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MXS-1776: Handle recursive COM_STMT_EXECUTE commands

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Readwritesplit would not handle multiple overlapping COM_STMT_EXECUTE
commands properly if they opened cursors. This was due to the fact that
the result would not be marked as complete and COM_STMT_FETCH commands
were executed as if they did not return results.

The correct implementation is to consider a COM_STMT_EXECUTE that opens a
cursor complete only when the first EOF packet is read (that is, when the
resultset header is read). This allows subsequent COM_STMT_FETCH commands
to be handled separately.

The separate COM_STMT_FETCH handling must count the number of packets that
are being fetched. This allows correct tracking of the state of a
COM_STMT_FETCH by checking that the number of packets is correct or the
second EOF/ERR packet is read.
This commit is contained in:
Markus Mäkelä
2018-04-11 15:16:22 +03:00
parent 252475cdc5
commit 311adf817f
6 changed files with 79 additions and 5 deletions
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23
server/modules/routing/readwritesplit/readwritesplit.cc
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@ -520,7 +520,20 @@ static inline bool have_next_packet(GWBUF* buffer)
*/
bool reply_is_complete(SRWBackend& backend, GWBUF *buffer)
{
if (backend->get_reply_state() == REPLY_STATE_START &&
if (backend->current_command() == MXS_COM_STMT_FETCH)
{
bool more = false;
modutil_state state = {backend->is_large_packet()};
int n_eof = modutil_count_signal_packets(buffer, 0, &more, &state);
backend->set_large_packet(state.state);
if (n_eof > 0 || backend->consume_fetched_rows(buffer))
{
LOG_RS(backend, REPLY_STATE_DONE);
backend->set_reply_state(REPLY_STATE_DONE);
}
}
else if (backend->get_reply_state() == REPLY_STATE_START &&
(!mxs_mysql_is_result_set(buffer) || GWBUF_IS_COLLECTED_RESULT(buffer)))
{
if (GWBUF_IS_COLLECTED_RESULT(buffer) ||
@ -575,6 +588,13 @@ bool reply_is_complete(SRWBackend& backend, GWBUF *buffer)
/** Waiting for the EOF packet after the rows */
LOG_RS(backend, REPLY_STATE_RSET_ROWS);
backend->set_reply_state(REPLY_STATE_RSET_ROWS);
if (backend->cursor_is_open())
{
MXS_INFO("Cursor successfully opened");
LOG_RS(backend, REPLY_STATE_DONE);
backend->set_reply_state(REPLY_STATE_DONE);
}
}
else
{
@ -927,7 +947,6 @@ static int routeQuery(MXS_ROUTER *instance, MXS_ROUTER_SESSION *router_session,
{
if (rses->query_queue == NULL &&
(rses->expected_responses == 0 ||
mxs_mysql_get_command(querybuf) == MXS_COM_STMT_FETCH ||
rses->load_data_state == LOAD_DATA_ACTIVE ||
rses->large_query))
{