pgsql: Add new function BackgroundWorkerInitializeConnectionByOid.

Add new function BackgroundWorkerInitializeConnectionByOid.

Sometimes it's useful for a background worker to be able to initialize
its database connection by OID rather than by name, so provide a way
to do that.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/5d2f957f3f9dcd88384780876f535b423151f9bf

Modified Files
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doc/src/sgml/bgworker.sgml | 17 ++++++++++-------
src/backend/bootstrap/bootstrap.c | 2 +-
src/backend/postmaster/autovacuum.c | 4 ++--
src/backend/postmaster/postmaster.c | 25 ++++++++++++++++++++++++-
src/backend/tcop/postgres.c | 2 +-
src/backend/utils/init/miscinit.c | 8 +++++---
src/backend/utils/init/postinit.c | 13 ++++++++-----
src/include/miscadmin.h | 4 ++--
src/include/postmaster/bgworker.h | 3 +++
9 files changed, 56 insertions(+), 22 deletions(-)