Please explain difference between these processes in short words. Official documentation didn't give me any grasp =(
All of them for flushing dirty pages from shared buffers to disk (wal or db disk?), but what is actual difference?
How is the writing process from wal to db disk going?
The WAL writer does not flush dirty pages from cache, it writes WAL.
The checkpointer flushes all dirty pages at certain intervals to create a point for recovery to start.
The background writer flushes some dirty pages between checkpoints so that there are always enough clean pages to go around.