Import wiredtiger: a901a0e9d7c74f6687f4bb542331a5090fd7a7b2 from branch mongodb-5.0

ref: 99311e58f7..a901a0e9d7
for: 5.0.0-rc1

WT-7320       Add the ability to check database size to the test framework

11 files changed, 186 insertions, 56 deletions

diff --git a/src/third_party/wiredtiger/dist/test_data.py b/src/third_party/wiredtiger/dist/test_data.py
index b13906c22ed..4afefc61497 100644
--- a/src/third_party/wiredtiger/dist/test_data.py
+++ b/src/third_party/wiredtiger/dist/test_data.py
@@ -134,6 +134,9 @@ checkpoint_manager = enabled_config_false + component_config
 runtime_monitor = enabled_config_true + component_config + [
     Config('stat_cache_size', '', '''
         The maximum cache percentage that can be hit while running.''',
+        type='category', subconfig=limit_stat),
+    Config('stat_db_size', '', '''
+        The maximum on-disk database size in bytes that can be hit while running.''',
         type='category', subconfig=limit_stat)
 ]
 
diff --git a/src/third_party/wiredtiger/import.data b/src/third_party/wiredtiger/import.data
index 1fec843d0d4..0af4dc02711 100644
--- a/src/third_party/wiredtiger/import.data
+++ b/src/third_party/wiredtiger/import.data
@@ -2,5 +2,5 @@
     "vendor": "wiredtiger",
     "github": "wiredtiger/wiredtiger.git",
     "branch": "mongodb-5.0",
-    "commit": "99311e58f76242da720219d8bd35127397400b8a"
+    "commit": "a901a0e9d7c74f6687f4bb542331a5090fd7a7b2"
 }
diff --git a/src/third_party/wiredtiger/src/config/test_config.c b/src/third_party/wiredtiger/src/config/test_config.c
index ed314e7e1b3..777b6902a1c 100644
--- a/src/third_party/wiredtiger/src/config/test_config.c
+++ b/src/third_party/wiredtiger/src/config/test_config.c
@@ -11,11 +11,16 @@ static const WT_CONFIG_CHECK confchk_stat_cache_size_subconfigs[] = {
   {"enabled", "boolean", NULL, NULL, NULL, 0}, {"limit", "int", NULL, "min=0", NULL, 0},
   {NULL, NULL, NULL, NULL, NULL, 0}};
 
+static const WT_CONFIG_CHECK confchk_stat_db_size_subconfigs[] = {
+  {"enabled", "boolean", NULL, NULL, NULL, 0}, {"limit", "int", NULL, "min=0", NULL, 0},
+  {NULL, NULL, NULL, NULL, NULL, 0}};
+
 static const WT_CONFIG_CHECK confchk_runtime_monitor_subconfigs[] = {
   {"enabled", "boolean", NULL, NULL, NULL, 0},
   {"interval", "string", NULL, "choices=[\"s\",\"m\",\"h\"]", NULL, 0},
   {"op_count", "int", NULL, "min=1,max=10000", NULL, 0},
   {"stat_cache_size", "category", NULL, NULL, confchk_stat_cache_size_subconfigs, 2},
+  {"stat_db_size", "category", NULL, NULL, confchk_stat_db_size_subconfigs, 2},
   {NULL, NULL, NULL, NULL, NULL, 0}};
 
