Re: Bg_writer and checkpointer - Mailing list pgsql-admin

From Rajesh Kumar
Subject Re: Bg_writer and checkpointer
Date
Msg-id CAJk5AtYEmSw264V19my8n_mVzx7iytib3c5+H96=z5ktN2VaZA@mail.gmail.com
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In response to Bg_writer and checkpointer  (Rajesh Kumar <rajeshkumar.dba09@gmail.com>)
List pgsql-admin
Help me with clear information plz

On Fri, 19 Apr 2024, 20:46 Rajesh Kumar, <rajeshkumar.dba09@gmail.com> wrote:
I have read multiple online blogs, watched videos and still not clarified about 1. Actual difference between bg_writer and checkpointer. When I am querying update set, If bgwriter flushes dirty buffer to base every 200ms(bgwriter_delay), why would I need checkpointer to invoke bgwriter? 
Same way, what happens for insert query?

1. How the flow works?

Dml-->wal_buffer-->also copied to shared_buffer--> commit-->flushed to pg_wal using wal writer -->checkpointer-->fsync to datapath-->bgwriter flushed to base.


Correct me the flowchart 

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