Log_thread_waiting Struct Reference

Small utility which is used inside log threads when they have to wait for next interesting event to happen. More...

Public Member Functions
	Log_thread_waiting (const log_t &log, os_event_t event, uint64_t spin_delay, std::chrono::microseconds min_timeout)
template<typename Stop_condition >
Wait_stats	wait (Stop_condition stop_condition)

Private Attributes
const log_t &	m_log
os_event_t	m_event
const uint32_t	m_spin_delay
const std::chrono::microseconds	m_min_timeout

Detailed Description

Small utility which is used inside log threads when they have to wait for next interesting event to happen.

For performance reasons, it might make sense to use spin-delay in front of the wait on event in such cases. The strategy is first to spin and then to fallback to the wait on event. However, for idle servers or work-loads which do not need redo being flushed as often, we prefer to avoid spinning. This utility solves such problems and provides waiting mechanism.

Constructor & Destructor Documentation

Log_thread_waiting()

Log_thread_waiting::Log_thread_waiting ( const log_t &  log, os_event_t  event, uint64_t  spin_delay, std::chrono::microseconds  min_timeout  )

inline

Member Function Documentation

wait()

template<typename Stop_condition >

Wait_stats Log_thread_waiting::wait ( Stop_condition  stop_condition )

inline

We might read older value, it just decides on spinning. Correctness does not depend on this. Only local performance might depend on this but it's anyway heuristic and depends on average which by definition has lag. No reason to make extra barriers here.

Member Data Documentation

m_event

os_event_t Log_thread_waiting::m_event

private

m_log

const log_t& Log_thread_waiting::m_log

private

m_min_timeout

const std::chrono::microseconds Log_thread_waiting::m_min_timeout

private

m_spin_delay

const uint32_t Log_thread_waiting::m_spin_delay

private

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The documentation for this struct was generated from the following file:

• storage/innobase/log/log0write.cc