 static const WT_CONFIG_CHECK confchk_timestamp_manager_subconfigs[] = {
@@ -73,7 +78,7 @@ static const WT_CONFIG_CHECK confchk_example_test[] = {
   {"checkpoint_manager", "category", NULL, NULL, confchk_checkpoint_manager_subconfigs, 3},
   {"duration_seconds", "int", NULL, "min=0,max=1000000", NULL, 0},
   {"enable_logging", "boolean", NULL, NULL, NULL, 0},
-  {"runtime_monitor", "category", NULL, NULL, confchk_runtime_monitor_subconfigs, 4},
+  {"runtime_monitor", "category", NULL, NULL, confchk_runtime_monitor_subconfigs, 5},
   {"timestamp_manager", "category", NULL, NULL, confchk_timestamp_manager_subconfigs, 5},
   {"workload_generator", "category", NULL, NULL, confchk_workload_generator_subconfigs, 10},
   {"workload_tracking", "category", NULL, NULL, confchk_workload_tracking_subconfigs, 3},
@@ -84,7 +89,7 @@ static const WT_CONFIG_CHECK confchk_poc_test[] = {
   {"checkpoint_manager", "category", NULL, NULL, confchk_checkpoint_manager_subconfigs, 3},
   {"duration_seconds", "int", NULL, "min=0,max=1000000", NULL, 0},
   {"enable_logging", "boolean", NULL, NULL, NULL, 0},
-  {"runtime_monitor", "category", NULL, NULL, confchk_runtime_monitor_subconfigs, 4},
+  {"runtime_monitor", "category", NULL, NULL, confchk_runtime_monitor_subconfigs, 5},
   {"timestamp_manager", "category", NULL, NULL, confchk_timestamp_manager_subconfigs, 5},
   {"workload_generator", "category", NULL, NULL, confchk_workload_generator_subconfigs, 10},
   {"workload_tracking", "category", NULL, NULL, confchk_workload_tracking_subconfigs, 3},
@@ -95,7 +100,8 @@ static const WT_CONFIG_ENTRY config_entries[] = {
     "cache_size_mb=0,checkpoint_manager=(enabled=false,interval=s,"
     "op_count=1),duration_seconds=0,enable_logging=false,"
     "runtime_monitor=(enabled=true,interval=s,op_count=1,"
-    "stat_cache_size=(enabled=false,limit=0)),"
+    "stat_cache_size=(enabled=false,limit=0),"
+    "stat_db_size=(enabled=false,limit=0)),"
     "timestamp_manager=(enabled=true,interval=s,oldest_lag=1,"
     "op_count=1,stable_lag=1),workload_generator=(collection_count=1,"
     "enabled=true,insert_config=(interval=s,key_size=5,op_count=1,"
@@ -111,7 +117,8 @@ static const WT_CONFIG_ENTRY config_entries[] = {
     "cache_size_mb=0,checkpoint_manager=(enabled=false,interval=s,"
     "op_count=1),duration_seconds=0,enable_logging=false,"
     "runtime_monitor=(enabled=true,interval=s,op_count=1,"
-    "stat_cache_size=(enabled=false,limit=0)),"
+    "stat_cache_size=(enabled=false,limit=0),"
+    "stat_db_size=(enabled=false,limit=0)),"
     "timestamp_manager=(enabled=true,interval=s,oldest_lag=1,"
     "op_count=1,stable_lag=1),workload_generator=(collection_count=1,"
     "enabled=true,insert_config=(interval=s,key_size=5,op_count=1,"
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/runtime_monitor.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/runtime_monitor.h
index d24317b7352..90aecc9aa59 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/runtime_monitor.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/runtime_monitor.h
@@ -38,6 +38,7 @@ extern "C" {
 #include "core/component.h"
 #include "core/throttle.h"
 #include "connection_manager.h"
+#include "workload/database_operation.h"
 
 namespace test_harness {
 /* Static statistic get function. */
@@ -52,7 +53,7 @@ get_stat(WT_CURSOR *cursor, int stat_field, int64_t *valuep)
 
 class statistic {
     public:
-    statistic(configuration *config)
+    explicit statistic(configuration *config)
     {
         _enabled = config->get_bool(ENABLED);
     }
@@ -75,13 +76,13 @@ class statistic {
 
 class cache_limit_statistic : public statistic {
     public:
-    cache_limit_statistic(configuration *config) : statistic(config)
+    explicit cache_limit_statistic(configuration *config) : statistic(config)
     {
         limit = config->get_int(LIMIT);
     }
 
