pgsql: Add TIMING option to EXPLAIN, to allow eliminating of timing ove

Add TIMING option to EXPLAIN, to allow eliminating of timing overhead.

Sometimes it may be useful to get actual row counts out of EXPLAIN
(ANALYZE) without paying the cost of timing every node entry/exit.
With this patch, you can say EXPLAIN (ANALYZE, TIMING OFF) to get that.

Tomas Vondra, reviewed by Eric Theise, with minor doc changes by me.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/af7914c6627bcf0b0ca614e9ce95d3f8056602bf

Modified Files
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contrib/auto_explain/auto_explain.c | 19 ++++++++++++++-
doc/src/sgml/ref/explain.sgml | 16 ++++++++++++
src/backend/commands/explain.c | 45 +++++++++++++++++++++++++++++-----
src/backend/executor/instrument.c | 34 ++++++++++++++++----------
src/include/commands/explain.h | 1 +
src/include/executor/instrument.h | 4 ++-
6 files changed, 97 insertions(+), 22 deletions(-)