mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-05-14 19:07:15 +02:00
Code Issues Projects Releases Packages Wiki Activity

MDEV-24671 fixup: Merge lock_sys_t::wait_pending into wait_count

Browse source 
The maximum number of concurrently waiting transactions is one less
than the maximum number of concurrent transactions.

A 45-bit cumulative counter of lock waits will support more than
one million lock waits per second for a year.
This commit is contained in:
Marko Mäkelä 2021-03-09 08:58:28 +02:00
commit bda8a2a63a
2 changed files with 19 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

17
storage/innobase/include/lock0lock.h
View file

@ -670,10 +670,11 @@ public:
/** mutex covering lock waits; @see trx_lock_t::wait_lock */
MY_ALIGNED(CPU_LEVEL1_DCACHE_LINESIZE) mysql_mutex_t wait_mutex;
private:
/** Cumulative number of lock waits; protected by wait_mutex */
ulint wait_count;
/** Pending number of lock waits; protected by wait_mutex */
uint32_t wait_pending;
/** The increment of wait_count for a wait. Anything smaller is a
pending wait count. */
static constexpr uint64_t WAIT_COUNT_STEP= 1U << 19;
/** waits and total number of lock waits; protected by wait_mutex */
uint64_t wait_count;
/** Cumulative wait time; protected by wait_mutex */
uint32_t wait_time;
/** Longest wait time; protected by wait_mutex */
@ -818,9 +819,13 @@ public:
inline void wait_resume(THD *thd, my_hrtime_t start, my_hrtime_t now);
/** @return pending number of lock waits */
ulint get_wait_pending() const { return wait_pending; }
ulint get_wait_pending() const
{
return static_cast<ulint>(wait_count & (WAIT_COUNT_STEP - 1));
}
/** @return cumulative number of lock waits */
ulint get_wait_cumulative() const { return wait_count; }
ulint get_wait_cumulative() const
{ return static_cast<ulint>(wait_count / WAIT_COUNT_STEP); }
/** Cumulative wait time; protected by wait_mutex */
ulint get_wait_time_cumulative() const { return wait_time; }
/** Longest wait time; protected by wait_mutex */