());
-        } else if (status == ErrorCodes::NoSuchKey) {
-            // History is missing, so it will be presumed empty
-        } else {
-            return status;
-        }
-    }
-
     return chunk;
 }
 
@@ -270,7 +236,7 @@ BSONObj ChunkType::toConfigBSON() const {
         _version->appendForChunk(&builder);
     if (_jumbo)
         builder.append(jumbo.name(), getJumbo());
-    addHistoryToBSON(builder);
+
     return builder.obj();
 }
 
@@ -317,22 +283,6 @@ StatusWith<ChunkType> ChunkType::fromShardBSON(const BSONObj& source, const OID&
         chunk._version = std::move(statusWithChunkVersion.getValue());
     }
 
-    {
-        BSONElement historyObj;
-        Status status = bsonExtractTypedField(source, history.name(), Array, &historyObj);
-        if (status.isOK()) {
-            auto history = std::move(ChunkHistory::fromBSON(BSONArray(historyObj.Obj())));
-            if (!history.isOK())
-                return history.getStatus();
-
-            chunk._history = std::move(history.getValue());
-        } else if (status == ErrorCodes::NoSuchKey) {
-            // History is missing, so it will be presumed empty
-        } else {
-            return status;
-        }
-    }
-
     return chunk;
 }
 
@@ -346,7 +296,6 @@ BSONObj ChunkType::toShardBSON() const {
     builder.append(max.name(), getMax());
     builder.append(shard.name(), getShard().toString());
     builder.appendTimestamp(lastmod.name(), _version->toLong());
-    addHistoryToBSON(builder);
     return builder.obj();
 }
 
@@ -385,16 +334,6 @@ void ChunkType::setJumbo(bool jumbo) {
     _jumbo = jumbo;
 }
 
-void ChunkType::addHistoryToBSON(BSONObjBuilder& builder) const {
-    if (_history.size()) {
-        BSONArrayBuilder arrayBuilder(builder.subarrayStart(history.name()));
-        for (const auto& item : _history) {
-            BSONObjBuilder subObjBuilder(arrayBuilder.subobjStart());
-            item.serialize(&subObjBuilder);
-        }
-    }
-}
-
 std::string ChunkType::genID(const NamespaceString& nss, const BSONObj& o) {
     StringBuilder buf;
     buf << nss.ns() << "-";
diff --git a/src/mongo/s/catalog/type_chunk.h b/src/mongo/s/catalog/type_chunk.h
index 139e2d1dfa9..b4998af3c9a 100644
--- a/src/mongo/s/catalog/type_chunk.h
+++ b/src/mongo/s/catalog/type_chunk.h
@@ -33,7 +33,6 @@
 
 #include "mongo/bson/bsonobj.h"
 #include "mongo/db/namespace_string.h"
-#include "mongo/s/catalog/type_chunk_base_gen.h"
 #include "mongo/s/chunk_version.h"
 #include "mongo/s/shard_id.h"
 
@@ -105,22 +104,6 @@ private:
     BSONObj _maxKey;
 };
 
-class ChunkHistory : public ChunkHistoryBase {
-public:
-    ChunkHistory() : ChunkHistoryBase() {}
-    ChunkHistory(mongo::Timestamp ts, mongo::ShardId shard) : ChunkHistoryBase() {
-        setValidAfter(std::move(ts));
-        setShard(std::move(shard));
-    }
-    ChunkHistory(const ChunkHistoryBase& b) : ChunkHistoryBase(b) {}
-
-    static StatusWith<std::vector<ChunkHistory>> fromBSON(const BSONArray& source);
-
-    bool operator==(const ChunkHistory& other) const {
-        return getValidAfter() == other.getValidAfter() && getShard() == other.getShard();
-    }
-};
-
 /**
  * This class represents the layouts and contents of documents contained in the config server's
  * config.chunks and shard server's config.chunks.uuid collections. All manipulation of documents
@@ -179,7 +162,6 @@ public:
     static const BSONField<bool> jumbo;
     static const BSONField<Date_t> lastmod;
     static const BSONField<OID> epoch;
-    static const BSONField<BSONObj> history;
 
     ChunkType();
     ChunkType(NamespaceString nss, ChunkRange range, ChunkVersion version, ShardId shardId);
@@ -254,15 +236,6 @@ public:
     }
     void setJumbo(bool jumbo);
 
-    void setHistory(std::vector<ChunkHistory>&& history) {
-        _history = std::move(history);
-    }
-    const std::vector<ChunkHistory>& getHistory() const {
-        return _history;
-    }
-
-    void addHistoryToBSON(BSONObjBuilder& builder) const;
-
     /**
      * Generates chunk id based on the namespace name and the lower bound of the chunk.
      */
@@ -294,8 +267,6 @@ private:
     boost::optional<ShardId> _shard;
     // (O)(C)     too big to move?
     boost::optional<bool> _jumbo;
-    // history of the chunk
-    std::vector<ChunkHistory> _history;
 };
 
 }  // namespace mongo
diff --git a/src/mongo/s/catalog/type_chunk_base.idl b/src/mongo/s/catalog/type_chunk_base.idl
deleted file mode 100644
index c1741a14f3f..00000000000
--- a/src/mongo/s/catalog/type_chunk_base.idl
+++ /dev/null
@@ -1,44 +0,0 @@
-# Copyright (C) 2018 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/>.
-#
-
-# ChunkTypeBase type
-
-global:
-    cpp_namespace: "mongo"
-    cpp_includes:
-        - "mongo/s/shard_id.h"
-
-imports:
-    - "mongo/idl/basic_types.idl"
-
-types:
-    shardid:
-        bson_serialization_type: string
-        description: "A BSON UTF-8 string"
-        cpp_type: "ShardId"
-        deserializer: "mongo::BSONElement::str"
-        serializer: "mongo::ShardId::toString"
-
-structs:
-    ChunkHistoryBase:
-        description: "An element of a chunk history array. The array holds the history ordered from
-                      the most recent (the index 0) to the oldest supported."
-        fields:
-            validAfter:
-                type: timestamp
-                description: The time after which this chunk is at this shard.
-            shard:
-                type: shardid
-                description: Shard this chunk lives in, starting at the "validAfter" time.
diff --git a/src/mongo/s/chunk.cpp b/src/mongo/s/chunk.cpp
index 21067acd7e0..527440594eb 100644
--- a/src/mongo/s/chunk.cpp
+++ b/src/mongo/s/chunk.cpp
@@ -61,7 +61,6 @@ Chunk::Chunk(const ChunkType& from)
     : _range(from.getMin(), from.getMax()),
       _shardId(from.getShard()),
       _lastmod(from.getVersion()),
-      _history(from.getHistory()),
       _jumbo(from.getJumbo()),
       _dataWritten(mkDataWritten()) {
     invariantOK(from.validate());
diff --git a/src/mongo/s/chunk.h b/src/mongo/s/chunk.h
index 31205aefc25..540238463b5 100644
--- a/src/mongo/s/chunk.h
+++ b/src/mongo/s/chunk.h
@@ -98,8 +98,6 @@ private:
 
     const ChunkVersion _lastmod;
 
-    const std::vector<ChunkHistory> _history;
-
     // Indicates whether this chunk should be treated as jumbo and not attempted to be moved or
     // split
     mutable bool _jumbo;
diff --git a/src/mongo/s/request_types/commit_chunk_migration_request_test.cpp b/src/mongo/s/request_types/commit_chunk_migration_request_test.cpp
index afc887745f0..9c5f513ac60 100644
--- a/src/mongo/s/request_types/commit_chunk_migration_request_test.cpp
+++ b/src/mongo/s/request_types/commit_chunk_migration_request_test.cpp
@@ -65,16 +65,13 @@ TEST(CommitChunkMigrationRequest, WithControlChunk) {
     controlChunk.setMax(kKey3);
     boost::optional<ChunkType> controlChunkOpt = controlChunk;
 
-    Timestamp validAfter{1};
-
     CommitChunkMigrationRequest::appendAsCommand(&builder,
                                                  kNamespaceString,
                                                  kShardId0,
                                                  kShardId1,
                                                  migratedChunk,
                                                  controlChunkOpt,
-                                                 fromShardCollectionVersion,
-                                                 validAfter);
+                                                 fromShardCollectionVersion);
 
     BSONObj cmdObj = builder.obj();
 
@@ -101,16 +98,13 @@ TEST(CommitChunkMigrationRequest, WithoutControlChunk) {
 
     ChunkVersion fromShardCollectionVersion(1, 2, OID::gen());
 
-    Timestamp validAfter{1};
-
     CommitChunkMigrationRequest::appendAsCommand(&builder,
                                                  kNamespaceString,
                                                  kShardId0,
                                                  kShardId1,
                                                  migratedChunk,
                                                  boost::none,
-                                                 fromShardCollectionVersion,
-                                                 validAfter);
+                                                 fromShardCollectionVersion);
 
