Возможно, стоит пояснить разницу между синхронизацией из thread/process-safe и синхронизацией с помощью Lock🤔
Наша задача — заставить разные процессы и потоки обращаться к базе данных (или любым другим ресурсам) последовательно. Чтобы не случилось так называемого race condition, то есть состояние гонки. Это когда разные потоки или процессы пытаются одновременно что-то сделать с одним и тем же ресурсом.
В этом случае нам нужна какая-то логика ограничения. Пока один процесс не завершил своё действие, другие не могут получить доступ к ресурсу.
Так вот, thread-safe и process-safe означает что отдельно взятые операции записи в БД гарантированно будут последовательны. Запросы из разных процессов или потоков выстроятся в очередь и не будут мешать друг другу. Лучше всего когда этот блок реализован на уровне БД в виде атомарных операций или ещё как-то.
Но зачем нам тогда еще дополнительный Lock?
Этот способ синхронизации используется когда процесс никак не укладывается в одно действие и должен сделать множество операций прежде чем дать доступ следующему. В этом случае процесс ставит некий глобальный Lock на ресурс и никто другой, даже получив законное право на доступ, не может ничего сделать. Все ждут пока этот Lock не будет снят.
Это решается на уровне приложения и правильность реализации полностью в вашей ответственности. Например, если забыли разблокировать или сделали перекрёстный Lock (Deadlock как на картинке), то всё зависнет в бесконечном ожидании.
#basic
*FRACTION OF SECONDS*
Woke up. I knew I was late. Coz that was my routine. And coz of a simple logic, why be excited to wake up early and go to a place you hate and do something that you hate!
I sighed when my mouth tasted coffee before colgate...Ahh! how I love normal days, It was a normal day. At least that's what I thought. Papa was there looking up from the newspaper at me with a sense of pity.
I sort of ignored that and walked out through the front door, but the next sight, a brand new beautiful ladybird and an even more beautiful rider, with short black hair waving in the wind, in a skirt that knew well not to cover her beautiful legs... Well I couldn't ignore that! Just a fraction of seconds and I had already captured her. Made her mine. Is this what they call...
Oops!! She looked at me. Damn it! She caught me staring at her! I looked away whistling. I looked again, did I see a smile?
I heard Mom shouting my name out aloud. I knew I had to rush. As I was rushing inside I heard a loud thud. I turned back and saw the beautiful ladybird lying on the road. It was only a fraction of second, yet my mind talked to me in infinite speed...Somethings...what did he say I don't remember anymore. I remember rushing back to the house.
One year I didn't talk to our new neighbour who was an year older than me.Days went by. Mom had started packing things up one evening I came back from school. Papa received his transfer letter.
Now whenever I see a cycle I think. What would've happened? Why hadn't I stopped my mind talking to me? Why hadn't I I rushed 'out'side than 'in'side? All in a fraction of second!
#JOHN PAUL BENOY
#Review
*FRACTION OF SECONDS*
Woke up. I knew I was late. Coz that was my routine. And coz of a simple logic, why be excited to wake up early and go to a place you hate and do something that you hate!
I sighed when my mouth tasted coffee before colgate...Ahh! how I love normal days, It was a normal day. At least that's what I thought. Papa was there looking up from the newspaper at me with a sense of pity.
I sort of ignored that and walked out through the front door, but the next sight, a brand new beautiful ladybird and an even more beautiful rider, with short black hair waving in the wind, in a skirt that knew well not to cover her beautiful legs... Well I couldn't ignore that! Just a fraction of seconds and I had already captured her. Made her mine. Is this what they call...
Oops!! She looked at me. Damn it! She caught me staring at her! I looked away whistling. I looked again, did I see a smile?
I heard Mom shouting my name out aloud. I knew I had to rush. As I was rushing inside I heard a loud thud. I turned back and saw the beautiful ladybird lying on the road. It was only a fraction of second, yet my mind talked to me in infinite speed...Somethings...what did he say I don't remember anymore. I remember rushing back to the house.
One year I didn't talk to our new neighbour who was an year older than me.Days went by. Mom had started packing things up one evening I came back from school. Papa received his transfer letter.
Now whenever I see a cycle I think. What would've happened? Why hadn't I stopped my mind talking to me? Why hadn't I I rushed 'out'side than 'in'side? All in a fraction of second!
#JOHN PAUL BENOY
#Review
#short story
Former US National Security Advisor John Bolton:
“Although you could potentially remove the ayatollah, that would leave the IRGC in place, and the government in Iran is the IRGC, while the ayatollahs act as a religious cover or an ideological cover for them.
I think Trump is just hoping that this show of American power will intimidate the ayatollahs. If I were still his adviser, I would be happy to tell him that it won’t work.
They won’t be intimidated. But Trump really thinks minute by minute; he doesn’t think strategically.”
#john#bolton#trump#ayatollah
📱American Оbserver - Stay up to date on all important events
🇺🇸
L-l恋l爱a刺c客k- 恋爱刺客 John Tucker Must Die (2006)
直达链接：https://pan.quark.cn/s/4ea1760bcdae
#恋爱刺客#John Tucker Must Die #约翰·塔克必死
链接：https://link3.cc/sf_com
#电影#喜剧#美国#00年代