Hi all, I have a high traffic database, where I'm interested in changing the wal segment size to a larger value. I haven't found much documentation about how to change the segment size of an existing database. The obvious, safe solution would be to create a new database cluster and dump/reload. This isn't ideal for a large database though. Pg_resetwal has a wal-segsize option, but the documentation doesn't provide much guidance beyond that it's there. The pg_resetwal manpage also has big warnings all over it about how the tool can corrupt your database cluster. So my question is, is it safe to change wal-segsize using pg_resetwal following a clean shutdown of the database? Just reading the docs, it seems like the corruption issues are more around non-graceful shutdowns or crash scenarios, with incomplete transactions being wiped out by a wal reset. If the database was shutdown cleanly this doesn't *seem* like it would be an issue. Has anyone had experience doing this? I assume this would break any physical replication standbys. Any other gotchas I should be looking out for? I've tested on a trivial (empty) database cluster, and everything seems okay. But corruption might be difficult to detect until it's too late. Thanks, James Lucas