     void
-    check(WT_CURSOR *cursor)
+    check(WT_CURSOR *cursor) override final
     {
         testutil_assert(cursor != nullptr);
         int64_t cache_bytes_image, cache_bytes_other, cache_bytes_max;
@@ -96,11 +97,10 @@ class cache_limit_statistic : public statistic {
          */
         use_percent = ((cache_bytes_image + cache_bytes_other + 0.0) / cache_bytes_max) * 100;
         if (use_percent > limit) {
-            std::string error_string =
+            const std::string error_string =
               "runtime_monitor: Cache usage exceeded during test! Limit: " + std::to_string(limit) +
               " usage: " + std::to_string(use_percent);
-            debug_print(error_string, DEBUG_ERROR);
-            testutil_assert(use_percent < limit);
+            testutil_die(-1, error_string.c_str());
         } else
             debug_print("Cache usage: " + std::to_string(use_percent), DEBUG_TRACE);
     }
@@ -109,13 +109,89 @@ class cache_limit_statistic : public statistic {
     int64_t limit;
 };
 
+static std::string
+collection_name_to_file_name(const std::string &collection_name)
+{
+    /* Strip out the URI prefix. */
+    const size_t colon_pos = collection_name.find(':');
+    testutil_assert(colon_pos != std::string::npos);
+    const auto stripped_name = collection_name.substr(colon_pos + 1);
+
+    /* Now add the directory and file extension. */
+    return std::string(DEFAULT_DIR) + "/" + stripped_name + ".wt";
+}
+
+class db_size_statistic : public statistic {
+    public:
+    db_size_statistic(configuration *config, database &database)
+        : statistic(config), _database(database)
+    {
+        _limit = config->get_int(LIMIT);
+#ifdef _WIN32
+        debug_print("Database size checking is not implemented on Windows", DEBUG_ERROR);
+#endif
+    }
+    virtual ~db_size_statistic() = default;
+
+    /* Don't need the stat cursor for this. */
+    void
+    check(WT_CURSOR *) override final
+    {
+        const auto file_names = get_file_names();
+#ifndef _WIN32
+        size_t db_size = 0;
+        for (const auto &name : file_names) {
+            struct stat sb;
+            if (stat(name.c_str(), &sb) == 0) {
+                db_size += sb.st_size;
+                debug_print(name + " was " + std::to_string(sb.st_size) + " bytes", DEBUG_TRACE);
+            } else
+                /* The only good reason for this to fail is if the file hasn't been created yet. */
+                testutil_assert(errno == ENOENT);
+        }
+        debug_print("Current database size is " + std::to_string(db_size) + " bytes", DEBUG_TRACE);
+        if (db_size > _limit) {
+            const std::string error_string =
+              "runtime_monitor: Database size limit exceeded during test! Limit: " +
+              std::to_string(_limit) + " db size: " + std::to_string(db_size);
+            testutil_die(-1, error_string.c_str());
+        }
+#else
+        static_cast<void>(file_names);
+        static_cast<void>(_database);
+        static_cast<void>(_limit);
+#endif
+    }
+
+    private:
+    std::vector<std::string>
+    get_file_names()
+    {
+        std::vector<std::string> file_names;
+        for (const auto &name : _database.get_collection_names())
+            file_names.push_back(collection_name_to_file_name(name));
+
+        /* Add WiredTiger internal tables. */
+        file_names.push_back(std::string(DEFAULT_DIR) + "/" + WT_HS_FILE);
+        file_names.push_back(std::string(DEFAULT_DIR) + "/" + WT_METAFILE);
+
+        return file_names;
+    }
+
+    database &_database;
+    int64_t _limit;
+};
+
 /*
  * The runtime monitor class is designed to track various statistics or other runtime signals
  * relevant to the given workload.
  */
 class runtime_monitor : public component {
     public:
-    runtime_monitor(configuration *config) : component("runtime_monitor", config) {}
+    runtime_monitor(configuration *config, database &database)
+        : component("runtime_monitor", config), _database(database)
+    {
+    }
 
