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Refactor Backend class states

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The states are now internal to the Backend class. This simplifies the use
of the class by moving the burder of state tracking to the class
itself.

Refactored the way the schemarouter uses the Backend class.

Also fixed a memory leak in the schemarouter when `ignore_databases_regex`
was used..
This commit is contained in:
Markus Mäkelä
2017-06-13 22:36:08 +03:00
parent bbfd9ce136
commit 18993bc8ca
3 changed files with 137 additions and 102 deletions
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95
server/core/backend.cc
View File

@ -21,7 +21,6 @@ Backend::Backend(SERVER_REF *ref):
m_closed(false),
m_backend(ref),
m_dcb(NULL),
m_num_result_wait(0),
m_state(0)
{
}
@ -36,7 +35,7 @@ Backend::~Backend()
}
}
void Backend::close()
void Backend::close(close_type type)
{
if (!m_closed)
{
@ -47,12 +46,17 @@ void Backend::close()
CHK_DCB(m_dcb);
/** Clean operation counter in bref and in SERVER */
while (is_waiting_result())
if (is_waiting_result())
{
clear_state(BREF_WAITING_RESULT);
clear_state(WAITING_RESULT);
}
clear_state(IN_USE);
set_state(CLOSED);
if (type == FATAL)
{
set_state(FATAL_FAILURE);
}
clear_state(BREF_IN_USE);
set_state(BREF_CLOSED);
dcb_close(m_dcb);
@ -75,18 +79,22 @@ bool Backend::execute_session_command()
CHK_DCB(m_dcb);
int rc = 0;
SessionCommandList::iterator iter = m_session_commands.begin();
SessionCommand& sescmd = *(*iter);
GWBUF *buffer = sescmd.copy_buffer().release();
bool rval = false;
switch (sescmd.get_command())
{
case MYSQL_COM_QUIT:
case MYSQL_COM_STMT_CLOSE:
rval = write(buffer, NO_RESPONSE);
break;
case MYSQL_COM_CHANGE_USER:
/** This makes it possible to handle replies correctly */
gwbuf_set_type(buffer, GWBUF_TYPE_SESCMD);
rc = m_dcb->func.auth(m_dcb, NULL, m_dcb->session, buffer);
rval = auth(buffer);
break;
case MYSQL_COM_QUERY:
@ -96,11 +104,11 @@ bool Backend::execute_session_command()
* MySQL command to protocol
*/
gwbuf_set_type(buffer, GWBUF_TYPE_SESCMD);
rc = m_dcb->func.write(m_dcb, buffer);
rval = write(buffer);
break;
}
return rc == 1;
return rval;
}
void Backend::add_session_command(GWBUF* buffer, uint64_t sequence)
@ -120,32 +128,26 @@ size_t Backend::session_command_count() const
return m_session_commands.size();
}
void Backend::clear_state(enum bref_state state)
void Backend::clear_state(backend_state state)
{
if (state != BREF_WAITING_RESULT)
if ((state & WAITING_RESULT) && (m_state & WAITING_RESULT))
{
m_state &= ~state;
}
else
{
/** Decrease global operation count */
ss_debug(int prev2 = )atomic_add(&m_backend->server->stats.n_current_ops, -1);
ss_dassert(prev2 > 0);
}
m_state &= ~state;
}
void Backend::set_state(enum bref_state state)
void Backend::set_state(backend_state state)
{
if (state != BREF_WAITING_RESULT)
if ((state & WAITING_RESULT) && (m_state & WAITING_RESULT) == 0)
{
m_state |= state;
}
else
{
/** Increase global operation count */
ss_debug(int prev2 = )atomic_add(&m_backend->server->stats.n_current_ops, 1);
ss_dassert(prev2 >= 0);
}
m_state |= state;
}
SERVER_REF* Backend::backend() const
@ -159,7 +161,7 @@ bool Backend::connect(MXS_SESSION* session)
if ((m_dcb = dcb_connect(m_backend->server, session, m_backend->server->protocol)))
{
m_state = BREF_IN_USE;
m_state = IN_USE;
atomic_add(&m_backend->connections, 1);
rval = true;
}
@ -172,9 +174,35 @@ DCB* Backend::dcb() const
return m_dcb;
}
bool Backend::write(GWBUF* buffer)
bool Backend::write(GWBUF* buffer, response_type type)
{
return m_dcb->func.write(m_dcb, buffer) != 0;
bool rval = m_dcb->func.write(m_dcb, buffer) != 0;
if (rval && type == EXPECT_RESPONSE)
{
set_state(WAITING_RESULT);
}
return rval;
}
bool Backend::auth(GWBUF* buffer)
{
bool rval = false;
if (m_dcb->func.auth(m_dcb, NULL, m_dcb->session, buffer) == 1)
{
set_state(WAITING_RESULT);
rval = true;
}
return rval;
}
void Backend::ack_write()
{
ss_dassert(is_waiting_result());
clear_state(WAITING_RESULT);
}
void Backend::store_command(GWBUF* buffer)
@ -201,20 +229,15 @@ bool Backend::write_stored_command()
bool Backend::in_use() const
{
return m_state & BREF_IN_USE;
return m_state & IN_USE;
}
bool Backend::is_waiting_result() const
{
return m_num_result_wait > 0;
}
bool Backend::is_query_active() const
{
return m_state & BREF_QUERY_ACTIVE;
return m_state & WAITING_RESULT;
}
bool Backend::is_closed() const
{
return m_state & BREF_CLOSED;
return m_state & CLOSED;
}

