On 2020-11-17 12:53, lchch1...@sina.cn wrote:
Thanks for your comments.
You're understanding is almost the same as mine.
It describes when not only backends but also other backgrounds
initialize a new wal page,
wal buffer's space is already used and there is no space.
'Total number of times WAL data written to the disk because a
backend
yelled a wal buffer for an advanced wal page'
Thanks for your suggestion.
I wondered that users may confuse about how to use
"wal_buffers_full" and how to tune parameters.
I thought the reason which wal buffer has no space is
important for users to tune the wal_buffers parameter.
How about the following comments?
'Total number of times WAL data was written to the disk because WAL
buffers got full
when to initialize a new WAL page'
Or what about the following?
Total number of times WAL data was written to the disk, to claim the
buffer page to insert new
WAL data when the WAL buffers got filled up with unwritten WAL data.
As my understand we can not say 'full' because every wal page mapped a
special wal buffer slot.
When a wal page need to be write, but the buffer slot was occupied by
other wal page. It need to
wait the wal buffer slot released. So i think we should say it
'occupied' not 'full'.
Maybe:
Total number of times WAL data was written to the disk, to claim the
buffer page to insert new
WAL data when the special WAL buffer occupied by other page.
OK, I will change the above sentence since there are some sentences
like "space occupied by", "disk blocks occupied", and so on in the
documents.
Do we need to change the column name from "wal_buffers_full"
to another name like "wal_buffers_all_occupied"?
Regards
--
Masahiro Ikeda
NTT DATA CORPORATION
