pgsql: Increase the default value of effective_cache_size to 4GB.

Increase the default value of effective_cache_size to 4GB.

Per discussion, the old value of 128MB is ridiculously small on modern
machines; in fact, it's not even any larger than the default value of
shared_buffers, which it certainly should be. Increase to 4GB, which
is unlikely to be any worse than the old default for anyone, and should
be noticeably better for most. Eventually we might have an autotuning
scheme for this setting, but the recent attempt crashed and burned,
so for now just do this.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b910d7ea358b0134d170ebf4002248df25a5f244

Modified Files
--------------
doc/src/sgml/config.sgml | 4 ++--
doc/src/sgml/release-9.4.sgml | 18 +++++++++---------
src/backend/utils/misc/postgresql.conf.sample | 2 +-
src/include/optimizer/cost.h | 2 +-
4 files changed, 13 insertions(+), 13 deletions(-)