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Cache the local server statistics object

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By storing the server statistics object in side the session, the lookup
involved in getting a worker-local value is avoided. Since the lookup is
done multiple times for a single query, it is beneficial to store it in
the session.

As the worker-local value is never deleted, it is safe to store a
reference to it in the session. It is also never updated concurrently so
no atomic operations are necessary.
This commit is contained in:
Markus Mäkelä
2018-12-09 15:01:52 +02:00
parent 1fa3b133c7
commit 9adbd2f8f0
6 changed files with 19 additions and 14 deletions
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4
include/maxscale/session_stats.hh
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@ -15,7 +15,7 @@
#include <maxscale/ccdefs.hh> #include <maxscale/ccdefs.hh>
#include <map> #include <unordered_map>
#include <maxscale/server.h> #include <maxscale/server.h>
#include <maxbase/average.hh> #include <maxbase/average.hh>
@ -59,5 +59,5 @@ private:
maxbase::CumulativeAverage m_num_ave_session_selects; maxbase::CumulativeAverage m_num_ave_session_selects;
}; };
using SrvStatMap = std::map<SERVER*, ServerStats>; using SrvStatMap = std::unordered_map<SERVER*, ServerStats>;
} }

4
server/modules/routing/readwritesplit/readwritesplit.cc
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@ -107,9 +107,9 @@ const Stats& RWSplit::stats() const
return m_stats; return m_stats;
} }
ServerStats& RWSplit::server_stats(SERVER* server) SrvStatMap& RWSplit::local_server_stats()
{ {
return (*m_server_stats)[server]; return *m_server_stats;
} }
maxscale::SrvStatMap RWSplit::all_server_stats() const maxscale::SrvStatMap RWSplit::all_server_stats() const

2
server/modules/routing/readwritesplit/readwritesplit.hh
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@ -264,7 +264,7 @@ public:
const Config& config() const; const Config& config() const;
Stats& stats(); Stats& stats();
const Stats& stats() const; const Stats& stats() const;
ServerStats& server_stats(SERVER* server); SrvStatMap& local_server_stats();
SrvStatMap all_server_stats() const; SrvStatMap all_server_stats() const;
int max_slave_count() const; int max_slave_count() const;

10
server/modules/routing/readwritesplit/rwsplit_route_stmt.cc
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@ -477,8 +477,8 @@ bool RWSplitSession::route_session_write(GWBUF* querybuf, uint8_t command, uint3
{ {
nsucc += 1; nsucc += 1;
mxb::atomic::add(&backend->server()->stats.packets, 1, mxb::atomic::RELAXED); mxb::atomic::add(&backend->server()->stats.packets, 1, mxb::atomic::RELAXED);
m_router->server_stats(backend->server()).total++; m_server_stats[backend->server()].total++;
m_router->server_stats(backend->server()).read++; m_server_stats[backend->server()].read++;
if (expecting_response) if (expecting_response)
{ {
@ -853,7 +853,7 @@ SRWBackend RWSplitSession::handle_slave_is_target(uint8_t cmd, uint32_t stmt_id)
if (target) if (target)
{ {
mxb::atomic::add(&m_router->stats().n_slave, 1, mxb::atomic::RELAXED); mxb::atomic::add(&m_router->stats().n_slave, 1, mxb::atomic::RELAXED);
m_router->server_stats(target->server()).read++; m_server_stats[target->server()].read++;
mxb_assert(target->in_use() || target->can_connect()); mxb_assert(target->in_use() || target->can_connect());
} }
else else
@ -990,7 +990,7 @@ bool RWSplitSession::handle_master_is_target(SRWBackend* dest)
if (target && target == m_current_master) if (target && target == m_current_master)
{ {
mxb::atomic::add(&m_router->stats().n_master, 1, mxb::atomic::RELAXED); mxb::atomic::add(&m_router->stats().n_master, 1, mxb::atomic::RELAXED);
m_router->server_stats(target->server()).write++; m_server_stats[target->server()].write++;
} }
else else
{ {
@ -1170,7 +1170,7 @@ bool RWSplitSession::handle_got_target(GWBUF* querybuf, SRWBackend& target, bool
mxb::atomic::add(&m_router->stats().n_queries, 1, mxb::atomic::RELAXED); mxb::atomic::add(&m_router->stats().n_queries, 1, mxb::atomic::RELAXED);
mxb::atomic::add(&target->server()->stats.packets, 1, mxb::atomic::RELAXED); mxb::atomic::add(&target->server()->stats.packets, 1, mxb::atomic::RELAXED);
m_router->server_stats(target->server()).total++; m_server_stats[target->server()].total++;
if (!m_qc.large_query() && response == mxs::Backend::EXPECT_RESPONSE) if (!m_qc.large_query() && response == mxs::Backend::EXPECT_RESPONSE)
{ {

9
server/modules/routing/readwritesplit/rwsplitsession.cc
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@ -45,6 +45,7 @@ RWSplitSession::RWSplitSession(RWSplit* instance,
, m_retry_duration(0) , m_retry_duration(0)
, m_is_replay_active(false) , m_is_replay_active(false)
, m_can_replay_trx(true) , m_can_replay_trx(true)
, m_server_stats(instance->local_server_stats())
{ {
if (m_config.rw_max_slave_conn_percent) if (m_config.rw_max_slave_conn_percent)
{ {
@ -84,7 +85,7 @@ RWSplitSession* RWSplitSession::create(RWSplit* router, MXS_SESSION* session)
for (auto& b : backends) for (auto& b : backends)
{ {
router->server_stats(b->server()).start_session(); rses->m_server_stats[b->server()].start_session();
} }
} }
} }
@ -122,9 +123,9 @@ void RWSplitSession::close()
} }
backend->response_stat().reset(); backend->response_stat().reset();
m_router->server_stats(backend->server()).end_session(backend->session_timer().split(), m_server_stats[backend->server()].end_session(backend->session_timer().split(),
backend->select_timer().total(), backend->select_timer().total(),
backend->num_selects()); backend->num_selects());
} }
} }

4
server/modules/routing/readwritesplit/rwsplitsession.hh
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@ -169,6 +169,10 @@ public:
otrx_state m_otrx_state = OTRX_INACTIVE; /**< Optimistic trx state*/ otrx_state m_otrx_state = OTRX_INACTIVE; /**< Optimistic trx state*/
SrvStatMap& m_server_stats; /**< The server stats local to this thread, cached in the session object.
* This avoids the lookup involved in getting the worker-local value from
* the worker's container.*/
private: private:
RWSplitSession(RWSplit* instance, RWSplitSession(RWSplit* instance,
MXS_SESSION* session, MXS_SESSION* session,