Make various variables const (read-only).

These changes should generally improve correctness/maintainability.
A nice side benefit is that several kilobytes move from initialized
data to text segment, allowing them to be shared across processes and
probably reducing copy-on-write overhead while forking a new backend.
Unfortunately this doesn't seem to help libpq in the same way (at least
not when it's compiled with -fpic on x86_64), but we can hope the linker
at least collects all nominally-const data together even if it's not
actually part of the text segment.

Also, make pg_encname_tbl[] static in encnames.c, since there seems
no very good reason for any other code to use it; per a suggestion
from Wim Lewis, who independently submitted a patch that was mostly
a subset of this one.

Oskari Saarenmaa, with some editorialization by me

1 files changed, 2 insertions, 1 deletions

diff --git a/src/include/common/relpath.h b/src/include/common/relpath.h
index 8795464a27a..23a226d058e 100644
--- a/src/include/common/relpath.h
+++ b/src/include/common/relpath.h
@@ -25,7 +25,8 @@
 #define TABLESPACE_VERSION_DIRECTORY	"PG_" PG_MAJORVERSION "_" \
 									CppAsString2(CATALOG_VERSION_NO)
 
-extern const char *forkNames[];
+extern const char *const forkNames[];
+
 extern int	forkname_chars(const char *str, ForkNumber *fork);
 extern char *relpathbackend(RelFileNode rnode, BackendId backend,
 			   ForkNumber forknum);