Обсуждение: pgsql: In documentaiton, clarify which commands have reduced WAL volume

In documentaiton, clarify which commands have reduced WAL volume for
wal_level = minimum.

Backpatch to 9.1 and 9.0.

Branch
------
REL9_0_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/072e6076d10955da5ee46416607a8ff19afd6b40

Modified Files
--------------
doc/src/sgml/config.sgml |   17 ++++++++++++-----
1 files changed, 12 insertions(+), 5 deletions(-)