Re: [Patch] Make block and file size for WAL and relations defined at cluster creation

On Sun, Dec 31, 2017 at 12:00 PM, Remi Colinet <remi(dot)colinet(at)gmail(dot)com> wrote:
> Below patch makes block and file sizes defined at cluster creation for both
> the WAL and the relations. This avoids having different server builds for
> each possible combination of block size and file sizes.\

The email thread where we discussed making the WAL segment size
configurable at initdb time contained a detailed rationale, explaining
why it was useful to be able to make such a change. The very short
version is that, if a system is generating WAL at a very high rate,
being able to group that WAL into fewer, larger files makes life
easier since, for example, the latency requirements for
archive_command are not as tight, and "ls pg_wal" doesn't have to go
into the tank just trying to read the directory contents.

Your email doesn't seem to contain a rationale explaining why the
block and file sizes should be run-time configurable. There may be a
very good reason, but can you explain what it is?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company