SERVER-30351 Add a traverseRecordStore() function in the RecordStoreValidateAdaptor

3 files changed, 77 insertions, 7 deletions

diff --git a/src/mongo/db/catalog/collection_impl.cpp b/src/mongo/db/catalog/collection_impl.cpp
index c229698b205..b4780bd66a7 100644
--- a/src/mongo/db/catalog/collection_impl.cpp
+++ b/src/mongo/db/catalog/collection_impl.cpp
@@ -1007,16 +1007,21 @@ using ValidateResultsMap = std::map<std::string, ValidateResults>;
 void _validateRecordStore(OperationContext* opCtx,
                           RecordStore* recordStore,
                           ValidateCmdLevel level,
+                          bool background,
                           RecordStoreValidateAdaptor* indexValidator,
                           ValidateResults* results,
                           BSONObjBuilder* output) {
 
-    // Validate RecordStore and, if `level == kValidateFull`, cross validate indexes and
-    // RecordStore.
-    auto status = recordStore->validate(opCtx, level, indexValidator, results, output);
-    // RecordStore::validate always returns Status::OK(). Errors are reported through
-    // `results`.
-    dassert(status.isOK());
+    // Validate RecordStore and, if `level == kValidateFull`, use the RecordStore's validate
+    // function.
+    if (background) {
+        indexValidator->traverseRecordStore(recordStore, level, results, output);
+    } else {
+        auto status = recordStore->validate(opCtx, level, indexValidator, results, output);
+        // RecordStore::validate always returns Status::OK(). Errors are reported through
+        // `results`.
+        dassert(status.isOK());
+    }
 }
 
 void _validateIndexes(OperationContext* opCtx,
@@ -1165,7 +1170,8 @@ Status CollectionImpl::validate(OperationContext* opCtx,
 
         // Validate the record store
         log(LogComponent::kIndex) << "validating collection " << ns().toString() << endl;
-        _validateRecordStore(opCtx, _recordStore, level, &indexValidator, results, output);
+        _validateRecordStore(
+            opCtx, _recordStore, level, /*somgarg*/ false, &indexValidator, results, output);
 
         // Validate indexes and check for mismatches.
         if (results->valid) {
diff --git a/src/mongo/db/catalog/private/record_store_validate_adaptor.cpp b/src/mongo/db/catalog/private/record_store_validate_adaptor.cpp
index a7f70e96b9f..8b978820b9b 100644
--- a/src/mongo/db/catalog/private/record_store_validate_adaptor.cpp
+++ b/src/mongo/db/catalog/private/record_store_validate_adaptor.cpp
@@ -42,6 +42,7 @@
 #include "mongo/db/storage/key_string.h"
 #include "mongo/db/storage/record_store.h"
 #include "mongo/rpc/object_check.h"
+#include "mongo/util/log.h"
 
 namespace mongo {
 
@@ -186,6 +187,60 @@ void RecordStoreValidateAdaptor::traverseIndex(const IndexAccessMethod* iam,
     *numTraversedKeys = numKeys;
 }
 
+void RecordStoreValidateAdaptor::traverseRecordStore(RecordStore* recordStore,
+                                                     ValidateCmdLevel level,
+                                                     ValidateResults* results,
+                                                     BSONObjBuilder* output) {
+
+    long long nrecords = 0;
+    long long dataSizeTotal = 0;
+    long long nInvalid = 0;
+
+    results->valid = true;
+    std::unique_ptr<SeekableRecordCursor> cursor = recordStore->getCursor(_opCtx, true);
+    int interruptInterval = 4096;
+    RecordId prevRecordId;
+
+    while (auto record = cursor->next()) {
+        ++nrecords;
+
+        if (!(nrecords % interruptInterval)) {
+            _opCtx->checkForInterrupt();
+        }
+
+        auto dataSize = record->data.size();
+        dataSizeTotal += dataSize;
+        size_t validatedSize;
+        Status status = validate(record->id, record->data, &validatedSize);
+
+        // Checks to ensure isInRecordIdOrder() is being used properly.
+        if (prevRecordId.isNormal()) {
+            invariant(prevRecordId < record->id);
+        }
+
+        // While some storage engines, such as MMAPv1, may use padding, we still require
+        // that they return the unpadded record data.
+        if (!status.isOK() || validatedSize != static_cast<size_t>(dataSize)) {
+            if (results->valid) {
+                // Only log once.
+                results->errors.push_back("detected one or more invalid documents (see logs)");
+            }
+            nInvalid++;
+            results->valid = false;
+            log() << "document at location: " << record->id << " is corrupted";
+        }
+
+        prevRecordId = record->id;
+    }
+
+    if (results->valid) {
+        recordStore->updateStatsAfterRepair(_opCtx, nrecords, dataSizeTotal);
+    }
+
+    output->append("nInvalidDocuments", nInvalid);
+    output->appendNumber("nrecords", nrecords);
+}
+
 void RecordStoreValidateAdaptor::validateIndexKeyCount(IndexDescriptor* idx,
                                                        int64_t numRecs,
                                                        ValidateResults& results) {
diff --git a/src/mongo/db/catalog/private/record_store_validate_adaptor.h b/src/mongo/db/catalog/private/record_store_validate_adaptor.h
index cccc4e06254..2cdb21ad429 100644
--- a/src/mongo/db/catalog/private/record_store_validate_adaptor.h
+++ b/src/mongo/db/catalog/private/record_store_validate_adaptor.h
@@ -76,6 +76,15 @@ public:
                        int64_t* numTraversedKeys);
 
     /**
+     * Traverses the record store to retrieve every record and go through its document key
+     * set to keep track of the index consistency during a validation.
+     */
+    void traverseRecordStore(RecordStore* recordStore,
+                             ValidateCmdLevel level,
+                             ValidateResults* results,
+                             BSONObjBuilder* output);
+
+    /**
      * Validate that the number of document keys matches the number of index keys.
      */
     void validateIndexKeyCount(IndexDescriptor* idx, int64_t numRecs, ValidateResults& results);