pgsql: Separate block sampling functions

Separate block sampling functions

Refactoring ahead of tablesample patch

Requested and reviewed by Michael Paquier

Petr Jelinek

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/83e176ec18d2a91dbea1d0d1bd94c38dc47cd77c

Modified Files
--------------
contrib/file_fdw/file_fdw.c         |    9 +-
contrib/postgres_fdw/postgres_fdw.c |   10 +-
src/backend/commands/analyze.c      |  225 +---------------------------------
src/backend/utils/misc/Makefile     |    2 +-
src/backend/utils/misc/sampling.c   |  226 +++++++++++++++++++++++++++++++++++
src/include/commands/vacuum.h       |    3 -
src/include/utils/sampling.h        |   44 +++++++
7 files changed, 287 insertions(+), 232 deletions(-)