Replace BackendIds with 0-based ProcNumbers

Now that BackendId was just another index into the proc array, it was
redundant with the 0-based proc numbers used in other places. Replace
all usage of backend IDs with proc numbers.

The only place where the term "backend id" remains is in a few pgstat
functions that expose backend IDs at the SQL level. Those IDs are now
in fact 0-based ProcNumbers too, but the documentation still calls
them "backend ids". That term still seems appropriate to describe what
the numbers are, so I let it be.

One user-visible effect is that pg_temp_0 is now a valid temp schema
name, for backend with ProcNumber 0.

Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/[email protected]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index 2b57addbdb9..fc5f883ce14 100644
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -74,7 +74,7 @@ typedef SMgrRelationData *SMgrRelation;
 	RelFileLocatorBackendIsTemp((smgr)->smgr_rlocator)
 
 extern void smgrinit(void);
-extern SMgrRelation smgropen(RelFileLocator rlocator, BackendId backend);
+extern SMgrRelation smgropen(RelFileLocator rlocator, ProcNumber backend);
 extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
 extern void smgrpin(SMgrRelation reln);
 extern void smgrunpin(SMgrRelation reln);