postgresql.conf and postgres options

I've just been looking through the options which can and cannot be set in
postgresql.conf and have a few points to raise.

1. There are some undocumented options which appear to relate to WAL:

Name Variable Default Set by

checkpoint_timeout CheckPointTimeout 300 Startup
wal_buffers XLOGbuffers 8 Startup
wal_files XLOGfiles 0 Startup
wal_debug &XLOG_DEBU 0 Superuser
commit_delay &CommitDelay 5 User

Is there any text anywhere to explain what these do? (Point me to that or
some commented code, and I'll write a documentation patch.)

2. The following command line options to postgres don't have an equivalent in
postgresql.conf. Is that intentional? (I suppose it is in several cases,
and I have left out some where it is obviously intentional.) I can't see
why these items can't be put in the configuration file:

Option Action

-C Noversion = true [not documented in postgres man page]
-D potential_Datadir = arg [set PGDATA]
-E EchoQuery = true [echo queries to log]
-e EuroDates = true [use European format for dates]
-N UseNewLine = 0 [newline is not a query separator]
-o [set stdout, stderr to file arg]

3. I see the -E is documented as being for stand-alone mode only; in fact it
is useful for getting the query into the backend log in normal operation.

4. The documentation for -o is confusing:

-o file-name

Sends all debugging and error output to OutputFile. If the backend
is running under the postmaster, error messages are still sent to
the frontend process as well as to OutputFile, but debugging output
is sent to the controlling tty of the postmaster (since only one
file descriptor can be sent to an actual file).

I think this is saying that, under the postmaster, debugging output does
not get sent to OutputFile, and error messages are sent both to OutputFile
and to the frontend. Is that correct?

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
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