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MXS-1203: Improve resultset processing functions

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The functions used to track the resultset EOF packets now expose the
position of the end of the result set. This allows the modules that use
them to check if more results exist in the same buffer.

Added the status bits for OK and EOF packets to the mysql.h protocol
header. This can be used to check for various state changes that happen in
the session. Currently the status bits are only used to detect if more
results are expected.
This commit is contained in:
Markus Mäkelä
2017-04-03 14:40:06 +03:00
parent a1c7ee438d
commit d7258fffd0
5 changed files with 131 additions and 75 deletions
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92
server/core/modutil.cc
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@ -633,83 +633,45 @@ GWBUF* modutil_get_complete_packets(GWBUF **p_readbuf)
return complete;
}
/**
* Count the number of EOF, OK or ERR packets in the buffer. Only complete
* packets are inspected and the buffer is assumed to only contain whole packets.
* If partial packets are in the buffer, they are ignored. The caller must handle the
* detection of partial packets in buffers.
* @param reply Buffer to use
* @param use_ok Whether the DEPRECATE_EOF flag is set
* @param n_found If there were previous packets found
* @return Number of EOF packets
*/
int
modutil_count_signal_packets(GWBUF *reply, int use_ok, int n_found, int* more)
int modutil_count_signal_packets(GWBUF *reply, int n_found, bool* more, size_t* offset)
{
unsigned char* ptr = (unsigned char*) reply->start;
unsigned char* end = (unsigned char*) reply->end;
unsigned char* prev = ptr;
int pktlen, eof = 0, err = 0;
int errlen = 0, eoflen = 0;
int iserr = 0, iseof = 0;
bool moreresults = false;
while (ptr < end)
{
pktlen = MYSQL_GET_PAYLOAD_LEN(ptr) + 4;
unsigned int len = gwbuf_length(reply);
int eof = 0;
int err = 0;
if ((iserr = PTR_IS_ERR(ptr)) || (iseof = PTR_IS_EOF(ptr)))
while (*offset < len)
{
uint8_t header[MYSQL_HEADER_LEN + 5]; // Maximum size of an EOF packet
gwbuf_copy_data(reply, *offset, MYSQL_HEADER_LEN + 1, header);
unsigned int pktlen = MYSQL_GET_PAYLOAD_LEN(header) + MYSQL_HEADER_LEN;
if (MYSQL_GET_COMMAND(header) == MYSQL_REPLY_ERR)
{
if (iserr)
{
err++;
errlen = pktlen;
}
else if (iseof)
{
eof++;
eoflen = pktlen;
}
err++;
}
else if (MYSQL_GET_COMMAND(header) == MYSQL_REPLY_EOF &&
pktlen == 5 + MYSQL_HEADER_LEN)
{
eof++;
}
if ((ptr + pktlen) > end || (eof + n_found) >= 2)
if (*offset + pktlen >= len || (eof + err + n_found) >= 2)
{
moreresults = PTR_EOF_MORE_RESULTS(ptr);
ptr = prev;
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) & MXS_MYSQL_MORE_RESULTS_EXISTS);
*offset += pktlen;
break;
}
prev = ptr;
ptr += pktlen;
*offset += pktlen;
}
int total = err + eof + n_found;
/*
* If there were new EOF/ERR packets found, make sure that they are the last
* packet in the buffer.
*/
if ((eof || err) && n_found)
{
if (err)
{
ptr -= errlen;
if (!PTR_IS_ERR(ptr))
{
err = 0;
}
}
else
{
ptr -= eoflen;
if (!PTR_IS_EOF(ptr))
{
eof = 0;
}
}
}
*more = moreresults;
return (eof + err);
return total;
}
/**