Re: Theory question

On Tue, Nov 12, 2013 at 6:57 AM, Jayadevan M <maymala(dot)jayadevan(at)gmail(dot)com>wrote:

> 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?
>

I believe, "Checkpoint" is one of the responsible duty of bgwriter process.
AFAIK from PG 9.2 onwards, we have another independent process called
"CKPTR process" which independently works. "Bgwriter" simply move the
shared_buffer's pages into local disk on the basis of LRU method. Where as
"CKPTR process" moves all the dirty buffers into local disk, and make a
transaction log sequence, at which all the data files have been updated to
reflect this information.

Best Regards,
Dinesh
manojadinesh.blogspot.com