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MXS-1825: Fix PS output parameter tracking for MySQL variants

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The resultset processing for MySQL requires some extra work as it lacks
the proper SERVER_MORE_RESULTS_EXIST flag in the last EOF packet. Instead,
the first EOF packet has the SERVER_PS_OUT_PARAMS flag which needs to be
interpreted as a SERVER_MORE_RESULTS_EXIST flag for the second EOF packet.

Also corrected the EOF packet handling to do the flag checks in the code
that deals with the EOF packets.

As the modutil_state parameter is now used for more than large packet
tracking, the correct solution is to store this state object in the
readwritesplit session instead of interpreting it to a boolean value.
This commit is contained in:
Markus Mäkelä 2018-04-26 09:22:17 +03:00
parent 260fcf85ec
commit c97d2c94eb
No known key found for this signature in database
GPG Key ID: 72D48FCE664F7B19
4 changed files with 43 additions and 24 deletions
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45
server/core/modutil.cc
View File

@ -630,14 +630,20 @@ GWBUF* modutil_get_complete_packets(GWBUF **p_readbuf)
int modutil_count_signal_packets(GWBUF *reply, int n_found, bool* more_out, modutil_state* state)
{
enum
{
SKIP_NEXT = 0x1,
PS_OUT_PARAM = 0x2,
};
unsigned int len = gwbuf_length(reply);
int eof = 0;
int err = 0;
size_t offset = 0;
bool skip_next = state ? state->state : false;
bool more = false;
bool only_ok = true;
uint64_t num_packets = 0;
uint8_t internal_state = state ? state->state : 0;
while (offset < len)
{
@ -652,12 +658,12 @@ int modutil_count_signal_packets(GWBUF *reply, int n_found, bool* more_out, modu
if (payloadlen == GW_MYSQL_MAX_PACKET_LEN)
{
only_ok = false;
skip_next = true;
internal_state |= SKIP_NEXT;
}
else if (skip_next)
else if (internal_state & SKIP_NEXT)
{
only_ok = false;
skip_next = false;
internal_state &= ~SKIP_NEXT;
}
else
{
@ -675,6 +681,28 @@ int modutil_count_signal_packets(GWBUF *reply, int n_found, bool* more_out, modu
{
eof++;
only_ok = false;
uint8_t status[2]; // Two byte server status
gwbuf_copy_data(reply, offset + MYSQL_HEADER_LEN + 1 + 2, sizeof(status), status);
more = gw_mysql_get_byte2(status) & SERVER_MORE_RESULTS_EXIST;
/**
* MySQL 5.6 and 5.7 have a "feature" that doesn't set
* the SERVER_MORE_RESULTS_EXIST flag in the last EOF packet of
* a result set if the SERVER_PS_OUT_PARAMS flag was set in
* the first result set. To handle this, we have to store
* the information from the first EOF packet until we process
* the second EOF packet.
*/
if (gw_mysql_get_byte2(status) & SERVER_PS_OUT_PARAMS)
{
internal_state |= PS_OUT_PARAM;
}
else if (internal_state & PS_OUT_PARAM)
{
more = true;
internal_state &= ~PS_OUT_PARAM;
}
}
else if (command == MYSQL_REPLY_OK && pktlen >= MYSQL_OK_PACKET_MIN_LEN &&
(eof + n_found) % 2 == 0)
@ -696,13 +724,6 @@ int modutil_count_signal_packets(GWBUF *reply, int n_found, bool* more_out, modu
}
}
if (offset + pktlen >= len || (eof + err + n_found) >= 2)
{
gwbuf_copy_data(reply, offset, sizeof(header), header);
uint16_t* status = (uint16_t*)(header + MYSQL_HEADER_LEN + 1 + 2); // Skip command and warning count
more = ((*status) & SERVER_MORE_RESULTS_EXIST);
}
offset += pktlen;
if (offset >= GWBUF_LENGTH(reply) && reply->next)
@ -717,7 +738,7 @@ int modutil_count_signal_packets(GWBUF *reply, int n_found, bool* more_out, modu
if (state)
{
state->state = skip_next;
state->state = internal_state;
}
*more_out = more;

8
server/modules/routing/readwritesplit/readwritesplit.cc
View File

@ -523,9 +523,9 @@ bool reply_is_complete(SRWBackend& backend, GWBUF *buffer)
if (backend->current_command() == MXS_COM_STMT_FETCH)
{
bool more = false;
modutil_state state = {backend->is_large_packet()};
modutil_state state = backend->get_modutil_state();
int n_eof = modutil_count_signal_packets(buffer, 0, &more, &state);
backend->set_large_packet(state.state);
backend->set_modutil_state(state);
// If the server responded with an error, n_eof > 0
if (n_eof > 0 || backend->consume_fetched_rows(buffer))
@ -569,10 +569,10 @@ bool reply_is_complete(SRWBackend& backend, GWBUF *buffer)
else
{
bool more = false;
modutil_state state = {backend->is_large_packet()};
modutil_state state = backend->get_modutil_state();
int n_old_eof = backend->get_reply_state() == REPLY_STATE_RSET_ROWS ? 1 : 0;
int n_eof = modutil_count_signal_packets(buffer, n_old_eof, &more, &state);
backend->set_large_packet(state.state);
backend->set_modutil_state(state);
if (n_eof > 2)
{

2
server/modules/routing/readwritesplit/rwsplitsession.cc
View File

@ -17,7 +17,7 @@
RWBackend::RWBackend(SERVER_REF* ref):
mxs::Backend(ref),
m_reply_state(REPLY_STATE_DONE),
m_large_packet(false),
m_modutil_state({}),
m_command(0),
m_opening_cursor(false),
m_expected_rows(0)

12
server/modules/routing/readwritesplit/rwsplitsession.hh
View File

@ -62,14 +62,14 @@ public:
// For COM_STMT_FETCH processing
bool consume_fetched_rows(GWBUF* buffer);
inline void set_large_packet(bool value)
inline void set_modutil_state(modutil_state value)
{
m_large_packet = value;
m_modutil_state = value;
}
inline bool is_large_packet() const
inline modutil_state get_modutil_state() const
{
return m_large_packet;
return m_modutil_state;
}
inline uint8_t current_command() const
@ -90,9 +90,7 @@ public:
private:
reply_state_t m_reply_state;
BackendHandleMap m_ps_handles; /**< Internal ID to backend PS handle mapping */
bool m_large_packet; /**< Used to store the state of the EOF packet
*calculation for result sets when the result
* contains very large rows */
modutil_state m_modutil_state; /**< @see modutil_count_signal_packets */
uint8_t m_command;
bool m_opening_cursor; /**< Whether we are opening a cursor */
uint32_t m_expected_rows; /**< Number of rows a COM_STMT_FETCH is retrieving */