Re: [HACKERS] [PATCH] Rename pg_switch_xlog to pg_switch_wal

We decided s/pg_xlog/pg_wal/ was necessary because people lost their
data, and we couldn't come up with a reasonable way to change it without
the name. The tradeoff is dataloss vs. dealing with directory renaming
in a few lowlevel tools.  So we decided to change the name.  It seems
breakage was unavoidable.

For me the renaming of functions, binaries, etc, is different because
the benefit is long-term avoidance of a bit of confusion, with the
shorter term price being tool breakages and confusion because
documentation/guides/... for different versions don't apply anymore, and
the search terms don't help anymore.  But we're still changing this,
even though breakage seems avoidable.

And that fits into the bigger topic of us doing minor cleanups without a
lot of concern for backward compatibility, e.g. like us whacking things
around in pg_stat_activity for most of the last releases - nearly all of
those could have been done in a compatible manner, without even smelling
that badly.

I hear these complaints about postgres most frequently: 1) replication
sucks. 2) way too slow on analytics queries. 3) existing admin tools
suck. 4) self written admin tools (required due to 3)) constantly break.

There's a lot being done on 1) and 2). There's very little in-core
progress about 3). We're getting worse on 4).