SERVER-39085 IndexBuildsManager supports relaxing index constraints during index builds

5 files changed, 54 insertions, 28 deletions

diff --git a/src/mongo/db/catalog/index_builds_manager.cpp b/src/mongo/db/catalog/index_builds_manager.cpp
index a9e1bbee205..e016e0538d9 100644
--- a/src/mongo/db/catalog/index_builds_manager.cpp
+++ b/src/mongo/db/catalog/index_builds_manager.cpp
@@ -69,6 +69,8 @@ std::string toSummary(const std::map<UUID, std::shared_ptr<MultiIndexBlock>>& bu
 
 }  // namespace
 
+IndexBuildsManager::SetupOptions::SetupOptions() = default;
+
 IndexBuildsManager::~IndexBuildsManager() {
     invariant(_builders.empty(),
               str::stream() << "Index builds still active: " << toSummary(_builders));
@@ -79,7 +81,7 @@ Status IndexBuildsManager::setUpIndexBuild(OperationContext* opCtx,
                                            const std::vector<BSONObj>& specs,
                                            const UUID& buildUUID,
                                            OnInitFn onInit,
-                                           bool forRecovery) {
+                                           SetupOptions options) {
     _registerIndexBuild(buildUUID);
 
     const auto& nss = collection->ns();
@@ -90,6 +92,13 @@ Status IndexBuildsManager::setUpIndexBuild(OperationContext* opCtx,
 
     auto builder = _getBuilder(buildUUID);
 
+    // Ignore uniqueness constraint violations when relaxed (on secondaries). Secondaries can
+    // complete index builds in the middle of batches, which creates the potential for finding
+    // duplicate key violations where there otherwise would be none at consistent states.
+    if (options.indexConstraints == IndexConstraints::kRelax) {
+        builder->ignoreUniqueConstraint();
+    }
+
     auto initResult = writeConflictRetry(opCtx,
                                          "IndexBuildsManager::setUpIndexBuild",
                                          nss.ns(),
@@ -101,7 +110,7 @@ Status IndexBuildsManager::setUpIndexBuild(OperationContext* opCtx,
         return initResult.getStatus();
     }
 
-    if (forRecovery) {
+    if (options.forRecovery) {
         log() << "Index build initialized: " << buildUUID << ": " << nss
               << ": indexes: " << initResult.getValue().size();
     } else {
diff --git a/src/mongo/db/catalog/index_builds_manager.h b/src/mongo/db/catalog/index_builds_manager.h
index 255fdeba875..e2f23ad4bb6 100644
--- a/src/mongo/db/catalog/index_builds_manager.h
+++ b/src/mongo/db/catalog/index_builds_manager.h
@@ -56,6 +56,20 @@ class IndexBuildsManager {
     MONGO_DISALLOW_COPYING(IndexBuildsManager);
 
 public:
+    /**
+     * Indicates whether or not to ignore indexing constraints.
+     */
+    enum class IndexConstraints { kEnforce, kRelax };
+
+    /**
+     * Additional options for setUpIndexBuild. The default values are sufficient in most cases.
+     */
+    struct SetupOptions {
+        SetupOptions();
+        IndexConstraints indexConstraints = IndexConstraints::kEnforce;
+        bool forRecovery = false;
+    };
+
     IndexBuildsManager() = default;
     ~IndexBuildsManager();
 
@@ -68,7 +82,7 @@ public:
                            const std::vector<BSONObj>& specs,
                            const UUID& buildUUID,
                            OnInitFn onInit,
-                           bool forRecovery);
+                           SetupOptions options = {});
 
     /**
      * Recovers the index build from its persisted state and sets it up to run again.
diff --git a/src/mongo/db/catalog/index_builds_manager_test.cpp b/src/mongo/db/catalog/index_builds_manager_test.cpp
index c9820fafd15..3ecb5dca2a1 100644
--- a/src/mongo/db/catalog/index_builds_manager_test.cpp
+++ b/src/mongo/db/catalog/index_builds_manager_test.cpp
@@ -90,8 +90,7 @@ TEST_F(IndexBuildsManagerTest, IndexBuildsManagerSetUpAndTearDown) {
                                                   autoColl.getCollection(),
                                                   specs,
                                                   _buildUUID,
-                                                  MultiIndexBlock::kNoopOnInitFn,
-                                                  /*forRecovery=*/false));
+                                                  MultiIndexBlock::kNoopOnInitFn));
 
