[pgpool-committers: 7606] pgpool: Doc: enhance show pool_cache manual.

[Tatsuo Ishii]

Doc: enhance show pool_cache manual.

Add note that not all columns shows meaningful values when cache
storage is memcached.

Branch
------
V4_2_STABLE

Details
-------
https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=b3bddbe91c329cea0ffa3159e1b5f799a476ccb8

Modified Files
--------------
doc.ja/src/sgml/ref/show_pool_cache.sgml | 12 ++++++++++++
doc/src/sgml/ref/show_pool_cache.sgml    |  8 ++++++++
2 files changed, 20 insertions(+)