     BSONObj cmdObj = builder.obj();
 
diff --git a/src/mongo/s/request_types/commit_chunk_migration_request_type.cpp b/src/mongo/s/request_types/commit_chunk_migration_request_type.cpp
index 463ee0d4a92..1f1125529cb 100644
--- a/src/mongo/s/request_types/commit_chunk_migration_request_type.cpp
+++ b/src/mongo/s/request_types/commit_chunk_migration_request_type.cpp
@@ -41,7 +41,6 @@ const char kToShard[] = "toShard";
 const char kMigratedChunk[] = "migratedChunk";
 const char kControlChunk[] = "controlChunk";
 const char kFromShardCollectionVersion[] = "fromShardCollectionVersion";
-const char kValidAfter[] = "validAfter";
 
 /**
  * Attempts to parse a (range-only!) ChunkType from "field" in "source".
@@ -133,20 +132,6 @@ StatusWith<CommitChunkMigrationRequest> CommitChunkMigrationRequest::createFromC
         request._collectionEpoch = statusWithChunkVersion.getValue().epoch();
     }
 
-    {
-        Timestamp validAfter;
-        auto status = bsonExtractTimestampField(obj, kValidAfter, &validAfter);
-        if (!status.isOK() && status != ErrorCodes::NoSuchKey) {
-            return status;
-        }
-
-        if (status.isOK()) {
-            request._validAfter = validAfter;
-        } else {
-            request._validAfter = boost::none;
-        }
-    }
-
     return request;
 }
 
@@ -156,8 +141,7 @@ void CommitChunkMigrationRequest::appendAsCommand(BSONObjBuilder* builder,
                                                   const ShardId& toShard,
                                                   const ChunkType& migratedChunk,
                                                   const boost::optional<ChunkType>& controlChunk,
-                                                  const ChunkVersion& fromShardCollectionVersion,
-                                                  const Timestamp& validAfter) {
+                                                  const ChunkVersion& fromShardCollectionVersion) {
     invariant(builder->asTempObj().isEmpty());
     invariant(nss.isValid());
 
@@ -170,7 +154,6 @@ void CommitChunkMigrationRequest::appendAsCommand(BSONObjBuilder* builder,
     if (controlChunk) {
         builder->append(kControlChunk, controlChunk->toConfigBSON());
     }
-    builder->append(kValidAfter, validAfter);
 }
 
 }  // namespace mongo
diff --git a/src/mongo/s/request_types/commit_chunk_migration_request_type.h b/src/mongo/s/request_types/commit_chunk_migration_request_type.h
index f403572e46e..919db71870d 100644
--- a/src/mongo/s/request_types/commit_chunk_migration_request_type.h
+++ b/src/mongo/s/request_types/commit_chunk_migration_request_type.h
@@ -60,8 +60,7 @@ struct CommitChunkMigrationRequest {
                                 const ShardId& toShard,
                                 const ChunkType& migratedChunkType,
                                 const boost::optional<ChunkType>& controlChunkType,
-                                const ChunkVersion& fromShardChunkVersion,
-                                const Timestamp& validAfter);
+                                const ChunkVersion& fromShardChunkVersion);
 
     const NamespaceString& getNss() const {
         return _nss;
@@ -81,9 +80,6 @@ struct CommitChunkMigrationRequest {
     const OID& getCollectionEpoch() {
         return _collectionEpoch;
     }
-    const boost::optional<Timestamp>& getValidAfter() {
-        return _validAfter;
-    }
 
     // The collection for which this request applies.
     NamespaceString _nss;
@@ -101,9 +97,6 @@ struct CommitChunkMigrationRequest {
     boost::optional<ChunkType> _controlChunk;
 
     OID _collectionEpoch;
-
-    // The time of the move
-    boost::optional<Timestamp> _validAfter;
 };
 