     ~runtime_monitor()
     {
@@ -147,6 +223,10 @@ class runtime_monitor : public component {
             sub_config = _config->get_subconfig(STAT_CACHE_SIZE);
             _stats.push_back(new cache_limit_statistic(sub_config));
             delete sub_config;
+
+            sub_config = _config->get_subconfig(STAT_DB_SIZE);
+            _stats.push_back(new db_size_statistic(sub_config, _database));
+            delete sub_config;
         }
     }
 
@@ -163,6 +243,7 @@ class runtime_monitor : public component {
     WT_CURSOR *_cursor = nullptr;
     WT_SESSION *_session = nullptr;
     std::vector<statistic *> _stats;
+    database &_database;
 };
 } // namespace test_harness
 
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/test.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/test.h
index 06337d2a000..2434704f6f9 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/test.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/test.h
@@ -59,13 +59,13 @@ class test : public database_operation {
     {
         _config = new configuration(name, config);
         _checkpoint_manager = new checkpoint_manager(_config->get_subconfig(CHECKPOINT_MANAGER));
-        _runtime_monitor = new runtime_monitor(_config->get_subconfig(RUNTIME_MONITOR));
+        _runtime_monitor = new runtime_monitor(_config->get_subconfig(RUNTIME_MONITOR), _database);
         _timestamp_manager = new timestamp_manager(_config->get_subconfig(TIMESTAMP_MANAGER));
         _workload_tracking = new workload_tracking(_config->get_subconfig(WORKLOAD_TRACKING),
           OPERATION_TRACKING_TABLE_CONFIG, TABLE_OPERATION_TRACKING, SCHEMA_TRACKING_TABLE_CONFIG,
           TABLE_SCHEMA_TRACKING);
-        _workload_generator = new workload_generator(
-          _config->get_subconfig(WORKLOAD_GENERATOR), this, _timestamp_manager, _workload_tracking);
+        _workload_generator = new workload_generator(_config->get_subconfig(WORKLOAD_GENERATOR),
+          this, _timestamp_manager, _workload_tracking, _database);
         _thread_manager = new thread_manager();
         /*
          * Ordering is not important here, any dependencies between components should be resolved
@@ -191,6 +191,7 @@ class test : public database_operation {
     timestamp_manager *_timestamp_manager = nullptr;
     workload_generator *_workload_generator = nullptr;
     workload_tracking *_workload_tracking = nullptr;
+    database _database;
 };
 } // namespace test_harness
 
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/util/api_const.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/util/api_const.h
index 495989407c1..51200d389c9 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/util/api_const.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/util/api_const.h
@@ -58,6 +58,7 @@ static const char *OPS_PER_TRANSACTION = "ops_per_transaction";
 static const char *READ_CONFIG = "read_config";
 static const char *STABLE_LAG = "stable_lag";
 static const char *STAT_CACHE_SIZE = "stat_cache_size";
+static const char *STAT_DB_SIZE = "stat_db_size";
 static const char *THREAD_COUNT = "thread_count";
 static const char *UPDATE_CONFIG = "update_config";
 static const char *VALUE_SIZE = "value_size";
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_model.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_model.h
index c2a7ed9f6a6..c9562954bfd 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_model.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_model.h
@@ -50,24 +50,77 @@ struct value_t {
 /* A collection is made of mapped Key objects. */
 struct collection_t {
     std::map<key_value_t, key_t> keys;
-    std::map<key_value_t, value_t> *values = {nullptr};
+    std::map<key_value_t, value_t> values;
 };
 
 /* Representation of the collections in memory. */
 class database {
     public:
-    const std::vector<std::string>
-    get_collection_names() const
+    std::vector<std::string>
+    get_collection_names()
     {
+        std::lock_guard<std::mutex> lg(_mtx);
         std::vector<std::string> collection_names;
 
