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MXS-1778: Add support for MariaDB GTID tracking

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The MariaDB implementation allows the last GTID to be tracked with the
`last_gtid` variable. To do this, the configuration option
`session_track_system_variables=last_gtid` must be used or it must be
enabled at runtime.
This commit is contained in:
Markus Mäkelä
2018-05-20 22:35:03 +03:00
parent 6d1c0e5ba6
commit 4ba0ac434b
5 changed files with 41 additions and 16 deletions
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36
server/modules/routing/readwritesplit/rwsplitsession.cc
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@ -36,7 +36,7 @@ RWSplitSession::RWSplitSession(RWSplit* instance, MXS_SESSION* session,
m_sent_sescmd(0),
m_recv_sescmd(0),
m_gtid_pos(""),
m_waiting_for_gtid(false),
m_wait_gtid(NONE),
m_next_seq(0),
m_qc(this, session, instance->config().use_sql_variables_in),
m_retry_duration(0),
@ -245,19 +245,24 @@ bool RWSplitSession::route_stored_query()
*/
GWBUF* RWSplitSession::discard_master_wait_gtid_result(GWBUF *buffer)
{
// MASTER_WAIT_GTID is complete, discard the OK packet or return the ERR packet
m_waiting_for_gtid = false;
uint8_t header_and_command[MYSQL_HEADER_LEN + 1];
gwbuf_copy_data(buffer, 0, MYSQL_HEADER_LEN + 1, header_and_command);
if (MYSQL_GET_COMMAND(header_and_command) == MYSQL_REPLY_OK)
{
// MASTER_WAIT_GTID is complete, discard the OK packet or return the ERR packet
m_wait_gtid = UPDATING_PACKETS;
// Discard the OK packet and start updating sequence numbers
uint8_t packet_len = MYSQL_GET_PAYLOAD_LEN(header_and_command) + MYSQL_HEADER_LEN;
m_next_seq = 1;
buffer = gwbuf_consume(buffer, packet_len);
}
else if (MYSQL_GET_COMMAND(header_and_command) == MYSQL_REPLY_ERR)
{
// The MASTER_WAIT_GTID command failed and no further packets will come
m_wait_gtid = NONE;
}
return buffer;
}
@ -356,19 +361,19 @@ GWBUF* RWSplitSession::handle_causal_read_reply(GWBUF *writebuf, SRWBackend& bac
if (GWBUF_IS_REPLY_OK(writebuf) && backend == m_current_master)
{
/** Save gtid position */
char *tmp = gwbuf_get_property(writebuf, (char *)"gtid");
char *tmp = gwbuf_get_property(writebuf, MXS_LAST_GTID);
if (tmp)
{
m_gtid_pos = std::string(tmp);
}
}
if (m_waiting_for_gtid)
if (m_wait_gtid == WAITING_FOR_HEADER)
{
writebuf = discard_master_wait_gtid_result(writebuf);
}
if (writebuf)
if (m_wait_gtid == UPDATING_PACKETS && writebuf)
{
correct_packet_sequence(writebuf);
}
@ -420,11 +425,6 @@ void RWSplitSession::clientReply(GWBUF *writebuf, DCB *backend_dcb)
SRWBackend& backend = get_backend_from_dcb(backend_dcb);
if ((writebuf = handle_causal_read_reply(writebuf, backend)) == NULL)
{
return; // Nothing to route, return
}
if (backend->get_reply_state() == REPLY_STATE_DONE)
{
/** If we receive an unexpected response from the server, the internal
@ -435,6 +435,11 @@ void RWSplitSession::clientReply(GWBUF *writebuf, DCB *backend_dcb)
return;
}
if ((writebuf = handle_causal_read_reply(writebuf, backend)) == NULL)
{
return; // Nothing to route, return
}
if (m_config.transaction_replay && m_can_replay_trx &&
session_trx_is_active(m_client->session))
{
@ -469,6 +474,13 @@ void RWSplitSession::clientReply(GWBUF *writebuf, DCB *backend_dcb)
ss_dassert(backend->get_reply_state() == REPLY_STATE_DONE);
MXS_INFO("Reply complete, last reply from %s", backend->name());
if (m_config.enable_causal_read)
{
// The reply should never be complete while we are still waiting for the header.
ss_dassert(m_wait_gtid != WAITING_FOR_HEADER);
m_wait_gtid = NONE;
}
if (backend->local_infile_requested())
{
// Server requested a local file, go into data streaming mode