 }  // namespace mongo
diff --git a/src/mongo/s/request_types/merge_chunk_request_test.cpp b/src/mongo/s/request_types/merge_chunk_request_test.cpp
index ce8b7366a9e..de9ecd7990c 100644
--- a/src/mongo/s/request_types/merge_chunk_request_test.cpp
+++ b/src/mongo/s/request_types/merge_chunk_request_test.cpp
@@ -64,9 +64,7 @@ TEST(MergeChunkRequest, ConfigCommandtoBSON) {
              << "chunkBoundaries"
              << BSON_ARRAY(BSON("a" << 1) << BSON("a" << 5) << BSON("a" << 10))
              << "shard"
-             << "shard0000"
-             << "validAfter"
-             << Timestamp{100});
+             << "shard0000");
     BSONObj writeConcernObj = BSON("writeConcern" << BSON("w"
                                                           << "majority"));
 
diff --git a/src/mongo/s/request_types/merge_chunk_request_type.cpp b/src/mongo/s/request_types/merge_chunk_request_type.cpp
index abace857a99..64200b85460 100644
--- a/src/mongo/s/request_types/merge_chunk_request_type.cpp
+++ b/src/mongo/s/request_types/merge_chunk_request_type.cpp
@@ -40,19 +40,17 @@ const char kConfigsvrMergeChunk[] = "_configsvrCommitChunkMerge";
 const char kCollEpoch[] = "collEpoch";
 const char kChunkBoundaries[] = "chunkBoundaries";
 const char kShardName[] = "shard";
-const char kValidAfter[] = "validAfter";
+
 }  // namespace
 
 MergeChunkRequest::MergeChunkRequest(NamespaceString nss,
                                      std::string shardName,
                                      OID epoch,
-                                     std::vector<BSONObj> chunkBoundaries,
-                                     boost::optional<Timestamp> validAfter)
+                                     std::vector<BSONObj> chunkBoundaries)
     : _nss(std::move(nss)),
       _epoch(std::move(epoch)),
       _chunkBoundaries(std::move(chunkBoundaries)),
-      _shardName(std::move(shardName)),
-      _validAfter(validAfter) {}
+      _shardName(std::move(shardName)) {}
 
 StatusWith<MergeChunkRequest> MergeChunkRequest::parseFromConfigCommand(const BSONObj& cmdObj) {
     std::string ns;
@@ -105,24 +103,8 @@ StatusWith<MergeChunkRequest> MergeChunkRequest::parseFromConfigCommand(const BS
         }
     }
 
-    boost::optional<Timestamp> validAfter = boost::none;
-    {
-        Timestamp ts{0};
-        auto status = bsonExtractTimestampField(cmdObj, kValidAfter, &ts);
-        if (!status.isOK() && status != ErrorCodes::NoSuchKey) {
-            return status;
-        }
-
-        if (status.isOK()) {
-            validAfter = ts;
-        }
-    }
-
-    return MergeChunkRequest(std::move(nss),
-                             std::move(shardName),
-                             std::move(epoch),
-                             std::move(chunkBoundaries),
-                             validAfter);
+    return MergeChunkRequest(
+        std::move(nss), std::move(shardName), std::move(epoch), std::move(chunkBoundaries));
 }
 
 BSONObj MergeChunkRequest::toConfigCommandBSON(const BSONObj& writeConcern) {
@@ -145,8 +127,6 @@ void MergeChunkRequest::appendAsConfigCommand(BSONObjBuilder* cmdBuilder) {
         }
     }
     cmdBuilder->append(kShardName, _shardName);
-    invariant(_validAfter.is_initialized());
-    cmdBuilder->append(kValidAfter, _validAfter.get());
 }
 
 }  // namespace mongo
diff --git a/src/mongo/s/request_types/merge_chunk_request_type.h b/src/mongo/s/request_types/merge_chunk_request_type.h
index 2722c53b057..2ead5f3a9b1 100644
--- a/src/mongo/s/request_types/merge_chunk_request_type.h
+++ b/src/mongo/s/request_types/merge_chunk_request_type.h
@@ -46,8 +46,7 @@ public:
     MergeChunkRequest(NamespaceString nss,
                       std::string shardName,
                       OID epoch,
-                      std::vector<BSONObj> chunkBoundaries,
-                      boost::optional<Timestamp> validAfter);
+                      std::vector<BSONObj> chunkBoundaries);
 
     /**
      * Parses the provided BSON content as the internal _configsvrCommitChunkMerge command, and if
@@ -95,10 +94,6 @@ public:
         return _shardName;
     }
 
-    const boost::optional<Timestamp>& getValidAfter() const {
-        return _validAfter;
-    }
-
 private:
     NamespaceString _nss;
     OID _epoch;
@@ -107,8 +102,6 @@ private:
     std::vector<BSONObj> _chunkBoundaries;
 
     std::string _shardName;
-
-    boost::optional<Timestamp> _validAfter;
 };
 
 }  // namespace mongo