-        for (auto const &it : collections)
+        for (auto const &it : _collections)
             collection_names.push_back(it.first);
 
         return (collection_names);
     }
 
-    std::map<std::string, collection_t> collections;
+    std::map<key_value_t, key_t>
+    get_keys(const std::string &collection_name)
+    {
+        std::lock_guard<std::mutex> lg(_mtx);
+        return (_collections.at(collection_name).keys);
+    }
+
+    void
+    add_collection(const std::string &collection_name)
+    {
+        std::lock_guard<std::mutex> lg(_mtx);
+        testutil_assert(_collections.find(collection_name) == _collections.end());
+        _collections[collection_name] = {};
+    }
+
+    value_t
+    get_record(const std::string &collection_name, const char *key)
+    {
+        std::lock_guard<std::mutex> lg(_mtx);
+        return (_collections.at(collection_name).values.at(key));
+    }
+
+    void
+    insert_record(const std::string &collection_name, const char *key, const char *value)
+    {
+        std::lock_guard<std::mutex> lg(_mtx);
+        auto &c = _collections.at(collection_name);
+        c.keys[key].exists = true;
+        value_t v;
+        v.value = key_value_t(value);
+        c.values.emplace(key_value_t(key), v);
+    }
+
+    void
+    update_record(const std::string &collection_name, const char *key, const char *value)
+    {
+        std::lock_guard<std::mutex> lg(_mtx);
+        auto &c = _collections.at(collection_name);
+        c.values.at(key).value = key_value_t(value);
+    }
+
+    void
+    delete_record(const std::string &collection_name, const char *key)
+    {
+        std::lock_guard<std::mutex> lg(_mtx);
+        auto &c = _collections.at(collection_name);
+        c.keys.at(key).exists = false;
+        c.values.erase(key);
+    }
+
+    private:
+    std::map<std::string, collection_t> _collections;
+    std::mutex _mtx;
 };
 } // namespace test_harness
 
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_operation.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_operation.h
index ab192f798b1..007d39da345 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_operation.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/database_operation.h
@@ -69,7 +69,7 @@ class database_operation {
         collection_count = config->get_int(COLLECTION_COUNT);
         for (size_t i = 0; i < collection_count; ++i) {
             collection_name = "table:collection" + std::to_string(i);
-            database.collections[collection_name] = {};
+            database.add_collection(collection_name);
             testutil_check(
               session->create(session, collection_name.c_str(), DEFAULT_FRAMEWORK_SCHEMA));
             ts = timestamp_manager->get_next_ts();
@@ -87,8 +87,7 @@ class database_operation {
         /* Keys must be unique. */
         testutil_assert(key_count <= pow(10, key_size));
 
-        for (const auto &it_collections : database.collections) {
-            collection_name = it_collections.first;
+        for (const auto &collection_name : database.get_collection_names()) {
             key_cpt = 0;
             /*
              * WiredTiger lets you open a cursor on a collection using the same pointer. When a
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/thread_context.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/thread_context.h
index 47f0453512d..63291ac9756 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/thread_context.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/thread_context.h
@@ -30,6 +30,7 @@
 #define THREAD_CONTEXT_H
 
 #include "../core/throttle.h"
+#include "../timestamp_manager.h"
 #include "database_model.h"
 #include "random_generator.h"
 #include "workload_tracking.h"
@@ -153,7 +154,7 @@ class thread_context {
     transaction_context transaction;
     test_harness::timestamp_manager *timestamp_manager;
     test_harness::workload_tracking *tracking;
-    test_harness::database database;
+    test_harness::database &database;
     int64_t key_size = 0;
     int64_t value_size = 0;
 
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/workload_validation.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/workload_validation.h
index aaab9ad25a9..7f583a66888 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/workload_validation.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload/workload_validation.h
@@ -120,11 +120,7 @@ class workload_validation {
                  * The data model is now fully updated for the last read collection. It can be
                  * checked.
                  */
-                check_reference(session, collection_name, database.collections.at(collection_name));
-                /* Clear memory. */
-                delete database.collections[collection_name].values;
-                database.collections[collection_name].values = nullptr;
-
+                check_reference(session, collection_name, database);
                 collection_name = key_collection_name;
             }
         };
@@ -139,12 +135,8 @@ class workload_validation {
          * empty if there is no collections to check after the end of the test (no collections
          * created or all deleted).
          */
-        if (!collection_name.empty()) {
-            check_reference(session, collection_name, database.collections.at(collection_name));
-            /* Clear memory. */
-            delete database.collections[collection_name].values;
-            database.collections[collection_name].values = nullptr;
-        }
+        if (!collection_name.empty())
+            check_reference(session, collection_name, database);
     }
 
