Use conditional variable to wait for next MultiXact offset In one multixact.c edge case, we need a mechanism to wait for one multixact offset to be written before being allowed to read the next one. We used to handle this case by sleeping for one millisecond and retrying, but such sleeps have been reported as problematic in production cases. We can avoid the problem by using a condition variable: readers sleep on it and then every creator of multixacts broadcasts into the CV when creation is sufficiently far along.
Author: Kyotaro Horiguchi <horikyotaj...@gmail.com> Reviewed-by: Andrey Borodin <amboro...@acm.org> Discussion: https://postgr.es/m/47a598f4-b4e7-4029-8fec-a06a6c3cb...@yandex-team.ru Discussion: https://postgr.es/m/20200515.090333.24867479329066911.horikyota.ntt Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/a0e0fb1ba56ff4323542c75ce997a41d31ad28a0 Modified Files -------------- src/backend/access/transam/multixact.c | 30 +++++++++++++++++++++++-- src/backend/utils/activity/wait_event_names.txt | 1 + 2 files changed, 29 insertions(+), 2 deletions(-)
