pgsql: Split up wal-logging items: < * Allow control over which tables

Log Message:
-----------
Split up wal-logging items:

< * Allow control over which tables are WAL-logged [walcontrol]
> * Allow WAL logging to be turned off for a table, but the table
> might be dropped or truncated during crash recovery [walcontrol]
< commit. To do this, only a single writer can modify the table, and
< writes must happen only on new pages. Readers can continue accessing
< the table. This would affect COPY, and perhaps INSERT/UPDATE too.
< Another option is to avoid transaction logging entirely and truncate
< or drop the table on crash recovery. These should be implemented
< using ALTER TABLE, e.g. ALTER TABLE PERSISTENCE [ DROP | TRUNCATE |
< STABLE | DEFAULT ]. Tables using non-default logging should not use
< referential integrity with default-logging tables, and tables using
< stable logging probably can not have indexes. One complexity is
< the handling of indexes on TOAST tables.
> commit. This should be implemented using ALTER TABLE, e.g. ALTER
> TABLE PERSISTENCE [ DROP | TRUNCATE | DEFAULT ]. Tables using
> non-default logging should not use referential integrity with
> default-logging tables. A table without dirty buffers during a
> crash could perhaps avoid the drop/truncate.
>
> * Allow WAL logging to be turned off for a table, but the table would
> avoid being truncated/dropped [walcontrol]
>
> To do this, only a single writer can modify the table, and writes
> must happen only on new pages so the new pages can be removed during
> crash recovery. Readers can continue accessing the table. Such
> tables probably cannot have indexes. One complexity is the handling
> of indexes on TOAST tables.

Modified Files:
--------------
pgsql/doc:
TODO (r1.1757 -> r1.1758)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.1757&r2=1.1758)
pgsql/doc/src/FAQ:
TODO.html (r1.262 -> r1.263)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/FAQ/TODO.html.diff?r1=1.262&r2=1.263)