     _indexBuildsManager.tearDownIndexBuild(
         operationContext(), autoColl.getCollection(), _buildUUID);
diff --git a/src/mongo/db/index_builder.h b/src/mongo/db/index_builder.h
index 8bb455aef0c..e90815ec510 100644
--- a/src/mongo/db/index_builder.h
+++ b/src/mongo/db/index_builder.h
@@ -70,7 +70,7 @@ class OperationContext;
 class IndexBuilder : public BackgroundJob {
 public:
     /**
-     * Indicates whether or not to ignore indexing errors.
+     * Indicates whether or not to ignore indexing constraints.
      */
     enum class IndexConstraints { kEnforce, kRelax };
 
diff --git a/src/mongo/db/index_builds_coordinator.cpp b/src/mongo/db/index_builds_coordinator.cpp
index 7c6e82917e2..0923210b8ab 100644
--- a/src/mongo/db/index_builds_coordinator.cpp
+++ b/src/mongo/db/index_builds_coordinator.cpp
@@ -244,12 +244,10 @@ StatusWith<std::pair<long long, long long>> IndexBuildsCoordinator::startIndexRe
         indexCatalogStats.numIndexesBefore =
             _getNumIndexesTotal(opCtx, collection.get()) + indexNames.size();
 
-        status = _indexBuildsManager.setUpIndexBuild(opCtx,
-                                                     collection.get(),
-                                                     specs,
-                                                     buildUUID,
-                                                     MultiIndexBlock::kNoopOnInitFn,
-                                                     /*forRecovery=*/true);
+        IndexBuildsManager::SetupOptions options;
+        options.forRecovery = true;
+        status = _indexBuildsManager.setUpIndexBuild(
+            opCtx, collection.get(), specs, buildUUID, MultiIndexBlock::kNoopOnInitFn, options);
         if (!status.isOK()) {
             // An index build failure during recovery is fatal.
             logFailure(status, nss, replIndexBuildState);
@@ -611,25 +609,31 @@ IndexBuildsCoordinator::_registerAndSetUpIndexBuild(
         onInitFn = MultiIndexBlock::makeTimestampedIndexOnInitFn(opCtx, collection);
     }
 
-    status = _indexBuildsManager.setUpIndexBuild(opCtx,
-                                                 collection,
-                                                 filteredSpecs,
-                                                 replIndexBuildState->buildUUID,
-                                                 onInitFn,
-                                                 /*forRecovery=*/false);
-    if (!status.isOK()) {
-        // Unregister the index build before setting the promise, so callers do not see the
-        // build
-        // again.
-        _unregisterIndexBuild(lk, replIndexBuildState);
+    IndexBuildsManager::SetupOptions options;
+    options.indexConstraints =
+        repl::ReplicationCoordinator::get(opCtx)->shouldRelaxIndexConstraints(opCtx, nss)
+        ? IndexBuildsManager::IndexConstraints::kRelax
+        : IndexBuildsManager::IndexConstraints::kEnforce;
+    status = _indexBuildsManager.setUpIndexBuild(
+        opCtx, collection, filteredSpecs, replIndexBuildState->buildUUID, onInitFn, options);
+
+    // Indexes are present in the catalog in an unfinished state. Return an uninitialized
+    // Future so that the caller will continue building the indexes by calling _runIndexBuild().
+    // The completion of the index build will be communicated via a Future obtained from
+    // 'replIndexBuildState->sharedPromise'.
+    if (status.isOK()) {
+        return boost::none;
+    }
 
-        // Set the promise in case another thread already joined the index build.
-        replIndexBuildState->sharedPromise.setError(status);
+    _indexBuildsManager.tearDownIndexBuild(opCtx, collection, replIndexBuildState->buildUUID);
 
-        return status;
-    }
+    // Unregister the index build before setting the promise, so callers do not see the build again.
+    _unregisterIndexBuild(lk, replIndexBuildState);
+
+    // Set the promise in case another thread already joined the index build.
+    replIndexBuildState->sharedPromise.setError(status);
 
-    return boost::none;
+    return status;
 }
 
 void IndexBuildsCoordinator::_runIndexBuild(OperationContext* opCtx,