46
server/modules/routing/schemarouter/schemaroutersession.cc
View File

@ -97,9 +97,13 @@ void SchemaRouterSession::close()
for (SSRBackendList::iterator it = m_backends.begin(); it != m_backends.end(); it++)
{
SSRBackend& bref = *it;
/** The backends are closed here to trigger the shutdown of
* the connected DCBs */
(*it)->close();
if (bref->in_use())
{
bref->close();
}
}
spinlock_acquire(&m_router->m_lock);
@ -434,20 +438,19 @@ int32_t SchemaRouterSession::routeQuery(GWBUF* pPacket)
pPacket = NULL;
ret = 1;
}
else if ((ret = target_dcb->func.write(target_dcb, gwbuf_clone(pPacket))) == 1)
else if (bref->write(pPacket))
{
/** Add one query response waiter to backend reference */
bref->set_state(BREF_QUERY_ACTIVE);
bref->set_state(BREF_WAITING_RESULT);
atomic_add(&m_router->m_stats.n_queries, 1);
ret = 1;
}
else
{
MXS_ERROR("Routing query failed.");
gwbuf_free(pPacket);
}
}
gwbuf_free(pPacket);
return ret;
}
void SchemaRouterSession::handle_mapping_reply(SSRBackend& bref, GWBUF** pPacket)
@ -506,17 +509,6 @@ void SchemaRouterSession::process_sescmd_response(SSRBackend& bref, GWBUF** ppPa
*ppPacket = NULL;
}
}
if (*ppPacket)
{
bref->clear_state(BREF_WAITING_RESULT);
}
}
else if (bref->is_query_active())
{
bref->clear_state(BREF_QUERY_ACTIVE);
/** Set response status as replied */
bref->clear_state(BREF_WAITING_RESULT);
}
}
@ -565,6 +557,10 @@ void SchemaRouterSession::clientReply(GWBUF* pPacket, DCB* pDcb)
{
process_sescmd_response(bref, &pPacket);
ss_dassert(bref->is_waiting_result());
/** Set response status as replied */
bref->ack_write();
if (pPacket)
{
MXS_SESSION_ROUTE_REPLY(pDcb->session, pPacket);
@ -579,8 +575,6 @@ void SchemaRouterSession::clientReply(GWBUF* pPacket, DCB* pDcb)
else if (bref->write_stored_command())
{
atomic_add(&m_router->m_stats.n_queries, 1);
bref->set_state(BREF_QUERY_ACTIVE);
bref->set_state(BREF_WAITING_RESULT);
}
}
@ -744,19 +738,6 @@ bool SchemaRouterSession::route_session_write(GWBUF* querybuf, uint8_t command)
if ((*it)->session_command_count() == 1)
{
/** Only one command, execute it */
switch (command)
{
/** These types of commands don't generate responses */
case MYSQL_COM_QUIT:
case MYSQL_COM_STMT_CLOSE:
break;
default:
(*it)->set_state(BREF_WAITING_RESULT);
break;
}
if ((*it)->execute_session_command())
{
succp = true;
@ -781,6 +762,7 @@ bool SchemaRouterSession::route_session_write(GWBUF* querybuf, uint8_t command)
}
}
gwbuf_free(querybuf);
return succp;
}
@ -1246,6 +1228,8 @@ bool SchemaRouterSession::ignore_duplicate_database(const char* data)
{
rval = true;
}
pcre2_match_data_free(match_data);
}
return rval;