Re: Quick-and-dirty compression for WAL backup blocks

Hello all,

I am interested in how to "Compress WAL entries".
Then, I study the source now, and read this discussion.

There are some questions.

1.
In the XLogInsert(), it makes two kinds of logs, "whole buffer(page)
log" and "partial buffer log", isn't it?  Is it only "who buffer log"
to generate a log with "hole"?

2.
Tom Lane wrote:
> The overhead needed is only 2 bytes to show the number of
> bytes removed.

In "whole buffer log", there is a page header that includes offset of
"hole" (lower and upper). If we use that information, we don't need
any overhead, do we?

# Sorry for my bad english..

-- 
Junji Teramoto