Added comments to specify why no much mutex is needed. (7f3f9027) · Commits · Software / OSDI20 Artifacts / mariadb

sql/ha_heap.cc

+24 −0

Original line number	Diff line number	Diff line
		@@ -142,7 +142,13 @@ int ha_heap::write_row(byte * buf)
		res= heap_write(file,buf);
		if (!res && ++records_changed*HEAP_STATS_UPDATE_THRESHOLD >
		file->s->records)
		{
		/*
		We can perform this safely since only one writer at the time is
		allowed on the table.
		*/
		file->s->key_stat_version++;
		}
		return res;
		}

		@@ -155,7 +161,13 @@ int ha_heap::update_row(const byte * old_data, byte * new_data)
		res= heap_update(file,old_data,new_data);
		if (!res && ++records_changed*HEAP_STATS_UPDATE_THRESHOLD >
		file->s->records)
		{
		/*
		We can perform this safely since only one writer at the time is
		allowed on the table.
		*/
		file->s->key_stat_version++;
		}
		return res;
		}

		@@ -166,7 +178,13 @@ int ha_heap::delete_row(const byte * buf)
		res= heap_delete(file,buf);
		if (!res && table->tmp_table == NO_TMP_TABLE &&
		++records_changed*HEAP_STATS_UPDATE_THRESHOLD > file->s->records)
		{
		/*
		We can perform this safely since only one writer at the time is
		allowed on the table.
		*/
		file->s->key_stat_version++;
		}
		return res;
		}

		@@ -297,7 +315,13 @@ int ha_heap::delete_all_rows()
		{
		heap_clear(file);
		if (table->tmp_table == NO_TMP_TABLE)
		{
		/*
		We can perform this safely since only one writer at the time is
		allowed on the table.
		*/
		file->s->key_stat_version++;
		}
		return 0;
		}