     private:
@@ -200,25 +192,17 @@ class workload_validation {
              * the key has been inserted previously in an existing collection and can be safely
              * deleted.
              */
-            database.collections.at(collection_name).keys.at(key).exists = false;
-            delete database.collections.at(collection_name).values;
-            database.collections.at(collection_name).values = nullptr;
+            database.delete_record(collection_name, key);
             break;
         case tracking_operation::INSERT: {
             /*
              * Keys are unique, it is safe to assume the key has not been encountered before.
              */
-            database.collections[collection_name].keys[key].exists = true;
-            if (database.collections[collection_name].values == nullptr)
-                database.collections[collection_name].values = new std::map<key_value_t, value_t>();
-            value_t v;
-            v.value = key_value_t(value);
-            std::pair<key_value_t, value_t> pair(key_value_t(key), v);
-            database.collections[collection_name].values->insert(pair);
+            database.insert_record(collection_name, key, value);
             break;
         }
         case tracking_operation::UPDATE:
-            database.collections[collection_name].values->at(key).value = key_value_t(value);
+            database.update_record(collection_name, key, value);
             break;
         default:
             testutil_die(DEBUG_ERROR, "Unexpected operation in the tracking table: %d",
@@ -232,8 +216,7 @@ class workload_validation {
      * representation in memory of the collection values and keys according to the tracking table.
      */
     void
-    check_reference(
-      WT_SESSION *session, const std::string &collection_name, const collection_t &collection)
+    check_reference(WT_SESSION *session, const std::string &collection_name, database &database)
     {
         bool is_valid;
         key_t key;
@@ -247,7 +230,7 @@ class workload_validation {
               collection_name.c_str());
 
         /* Walk through each key/value pair of the current collection. */
-        for (const auto &keys : collection.keys) {
+        for (const auto &keys : database.get_keys(collection_name)) {
             key_str = keys.first;
             key = keys.second;
             /* The key/value pair exists. */
@@ -263,12 +246,12 @@ class workload_validation {
 
             /* Check the associated value is valid. */
             if (key.exists) {
-                testutil_assert(collection.values != nullptr);
                 if (!verify_value(session, collection_name, key_str.c_str(),
-                      collection.values->at(key_str).value))
+                      database.get_record(collection_name, key_str.c_str()).value))
                     testutil_die(DEBUG_ERROR,
                       "check_reference: failed for key %s / value %s in collection %s.",
-                      key_str.c_str(), collection.values->at(key_str).value.c_str(),
+                      key_str.c_str(),
+                      database.get_record(collection_name, key_str.c_str()).value.c_str(),
                       collection_name.c_str());
             }
         }
diff --git a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload_generator.h b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload_generator.h
index bc7b0c45c03..1980cf6ac6c 100644
--- a/src/third_party/wiredtiger/test/cppsuite/test_harness/workload_generator.h
+++ b/src/third_party/wiredtiger/test/cppsuite/test_harness/workload_generator.h
@@ -46,9 +46,10 @@ namespace test_harness {
 class workload_generator : public component {
     public:
     workload_generator(configuration *configuration, database_operation *db_operation,
-      timestamp_manager *timestamp_manager, workload_tracking *tracking)
-        : component("workload_generator", configuration), _database_operation(db_operation),
-          _timestamp_manager(timestamp_manager), _tracking(tracking)
+      timestamp_manager *timestamp_manager, workload_tracking *tracking, database &database)
+        : component("workload_generator", configuration), _database(database),
+          _database_operation(db_operation), _timestamp_manager(timestamp_manager),
+          _tracking(tracking)
     {
     }
 
@@ -123,7 +124,7 @@ class workload_generator : public component {
     }
 
     private:
-    database _database;
+    database &_database;
     database_operation *_database_operation;
     thread_manager _thread_manager;
     timestamp_manager *_timestamp_manager;