This should fix the races while accessing the relation statistics inside dbb_stats. Reads/writes/fetches/marks are incremented (CCH) and read (INF) unprotected, as it's crash safe and read skews are acceptable. Other counters (both global and relation wise) are protected with a mutex. They're incremented on demand based on the attachment counters (via diffs). While being there, cleaned up the currently unused performance counters.

src/jrd/Attachment.cpp

@@ -179,6 +179,7 @@ Jrd::Attachment::Attachment(MemoryPool* pool, Database* dbb)
 	  att_lock_owner_id(Database::getLockOwnerId()),
 	  att_backup_state_counter(0),
 	  att_stats(*pool),
+	  att_base_stats(*pool),
 	  att_working_directory(*pool),
 	  att_filename(*pool),
 	  att_timestamp(Firebird::TimeStamp::getCurrentTimeStamp()),
@@ -381,6 +382,14 @@ void Jrd::Attachment::signalShutdown()
 }
 
 
+void Jrd::Attachment::mergeStats()
+{
+	MutexLockGuard guard(att_database->dbb_stats_mutex, FB_FUNCTION);
+	att_database->dbb_stats.adjust(att_base_stats, att_stats, true);
+	att_base_stats.assign(att_stats);
+}
+
+
 // Find an inactive incarnation of a system request. If necessary, clone it.
 jrd_req* Jrd::Attachment::findSystemRequest(thread_db* tdbb, USHORT id, USHORT which)
 {

src/jrd/Attachment.h

@@ -250,6 +250,7 @@ public:
 	SecurityClass*	att_security_class;		// security class for database
 	SecurityClassList*	att_security_classes;	// security classes
 	RuntimeStatistics	att_stats;
+	RuntimeStatistics	att_base_stats;
 	ULONG		att_flags;					// Flags describing the state of the attachment
 	SSHORT		att_client_charset;			// user's charset specified in dpb
 	SSHORT		att_charset;				// current (client or external) attachment charset
@@ -355,6 +356,8 @@ public:
 	void signalCancel();
 	void signalShutdown();
 
+	void mergeStats();
+
 	bool backupStateWriteLock(thread_db* tdbb, SSHORT wait);
 	void backupStateWriteUnLock(thread_db* tdbb);
 	bool backupStateReadLock(thread_db* tdbb, SSHORT wait);

src/jrd/Database.h

@@ -447,8 +447,9 @@ public:
 	Firebird::Semaphore dbb_gc_fini;	// Event for finalization garbage collector
 
 	Firebird::MemoryStats dbb_memory_stats;
-
 	RuntimeStatistics dbb_stats;
+	mutable Firebird::Mutex dbb_stats_mutex;
+
 	TraNumber	dbb_last_header_write;	// Transaction id of last header page physical write
 	SLONG dbb_flush_cycle;				// Current flush cycle
 	ULONG dbb_sweep_interval;			// Transactions between sweep

src/jrd/JrdStatement.cpp

@@ -281,8 +281,6 @@ JrdStatement* JrdStatement::makeStatement(thread_db* tdbb, CompilerScratch* csb,
 
 	if (internalFlag)
 		statement->flags |= FLAG_INTERNAL;
-	else
-		tdbb->bumpStats(RuntimeStatistics::STMT_PREPARES);
 
 	return statement;
 }

src/jrd/Monitoring.cpp

@@ -786,6 +786,7 @@ void Monitoring::putDatabase(SnapshotData::DumpRecord& record, const Database* d
 
 	if (database->dbb_flags & DBB_shared)
 	{
+		MutexLockGuard guard(database->dbb_stats_mutex, FB_FUNCTION);
 		putStatistics(record, database->dbb_stats, writer, stat_id, stat_database);
 		putMemoryUsage(record, database->dbb_memory_stats, writer, stat_id, stat_database);
 	}
@@ -876,6 +877,7 @@ void Monitoring::putAttachment(SnapshotData::DumpRecord& record, const Jrd::Atta
 	}
 	else
 	{
+		MutexLockGuard guard(attachment->att_database->dbb_stats_mutex, FB_FUNCTION);
 		putStatistics(record, attachment->att_database->dbb_stats, writer, stat_id, stat_attachment);
 		putMemoryUsage(record, attachment->att_database->dbb_memory_stats, writer, stat_id, stat_attachment);
 	}
@@ -1182,7 +1184,7 @@ void Monitoring::checkState(thread_db* tdbb)
 }
 
