Re: Theory question
| От | Raghavendra |
|---|---|
| Тема | Re: Theory question |
| Дата | |
| Msg-id | CA+h6Ahhdgo1pQr1A+J21gBDHdpJk9h_OoVdaGxOOR_96saH=Pw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Theory question (Jayadevan M <maymala.jayadevan@gmail.com>) |
| Список | pgsql-general |
JayadevanRegards,Hi,What are the real differences between the bgwriter and checkpointer process? Both of them write data from the buffer to the data files, right? Is it just a matter of 'when' they write?
by others
on
my understanding described below.
AFAIK, they share the load of writing dirty-buffers to disk, though they are defined to serve different purpose. Basically, background writer process sole function is to write "dirty" shared buffers to disk and evict those pages from shared buffer pool. Whereas checkpoint, arrives to write all dirty data pages in shared_buffers to disk only when checkpoint_timeout or when all checkpoint_segments are filled, whichever comes first. However, BG Writer (Writer Process) will be continuously
trickle out dirty pages to disk so that by the time checkpoint arrives there will be left only with f
ew dirty pages, instead of having
lots of dirty pages
to carry out by i
tself alone
and cause I/O loaded
.---
Regards,
Raghavendra
В списке pgsql-general по дате отправления: