Re: Removal of temp tables

Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> Here is an updated patch that uses underscores in temp table names so
> the DROP doesn't have to quote the table name:

That seems like a reasonable idea, but don't do it to temp file
names, ie, drop this part of the diff:

> *** src/backend/storage/file/fd.c 2001/06/11 04:12:29 1.81
> --- src/backend/storage/file/fd.c 2001/06/14 16:34:02
> ***************
> *** 756,762 ****
> * transaction and database instance.
> */
> snprintf(tempfilepath, sizeof(tempfilepath),
> ! "%s/%s%d.%ld", PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
> MyProcPid, tempFileCounter++);

> /*
> --- 756,762 ----
> * transaction and database instance.
> */
> snprintf(tempfilepath, sizeof(tempfilepath),
> ! "%s/%s%d_%ld", PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
> MyProcPid, tempFileCounter++);

> /*

There's no reason to spell temp file names as if they were rel names,
and probably it's best not to make them look the same.

Also, an item I've ranted about before:

> + #define is_temp_relname(relname) \
> + (!strncmp(relname, PG_TEMP_REL_PREFIX, strlen(PG_TEMP_REL_PREFIX)))

It's bad style to treat the result of strcmp or strncmp as though it
were a boolean, cf
http://fts.postgresql.org/db/mw/msg.html?mid=68294
Write (strncmp(...) == 0) instead.

Otherwise the patch seems reasonable, although I wonder what your
motivation was for choosing these particular IsSystemRelationName calls
to tweak. It looks like you did more than the minimum needed to allow
a DROP TABLE; why these extra ones and not others? (Not that I'm
encouraging you to go around and hit every IsSystemRelationName call.
If you did, that'll just be more changes that I suspect we'll have to
remove again in the long run. I'm just curious why you touched, for
example, VACUUM.)

regards, tom lane