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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
4 changed files with 43 additions and 24 deletions
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45
server/core/modutil.cc
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@ -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;