 
-void Monitoring::dumpAttachment(thread_db* tdbb, const Attachment* attachment, bool ast)
+void Monitoring::dumpAttachment(thread_db* tdbb, Attachment* attachment, bool ast)
 {
 	if (!attachment->att_user)
 		return;
@@ -1190,6 +1192,8 @@ void Monitoring::dumpAttachment(thread_db* tdbb, const Attachment* attachment, b
 	Database* const dbb = tdbb->getDatabase();
 	MemoryPool& pool = *dbb->dbb_permanent;
 
+	attachment->mergeStats();
+
 	const AttNumber att_id = attachment->att_attachment_id;
 	const string& user_name = attachment->att_user->usr_user_name;
 

src/jrd/Monitoring.h

@@ -385,7 +385,7 @@ public:
 	static void checkState(thread_db* tdbb);
 	static SnapshotData* getSnapshot(thread_db* tdbb);
 
-	static void dumpAttachment(thread_db* tdbb, const Attachment* attachment, bool ast);
+	static void dumpAttachment(thread_db* tdbb, Attachment* attachment, bool ast);
 
 	static void publishAttachment(thread_db* tdbb);
 	static void cleanupAttachment(thread_db* tdbb);

src/jrd/RuntimeStatistics.h

@@ -50,7 +50,6 @@ public:
 		PAGE_READS,
 		PAGE_MARKS,
 		PAGE_WRITES,
-		FLUSHES,
 		RECORD_SEQ_READS,
 		RECORD_IDX_READS,
 		RECORD_UPDATES,
@@ -65,23 +64,18 @@ public:
 		RECORD_BACKVERSION_READS,
 		RECORD_FRAGMENT_READS,
 		RECORD_RPT_READS,
-		SORTS,
-		SORT_GETS,
-		SORT_PUTS,
-		STMT_PREPARES,
-		STMT_EXECUTES,
 		TOTAL_ITEMS		// last
 	};
 
+private:
+	static const size_t REL_BASE_OFFSET = RECORD_SEQ_READS;
+	static const size_t REL_TOTAL_ITEMS = RECORD_RPT_READS - REL_BASE_OFFSET + 1;
+
 	// Performance counters for individual table
 
 	class RelationCounts
 	{
-		static const size_t REL_BASE_OFFSET = RECORD_SEQ_READS;
-
 	public:
-		static const size_t REL_TOTAL_ITEMS = RECORD_RPT_READS - REL_BASE_OFFSET + 1;
-
 		explicit RelationCounts(SLONG relation_id)
 			: rlc_relation_id(relation_id)
 		{
@@ -158,6 +152,7 @@ public:
 	typedef Firebird::SortedArray<RelationCounts, Firebird::EmptyStorage<RelationCounts>,
 		SLONG, RelationCounts> RelCounters;
 
+public:
 	RuntimeStatistics()
 		: Firebird::AutoStorage(), rel_counts(getPool())
 	{
@@ -226,12 +221,14 @@ public:
 
 	// add difference between newStats and baseStats to our counters
 	// newStats and baseStats must be "in-sync"
-	void adjust(const RuntimeStatistics& baseStats, const RuntimeStatistics& newStats)
+	void adjust(const RuntimeStatistics& baseStats, const RuntimeStatistics& newStats, bool relStatsOnly = false)
 	{
 		if (baseStats.allChgNumber != newStats.allChgNumber)
 		{
+			const size_t FIRST_ITEM = relStatsOnly ? REL_BASE_OFFSET : 0;
+
 			allChgNumber++;
-			for (size_t i = 0; i < TOTAL_ITEMS; ++i)
+			for (size_t i = FIRST_ITEM; i < TOTAL_ITEMS; ++i)
 				values[i] += newStats.values[i] - baseStats.values[i];
 
 			if (baseStats.relChgNumber != newStats.relChgNumber)

src/jrd/cch.cpp

@@ -1037,8 +1037,6 @@ void CCH_flush(thread_db* tdbb, USHORT flush_flag, TraNumber tra_number)
 			if (backup_state == Ods::hdr_nbak_stalled || backup_state == Ods::hdr_nbak_merge)
 				bm->flushDifference(tdbb);
 		}
-
-		tdbb->bumpStats(RuntimeStatistics::FLUSHES);
 	}
 
