pgsql: Make EXPLAIN (BUFFERS) track blocks dirtied, as well as those wr

Make EXPLAIN (BUFFERS) track blocks dirtied, as well as those written.

Also expose the new counters through pg_stat_statements.

Patch by me. Review by Fujii Masao and Greg Smith.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/2254367435fcc4a31cc3b6d8324e33c5c30f265a

Modified Files
--------------
contrib/pg_stat_statements/Makefile | 3 +-
.../pg_stat_statements--1.0--1.1.sql | 40 +++++++++++++++++++
.../pg_stat_statements/pg_stat_statements--1.1.sql | 41 ++++++++++++++++++++
contrib/pg_stat_statements/pg_stat_statements.c | 21 +++++++++-
.../pg_stat_statements/pg_stat_statements.control | 2 +-
doc/src/sgml/pgstatstatements.sgml | 14 +++++++
doc/src/sgml/ref/explain.sgml | 12 ++++-
src/backend/commands/explain.c | 16 ++++++-
src/backend/executor/instrument.c | 2 +
src/backend/storage/buffer/bufmgr.c | 1 +
src/backend/storage/buffer/localbuf.c | 4 ++
src/include/executor/instrument.h | 2 +
12 files changed, 148 insertions(+), 10 deletions(-)