Re: Allow CLUSTER, VACUUM FULL and REINDEX to change tablespace on the fly

On 2020-Dec-23, Michael Paquier wrote:

> bool
> -reindex_relation(Oid relid, int flags, int options)
> +reindex_relation(Oid relid, int flags, ReindexOptions *options)
> {
> Relation rel;
> Oid toast_relid;

Wait a minute. reindex_relation has 'flags' and *also* 'options' with
an embedded 'flags' member? Surely that's not right. I see that they
carry orthogonal sets of options ... but why aren't they a single
bitmask instead of two separate ones? This looks weird and confusing.

Also: it seems a bit weird to me to put the flags inside the options
struct. I would keep them separate -- so initially the options struct
would only have the tablespace OID, on API cleanliness grounds:

struct ReindexOptions
{
tablepaceOid oid;
};
extern bool
reindex_relation(Oid relid, bits32 flags, ReindexOptions *options);

I guess you could argue that it's more performance to set up only two
arguments to the function call instead of three .. but I doubt that's
measurable for anything in DDL-land.

But also, are we really envisioning that these routines would have all
that many additional options? Maybe it is sufficient to do just

extern bool
reindex_relation(Oid relid, bits32 flags, tablespaceOid Oid);