pgsql: Simplify determining logical replication worker types.

Simplify determining logical replication worker types.

We deduce a LogicalRepWorker's type from the values of several different
fields ('relid' and 'leader_pid') whenever logic needs to know it.

In fact, the logical replication worker type is already known at the time
of launching the LogicalRepWorker and it never changes for the lifetime of
that process. Instead of deducing the type, it is simpler to just store it
one time, and access it directly thereafter.

Author: Peter Smith
Reviewed-by: Amit Kapila, Bharath Rupireddy
Discussion: http://postgr.es/m/CAHut+PttPSuP0yoZ=9zLDXKqTJ=d0bhxwKaEaNcaym1XqcvDEg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2a8b40e3681921943a2989fd4ec6cdbf8766566c

Modified Files
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.../replication/logical/applyparallelworker.c | 3 ++-
src/backend/replication/logical/launcher.c | 31 +++++++++++++++-------
src/backend/replication/logical/tablesync.c | 3 ++-
src/include/replication/worker_internal.h | 22 +++++++++++----
src/tools/pgindent/typedefs.list | 1 +
5 files changed, 43 insertions(+), 17 deletions(-)