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Remove unnecessary result processing in readwritesplit

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The result processing code did unnecessary work to confirm that the result
buffers are contiguous. The code also assumed that multiple packets can be
routed at the same time when in fact only one contiguous result packet is
returned at a time.

By assuming that the buffers are contiguous and contain only one packet,
most of the copying and buffer manipulation can be avoided.
This commit is contained in:
Markus Mäkelä
2017-10-05 16:03:00 +03:00
parent 6ba20795b4
commit e474b78d95
3 changed files with 49 additions and 16 deletions
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45
server/modules/routing/readwritesplit/readwritesplit.cc
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@ -508,6 +508,25 @@ static bool route_stored_query(RWSplitSession *rses)
return rval;
}
static bool is_eof(GWBUF* buffer)
{
uint8_t* data = GWBUF_DATA(buffer);
return data[MYSQL_HEADER_LEN] == MYSQL_REPLY_EOF &&
gw_mysql_get_byte3(data) + MYSQL_HEADER_LEN == MYSQL_EOF_PACKET_LEN;
}
static bool is_large(GWBUF* buffer)
{
return gw_mysql_get_byte3(GWBUF_DATA(buffer)) == GW_MYSQL_MAX_PACKET_LEN;
}
static bool more_results_exist(GWBUF* buffer)
{
ss_dassert(is_eof(buffer));
uint16_t status = gw_mysql_get_byte2(GWBUF_DATA(buffer) + MYSQL_HEADER_LEN + 1 + 2);
return status & SERVER_MORE_RESULTS_EXIST;
}
/**
* @brief Check if we have received a complete reply from the backend
*
@ -531,11 +550,23 @@ bool reply_is_complete(SRWBackend backend, GWBUF *buffer)
}
else
{
bool more = false;
modutil_state state = backend->get_modutil_state();
int old_eof = backend->get_reply_state() == REPLY_STATE_RSET_ROWS ? 1 : 0;
int n_eof = modutil_count_signal_packets(buffer, old_eof, &more, &state);
backend->set_modutil_state(state);
bool large = backend->is_large_packet();
int n_eof = backend->get_reply_state() == REPLY_STATE_RSET_ROWS ? 1 : 0;
if (is_large(buffer))
{
large = true;
}
else if (large)
{
large = false;
}
else if (is_eof(buffer))
{
n_eof++;
}
backend->set_large_packet(large);
if (n_eof == 0)
{
@ -557,7 +588,7 @@ bool reply_is_complete(SRWBackend backend, GWBUF *buffer)
LOG_RS(backend, REPLY_STATE_DONE);
backend->set_reply_state(REPLY_STATE_DONE);
if (more)
if (more_results_exist(buffer))
{
/** The server will send more resultsets */
LOG_RS(backend, REPLY_STATE_START);
@ -1116,6 +1147,8 @@ static void clientReply(MXS_ROUTER *instance,
GWBUF *writebuf,
DCB *backend_dcb)
{
ss_dassert(GWBUF_IS_CONTIGUOUS(writebuf) &&
MYSQL_GET_PAYLOAD_LEN(GWBUF_DATA(writebuf)) + MYSQL_HEADER_LEN == gwbuf_length(writebuf));
RWSplitSession *rses = (RWSplitSession *)router_session;
DCB *client_dcb = backend_dcb->session->client_dcb;