Re: TRUNCATE on foreign table

On Sun, Apr 11, 2021 at 03:45:36PM +0530, Bharath Rupireddy wrote:
> On Sun, Apr 11, 2021 at 9:47 AM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
> > Also, you currently test:
> > > + if (extra & TRUNCATE_REL_CONTEXT_ONLY)
> >
> > but TRUNCATE_REL_ aren't indepedent bits, so shouldn't be tested with "&".
>
> Yeah this is an issue. We could just change the #defines to values
> 0x0001, 0x0002, 0x0004, 0x0008 ... 0x0020 and so on and then testing
> with & would work. So, this way, more than option can be multiplexed
> into the same int value. To multiplex, we need to think: will there be
> a scenario where a single rel in the truncate can have multiple
> options at a time and do we want to distinguish these options while
> deparsing?
>
> #define TRUNCATE_REL_CONTEXT_NORMAL 0x0001 /* specified without
> ONLY clause */
> #define TRUNCATE_REL_CONTEXT_ONLY 0x0002 /* specified with
> ONLY clause */
> #define TRUNCATE_REL_CONTEXT_CASCADING 0x0004 /* not specified
> but truncated
>
> And I'm not sure what's the agreement on retaining or removing #define
> values, currently I see only TRUNCATE_REL_CONTEXT_ONLY is being used,
> others are just being set but not used. As I said upthread, it will be
> good to remove the unused macros/enums, retain only the ones that are
> used, especially TRUNCATE_REL_CONTEXT_CASCADING this is not required I
> feel, because we can add the child partitions that are foreign tables
> to relids as just normal foreign tables with TRUNCATE_REL_CONTEXT_ONLY
> option.

Converting to "bits" would collapse TRUNCATE_REL_CONTEXT_ONLY and
TRUNCATE_REL_CONTEXT_NORMAL into a single bit. TRUNCATE_REL_CONTEXT_CASCADING
could optionally be removed.

+1 to convert to bits instead of changing "&" to "==".

--
Justin