 	// take the opportunity when we know there are no pages

src/jrd/exe.cpp

@@ -902,9 +902,6 @@ void EXE_start(thread_db* tdbb, jrd_req* request, jrd_tra* transaction)
 		impure->vlu_flags = 0;
 	}
 
-	if (statement->sqlText)
-		tdbb->bumpStats(RuntimeStatistics::STMT_EXECUTES);
-
 	request->req_src_line = 0;
 	request->req_src_column = 0;
 

src/jrd/jrd.cpp

@@ -6358,6 +6358,8 @@ static void release_attachment(thread_db* tdbb, Jrd::Attachment* attachment)
 		attachment->deletePool(pool);
 	}
 
+	attachment->mergeStats();
+
 	// remove the attachment block from the dbb linked list
 	Sync sync(&dbb->dbb_sync, "jrd.cpp: release_attachment");
 	sync.lock(SYNC_EXCLUSIVE);
@@ -7399,17 +7401,13 @@ void thread_db::setDatabase(Database* val)
 		const bool wasActive = database && (priorThread || nextThread || database->dbb_active_threads == this);
 
 		if (wasActive)
-		{
 			deactivate();
-		}
 
 		database = val;
 		dbbStat = val ? &val->dbb_stats : RuntimeStatistics::getDummy();
 
 		if (wasActive)
-		{
 			activate();
-		}
 	}
 }
 

src/jrd/jrd.h

@@ -459,12 +459,30 @@ public:
 
 	void bumpRelStats(const RuntimeStatistics::StatType index, SLONG relation_id, SINT64 delta = 1)
 	{
-		bumpStats(index, delta);
+		// We don't bump counters for dbbStat here, they're merged from attStats on demand
 
-		reqStat->bumpRelValue(index, relation_id, delta);
-		traStat->bumpRelValue(index, relation_id, delta);
-		attStat->bumpRelValue(index, relation_id, delta);
-		dbbStat->bumpRelValue(index, relation_id, delta);
+		reqStat->bumpValue(index, delta);
+		traStat->bumpValue(index, delta);
+		attStat->bumpValue(index, delta);
+
+		const RuntimeStatistics* const dummyStat = RuntimeStatistics::getDummy();
+
+		// We expect that at least attStat is present (not a dummy object)
+
+		fb_assert(attStat != dummyStat);
+
+		// Relation statistics is a quite complex beast, so a conditional check
+		// does not hurt. It also allows to avoid races while accessing the static
+		// dummy object concurrently.
+
+		if (reqStat != dummyStat)
+			reqStat->bumpRelValue(index, relation_id, delta);
+
+		if (traStat != dummyStat)
+			traStat->bumpRelValue(index, relation_id, delta);
+
+		if (attStat != dummyStat)
+			attStat->bumpRelValue(index, relation_id, delta);
 	}
 
 	ISC_STATUS checkCancelState();

src/jrd/sort.cpp

@@ -342,8 +342,6 @@ void Sort::get(thread_db* tdbb, ULONG** record_address)
 		{
 			diddleKey((UCHAR*) record->sort_record_key, false);
 		}
-
-		tdbb->bumpStats(RuntimeStatistics::SORT_GETS);
 	}
 	catch (const BadAlloc&)
 	{
@@ -419,8 +417,6 @@ void Sort::put(thread_db* tdbb, ULONG** record_address)
 		*m_next_pointer++ = reinterpret_cast<sort_record*>(record->sr_sort_record.sort_record_key);
 		m_records++;
 		*record_address = (ULONG*) record->sr_sort_record.sort_record_key;
-
-		tdbb->bumpStats(RuntimeStatistics::SORT_PUTS);
 	}
 	catch (const BadAlloc&)
 	{
@@ -463,7 +459,6 @@ void Sort::sort(thread_db* tdbb)
 			sort();
 			m_next_pointer = m_first_pointer + 1;
 			m_flags |= scb_sorted;
-			tdbb->bumpStats(RuntimeStatistics::SORTS);
 			return;
 		}
 
@@ -619,7 +614,6 @@ void Sort::sort(thread_db* tdbb)
 		sortRunsBySeek(run_count);
 
 		m_flags |= scb_sorted;
-		tdbb->bumpStats(RuntimeStatistics::SORTS);
 	}
 	catch (const BadAlloc&)
 	{