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MXS-2521: Detect COM_STMT_EXECUTE without metadata

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If a COM_STMT_EXECUTE has no metadata in it and it has more than one
parameter, it must be routed to the same backend where the previous
COM_STMT_EXECUTE with the same ID was routed to. This prevents MDEV-19811
that is triggered by MaxScale routing the queries to different backends.
This commit is contained in:
Markus Mäkelä
2019-06-26 12:33:46 +03:00
parent a6617f52fc
commit 5eba688c1b
4 changed files with 105 additions and 12 deletions
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85
server/core/queryclassifier.cc
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@ -75,6 +75,19 @@ uint32_t qc_mysql_extract_ps_id(GWBUF* buffer)
return rval;
}
uint16_t qc_extract_ps_param_count(GWBUF* buffer)
{
uint16_t rval = 0;
uint8_t params[MYSQL_PS_PARAMS_SIZE];
if (gwbuf_copy_data(buffer, MYSQL_PS_PARAMS_OFFSET, sizeof(params), params) == sizeof(params))
{
rval = gw_mysql_get_byte2(params);
}
return rval;
}
bool have_semicolon(const char* ptr, int len)
{
for (int i = 0; i < len; i++)
@ -265,7 +278,7 @@ public:
break;
case MXS_COM_STMT_PREPARE:
m_binary_ps[id] = get_prepare_type(buffer);
m_binary_ps[id].type = get_prepare_type(buffer);
break;
default:
@ -281,7 +294,7 @@ public:
if (it != m_binary_ps.end())
{
rval = it->second;
rval = it->second.type;
}
else
{
@ -342,8 +355,32 @@ public:
}
}
void set_param_count(uint32_t id, uint16_t param_count)
{
m_binary_ps[id].param_count = param_count;
}
uint16_t param_count(uint32_t id) const
{
uint16_t rval = 0;
auto it = m_binary_ps.find(id);
if (it != m_binary_ps.end())
{
rval = it->second.param_count;
}
return rval;
}
private:
typedef std::unordered_map<uint32_t, uint32_t> BinaryPSMap;
struct BinaryPS
{
uint32_t type = 0;
uint16_t param_count = 0;
};
typedef std::unordered_map<uint32_t, BinaryPS> BinaryPSMap;
typedef std::unordered_map<std::string, uint32_t> TextPSMap;
private:
@ -368,6 +405,7 @@ QueryClassifier::QueryClassifier(Handler* pHandler,
, m_multi_statements_allowed(are_multi_statements_allowed(pSession))
, m_sPs_manager(new PSManager)
, m_trx_is_read_only(true)
, m_ps_continuation(false)
{
}
@ -622,9 +660,15 @@ uint32_t QueryClassifier::ps_id_internal_get(GWBUF* pBuffer)
return internal_id;
}
void QueryClassifier::ps_id_internal_put(uint32_t external_id, uint32_t internal_id)
void QueryClassifier::ps_store_response(uint32_t internal_id, GWBUF* buffer)
{
auto external_id = qc_mysql_extract_ps_id(buffer);
m_ps_handles[external_id] = internal_id;
if (auto param_count = qc_extract_ps_param_count(buffer))
{
m_sPs_manager->set_param_count(internal_id, param_count);
}
}
void QueryClassifier::log_transaction_status(GWBUF* querybuf, uint32_t qtype)
@ -909,6 +953,38 @@ QueryClassifier::current_target_t QueryClassifier::handle_multi_temp_and_load(
return rv;
}
bool QueryClassifier::query_continues_ps(uint8_t cmd, uint32_t stmt_id, GWBUF* buffer)
{
bool rval = false;
if (cmd == COM_STMT_FETCH)
{
// COM_STMT_FETCH should always go to the same target as the COM_STMT_EXECUTE
rval = true;
}
else if (cmd == MXS_COM_STMT_EXECUTE)
{
if (auto params = m_sPs_manager->param_count(stmt_id))
{
size_t types_offset = MYSQL_HEADER_LEN + 1 + 4 + 1 + 4 + ((params + 7) / 8);
uint8_t have_types = 0;
if (gwbuf_copy_data(buffer, types_offset, 1, &have_types))
{
if (have_types == 0)
{
// A previous COM_STMT_EXECUTE provided the field types, and this one relies on the
// previous one. This means that this query must be routed to the same server where the
// previous COM_STMT_EXECUTE was routed.
rval = true;
}
}
}
}
return rval;
}
QueryClassifier::RouteInfo QueryClassifier::update_route_info(
QueryClassifier::current_target_t current_target,
GWBUF* pBuffer)
@ -1005,6 +1081,7 @@ QueryClassifier::RouteInfo QueryClassifier::update_route_info(
{
stmt_id = ps_id_internal_get(pBuffer);
type_mask = ps_get_type(stmt_id);
m_ps_continuation = query_continues_ps(command, stmt_id, pBuffer);
}
route_target = get_route_target(command, type_mask);