Fix 'conditional jump or move depends on uninitialised value(s)' detected by Valgrind

[JavierJF]

• A clear description of the issue

Valgrind reported a series of 'conditional jump or move depends on uninitialised value(s)' during testing, relevant ones include:

==961522== 4 errors in context 18 of 55:
==961522== Conditional jump or move depends on uninitialised value(s)
==961522==    at 0x8C84EB: Command_Counter::_add_idx(unsigned long long) (query_processor.h:213)
==961522==    by 0x8C875B: Command_Counter::add_time(unsigned long long) (query_processor.h:240)
==961522==    by 0x8C13FA: Query_Processor::query_parser_update_counters(MySQL_Session*, MYSQL_COM_QUERY_command, __SQP_query_parser_t*, unsigned long long) (Query_Processor.cpp:1906)
==961522==    by 0x8479A5: Query_Info::query_parser_update_counters() (MySQL_Session.cpp:304)
==961522==    by 0x847457: Query_Info::end() (MySQL_Session.cpp:249)
==961522==    by 0x885A1F: MySQL_Session::RequestEnd(MySQL_Data_Stream*) (MySQL_Session.cpp:6773)
==961522==    by 0x86F8C4: MySQL_Session::handler() (MySQL_Session.cpp:4565)
==961522==    by 0x8168A8: MySQL_Thread::process_all_sessions() (MySQL_Thread.cpp:4927)
==961522==    by 0x813469: MySQL_Thread::run() (MySQL_Thread.cpp:4445)
==961522==    by 0x6AEFB0: mysql_worker_thread_func(void*) (main.cpp:789)
==961522==    by 0x4A78298: start_thread (in /usr/lib/libpthread-2.33.so)
==961522==    by 0x4EF9052: clone (in /usr/lib/libc-2.33.so)
==961522==  Uninitialised value was created by a heap allocation
==961522==    at 0x483E77F: malloc (vg_replace_malloc.c:307)
==961522==    by 0x84801D: MySQL_Session::operator new(unsigned long) (MySQL_Session.cpp:421)
==961522==    by 0x80F9E7: MySQL_Thread::create_new_session_and_client_data_stream(int) (MySQL_Thread.cpp:3958)
==961522==    by 0x819F0F: MySQL_Thread::listener_handle_new_connection(MySQL_Data_Stream*, unsigned int) (MySQL_Thread.cpp:5245)
==961522==    by 0x811D18: MySQL_Thread::ProcessAllMyDS_AfterPoll() (MySQL_Thread.cpp:4185)
==961522==    by 0x8132F5: MySQL_Thread::run() (MySQL_Thread.cpp:4429)
==961522==    by 0x6AEFB0: mysql_worker_thread_func(void*) (main.cpp:789)
==961522==    by 0x4A78298: start_thread (in /usr/lib/libpthread-2.33.so)
==961522==    by 0x4EF9052: clone (in /usr/lib/libc-2.33.so)
==961522== 
==961522== 
==961522== 54 errors in context 19 of 55:
==961522== Thread 12:
==961522== Conditional jump or move depends on uninitialised value(s)
==961522==    at 0x8B1D9B: QP_query_digest_stats::add_time(unsigned long long, unsigned long long, unsigned long long, unsigned long long) (Query_Processor.cpp:191)
==961522==    by 0x8C208B: Query_Processor::update_query_digest(__SQP_query_parser_t*, int, MySQL_Connection_userinfo*, unsigned long long, unsigned long long, MySQL_STMT_Global_info*, MySQL_Session*) (Query_Processor.cpp:1978)
==961522==    by 0x8C194D: Query_Processor::query_parser_update_counters(MySQL_Session*, MYSQL_COM_QUERY_command, __SQP_query_parser_t*, unsigned long long) (Query_Processor.cpp:1935)
==961522==    by 0x8479A5: Query_Info::query_parser_update_counters() (MySQL_Session.cpp:304)
==961522==    by 0x847457: Query_Info::end() (MySQL_Session.cpp:249)
==961522==    by 0x885A1F: MySQL_Session::RequestEnd(MySQL_Data_Stream*) (MySQL_Session.cpp:6773)
==961522==    by 0x86F8C4: MySQL_Session::handler() (MySQL_Session.cpp:4565)
==961522==    by 0x8168A8: MySQL_Thread::process_all_sessions() (MySQL_Thread.cpp:4927)
==961522==    by 0x813469: MySQL_Thread::run() (MySQL_Thread.cpp:4445)
==961522==    by 0x6AEFB0: mysql_worker_thread_func(void*) (main.cpp:789)
==961522==    by 0x4A78298: start_thread (in /usr/lib/libpthread-2.33.so)
==961522==    by 0x4EF9052: clone (in /usr/lib/libc-2.33.so)
==961522==  Uninitialised value was created by a heap allocation
==961522==    at 0x483E77F: malloc (vg_replace_malloc.c:307)
==961522==    by 0x84801D: MySQL_Session::operator new(unsigned long) (MySQL_Session.cpp:421)
==961522==    by 0x80F9E7: MySQL_Thread::create_new_session_and_client_data_stream(int) (MySQL_Thread.cpp:3958)
==961522==    by 0x819F0F: MySQL_Thread::listener_handle_new_connection(MySQL_Data_Stream*, unsigned int) (MySQL_Thread.cpp:5245)
==961522==    by 0x811D18: MySQL_Thread::ProcessAllMyDS_AfterPoll() (MySQL_Thread.cpp:4185)
==961522==    by 0x8132F5: MySQL_Thread::run() (MySQL_Thread.cpp:4429)
==961522==    by 0x6AEFB0: mysql_worker_thread_func(void*) (main.cpp:789)
==961522==    by 0x4A78298: start_thread (in /usr/lib/libpthread-2.33.so)
==961522==    by 0x4EF9052: clone (in /usr/lib/libc-2.33.so)

• ProxySQL version

• v2.1.1

• OS version

NAME="Arch Linux"
PRETTY_NAME="Arch Linux"
ID=arch
BUILD_ID=rolling

• The steps to reproduce the issue

To reproduce the behavior it's required to create a flow in which the variables:

	unsigned long long start_time;
	unsigned long long end_time;

Remains uninitialized when are being accessed for counter update.

• Full valgrind log

valgrind-log-3458.txt